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cMP - the open source high-end Memory Player

41.183.0.21

Posted on December 30, 2007 at 05:42:01
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
cMP

The open source high-end Memory Player

December 2007

Music delivery is perfected. cMP (cics Memory Player) delivers memory playback (without RAMDisk or other utilities) thereby eliminating disk interference during playback.

In creating cMP, its critical objective was the implementation of fundamental designs that:

  1. Remove disk traffic interference during playback without having the inconvenience of manually loading files into a virtual RAM drive, etc..
  2. Ensure time critical sample delivery to the external DAC. Streaming of samples from precision upsampled (to 24/96) sound buffers to the soundcard must be fast, lean and mean! There's no room for any bottlenecks or overheads here, otherwise we risk increasing jitter and compromise Bit Transparency.
  3. Provide better power supply and remove the need for a ferrite core on the mouse connection.
  4. Provide flexibility to choose any player (Foobar2000, Winamp etc.).
  5. Further minimize the Windows footprint to that more optimal than XP's Embedded SP2 operating system as used in large scale commercial applications. This provides the foundation for the 2nd design goal.
  6. Offer a CD/DVD-ROM drive without impacting sound quality.
  7. Offer proper remote usability as locating that mouse cursor from a distance is cumbersome.
  8. Contain costs but also allow for a complete elegant one box solution.

Such designs in theory should render a stunning sonic experience. Its implementation however was a massive challenge. Did this theory meet the sonic expectations? Yes as evidenced in cMP's bit perfect performance and ultra low jitter.

How does it sound? The most descriptive word that comes to mind is emotional. cMP's sonic purity is truly profound. It grips those musical lines across any genre with remarkable precision. Soundstage improves, there's better layering and even more ambient information. Bass is tighter, with natural vocals & instruments.

FRONT



BACK



More pictures and screenshots are available from the cMP documentation link provided below.

FEEDBACK

Pre-release testing by music lovers located all over the world yielded further insight and perfection of cMP.

  • A music lover based in the US with limited or no computer training:

    This has been a great way to learn about computers in addition to making something very useful for enjoying music.

    Compared to my ###### (read expensive high-end traditional CD transport), even with some tweaking and learning left to do, this sounds much better. Dynamic, yet relaxed (effortless?).

    I started listening last night at 7:00 and had to force myself to go to bed at twelve. Amazing spaciousness. It is truly getting close to GREAT analog and is much better than average analog already. It is simply amazing.

    I found your instructions easy to follow ONCE I understood what I was being told to do. To repeat, I have never done anything like this before, so your instructions were clear without resorting to "hand holding". I think the process was easier than you warned. I kept saying to myself, "that wasn't so bad!"

    After cMP:

    My only audio friends are very analogue-centric. Sometime in January I am going to have them over to audition the cMP. I think they are going to be amazed. Of course, I am confident that JULI@ is going to be the icing on the cake. If this takes the whole thing another step closer I think they will be grateful that one can enjoy listening to CD's as much as LP's. Of course, in many ways your approach does things even LP's cannot do. It is becoming a toss-up, but the best kind; one can enjoy either one equally well!

  • A music lover based in Europe with more than 2000 CDs:

    the quality of sound reproduction is quite amazing. My motivation for building was that I am not wealthy and could never dream of, let alone buy, a high-end CD player. Even this project was considerably more than I could properly afford and I began it with some trepidation. But it's been well worth it.

    After cMP:

    I spent several hours last night testing the latest cMP. I did several A/B runs with cMP on the one hand and Foobar launched via old batch files and reading direct from disk on the other. There is no doubt in my mind that the sound using cMP is a significant improvement even with my modest setup.

    The quality is quite stunning, significantly better than previous. (My partner agrees with this - she's no audio junkie but she is an informed music lover.)

  • A music lover based in Australia:

    I have been wanting to relay to you my own experience with your methods and give you some feedback . So far, I have found your approach produces very good results so I must convey to you my thanks and appreciation. At some point soon I will formalise my thoughts and send them to you or post them. I believe what you have done has become an excellent resource/asset to people interested in PC Audio.


FEATURES

  1. Disk traffic interference during playback is eliminated. Advanced RAM playback is based on available physical RAM (as reported by Task Manager or Process Explorer). This means up to 4GB (XP's limit) can be used allowing for 24/192 RAM playback. Recommendation is to use 1GB RAM (which yields available physical RAM of ~830MB - enough for any CD at 16/44.1). cMP achieves memory playback via the system cache and not through a simulated virtual drive. This approach removes Windows disk I/O overheads (irrespective of whether disk is physical or virtual) hence, it's more optimal.

  2. Extensive Windows & Player (Foobar2000 or other) optimizations yielding much lower jitter and bit perfect delivery. System level optimizations are done at runtime (which cannot be achieved using .bat files and utilities like Process Explorer). cMP is designed to work with 32 CPU cores!

  3. Open architecture. cMP allows for any player to be used: Foobar2000, XXHighEnd, Winamp etc. (player just needs to handle .cue files like foobar2000 otherwise play entire .wav). Any ripper software can be used (as long as it conforms to .cue single file standard like those created by EAC). Additional flexibility is provided, for example use cMP to drive your HTPC playing any movie from any genre (a .cue file for each .iso file is needed).

  4. All .cue files are processed by cMP which means the player focuses only on playing the CD. In Foobar2000, the album list control component is not needed. In techno speak this is called separation of concerns.

  5. Power delivery to the mobo is improved by further reducing interference. The need for a ferrite core is removed.

  6. Full function remote control using a wireless mouse is achieved. Your entire library can be navigated: play any CD, eject it, jump to any track or change volume. This is achieved using just ONE mouse button: the Wheel! Use the mouse as a normal one (left-click) or hold it in your hand (like a remote control) and wheel away using your thumb. Of course other buttons are used for more convenience. There's no need to find that tiny mouse cursor and left click! (You can still do this if needed).

  7. Your entire library that you so diligently ripped is fully compatible with cMP. No proprietary / lock-in stuff here which forces you to re-rip. Just point cMP to your music folders containing .cue and .wav files (or flac or other). cMP supports any content file as long as cue files are defined for them. For flac content files, the known EAC bug of adding an additional .flac suffix to the content file's name must be removed (otherwise your cue's content file directive will not be found).

  8. CD/DVD-ROM drive is implemented without compromising playback quality. For the purist, this can be unplugged without opening computer or rebooting.

Bottom line: cMP is a (one box) highly advanced memory player that's easy to setup and use. cMP's core strength lies in newly developed operating system software components (built in c/c++) that uses XP SP 2 as a foundation. Windows Explorer is done away with while cMP takes over and more. Bit perfect delivery is achieved yielding an ultra high resolution of more than 23.5 bits (a limitation in measuring instruments prevents measuring cMP's perfect resolution). DAC's have yet to achieve this resolution (as a minimum of 141db SNR is needed)! For cMP's bit perfect measurements, see (Bit Perfect Measurement & Analysis ).


GETTING STARTED

Visit cicsMemoryPlayer.com where you'll find detailed easy to follow instructions and much more.

Ensuring clean AC power delivery to equipment is very important. For DAC, pre-amp and amplifiers, use a dedicated AC circuit. For source equipment, use another AC circuit as this is where cMP's main PSU should be powered from. Use another less important AC circuit for powering cMP's 2nd dirty power inlet. Use of quality power cords and line conditioners is recommended.


Special thanks to those that provided such brilliant feedback and suggestions during pre-release testing. cMP's software is at version 1.0b as more feedback is desired. Your input, insights, criticisms, experiences and suggestions all help.

Thank you.

 

Hide full thread outline!
    ...
RE: Need you to test current draw when display monitor is off. Also 2 more devices to disable!, posted on June 8, 2010 at 09:18:57
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
OK. Will do. By the way, I have identified suitable locations to terminate the power source to the chips. Simple soldering will be required but only one SMD device will need to be desoldered per chip in order to shut down the power. I will post more details soon.

 

RE: Stunning performance with Peaktech ( velleman ) Linear PSU powering p24 & p4, posted on June 9, 2010 at 11:15:16
etiennelemay


 
Hi,
I've read and reread your post (and follow ups) and I'm thinking of buying the Vellman (Peaktech) linear PS unit to provide power to my P4 connector (at least).
I have few questions though.

1 - Are you using 1 Vellman PS to power both P4 and P24 connector?

2 - The Vellman is connected directly to the P4 and connected to a PicoPSU for the P24?

Am I correct? I'm a bit confused about the P4/P24 and picoPSU setup.

Thanks

Etienne

 

RE: cMP - the open source high-end Memory Player, posted on June 10, 2010 at 21:08:38
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Hi Mihaylov

I understand that you or your friend are using the Zalman HD 160XT Plus. How
do you power up the LCD screen using separate linear power supply?

Currently I am still using the cable supplied by Zalman which is the 4 cables (red, yellow, purple, & black) connected to the P24 connector.

Do we need the 5VSB cable for the screen?


TIA

 

FOR JULI@ users: Removing output pulse trans could reveal more transparent sound!, posted on June 11, 2010 at 07:34:34
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
recently i was trying to do digital tube buffer for juli@, but it was failed. The digital pulse trans brand named HANRUN was removed, but the sound was better that the digital signal without going through.

 

Is there anyone has JULI@ circuit for digital?, posted on June 11, 2010 at 07:40:32
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
Is there anyone has JULI@ circuit for digital? I was think of doing digital tube buffer for digital SPDIF like what Lampizator does.. i tried it was failed by stealing the signal without the pulse trans.

 

RE: Not sure cMP works for me, what do u suggest?, posted on June 11, 2010 at 08:46:23
Dawnrazor
Audiophile

Posts: 12586
Location: N. California
Joined: April 9, 2004
TU,

As has been mentioned, you can convert to .wav or flac, and for creating cue sheets, use alan Jordans recursive cue sheet creator to do it quickly and painlessly.

You can also use his cplaylist creator that basically makes a cue sheet of your music that functions like a playlist...you can drag and drop songs to set it up.

In the link below under "Unrelated Items" on the bottom left

Cut to razor sounding violins

 

RE: cMP - the open source high-end Memory Player, posted on June 11, 2010 at 11:34:03
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010
"Do we need the 5VSB cable for the screen?" - Yes.
"How do you power up the LCD screen using separate linear power supply?" - LCD screen supplied by fourth module of the linear PSU through four wires: red and purple are connected to +5 V fourth module's output, yellow - to +12 V, black - to the ground.
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

RE: FOR JULI@ users: Removing output pulse trans could reveal more transparent sound!, posted on June 11, 2010 at 13:00:15
GStew
Audiophile

Posts: 633
Location: NE Mississippi
Joined: September 21, 2001
Just to clarify... did you physically remove the transformer or just remove it from the circuit by connecting at the input instead of the output...

TIA!

Greg in Mississippi
Everything matters!

 

RE: FOR JULI@ users: Removing output pulse trans could reveal more transparent sound!, posted on June 11, 2010 at 13:39:25
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
Yes, i did remove the entire pulse trans physically. It really sounds more transparent.
I hope someone could assist in tube buffering the SPDIF signal!

 

RE: cMP - the open source high-end Memory Player, posted on June 11, 2010 at 16:57:56
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Hi Mihaylov

Thanks for the clear and prompt reply.

 

Help please. "ERROR:Unable to get Access priviledges", posted on June 12, 2010 at 04:09:22
satosong
Audiophile

Posts: 3
Joined: June 7, 2010
,cMP says, when it starts. So, cMP can not play music.
My System: Win7 HomeP.32bits.
Current setting: EAC -> Recursive cue creator(Use two parents folders' in cue sheet name) -> cMP.
Someone, help please! --I'm a biginner on PC and English!
satosong

 

Run cMP as administrator.(nt), posted on June 12, 2010 at 05:44:24
riboge
Audiophile

Posts: 675
Joined: June 25, 2008
.

 

RE: Run cMP as administrator.(nt), posted on June 12, 2010 at 07:44:27
satosong
Audiophile

Posts: 3
Joined: June 7, 2010
Thank you,Mr.riboge. I have been logging in as administrator. What's wrong?
P.S. cMP Diagnotics is
"Proccess:explore.exe Terminated.
ERROR:Unable to get Access Priviledges.
optimise Proccesses:Cannot Set Access Priviledges. Play CD failed."
satosong

 

RE: Run cMP as administrator.(nt), posted on June 12, 2010 at 09:41:11
Try this: Go to Program files\cics Memory player and right-click on cicsMemoryPlayer.exe, Click "Properties", Click "Compatibility" tab. At the bottom, under the title "Privilege Level" tick "Run this program as an administrator". Apply. OK. Now see if cMP works.

I have permanently avoided these problems in Win7 by always setting up the real Administrator account right after installing Windows 7. It's easy with Win7 Pro and above, using secpol.msc, but with Windows 7 Home you should be able to enable the Administrator account by opening command prompt (WindowsKey+R > cmd), and typing: net user administrator /active:yes Then press Enter. Close the command window. Log off and you should now have the option to log on to the Administrator account. Set up your system, with cMP, on this account and no more privileges problems!

 

gdrv off but no change in current consumption, 1394....., posted on June 13, 2010 at 07:37:55
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Set gdrv off in device manager but there was no change in current consumption. 1394 was not present. Tried enabled in BIOS caused BSOD....

I made a mistake in my previous current measurement, there was acutally no current reduction on the 5V line. I was trying to do two tests at the same time - I put a battery as buffer in the wrong position causing erronous reading.


The following pix help understand the actual current consumption from the ATX P24.


GA H55M-UD2H defalut BIOS (9x133) (device on, no chip was removed)




-
-
-
-
-
GA H55M-UD2H BIOS optimised (9x100)in CMP




-
-
-
-
GA H55M-UD2H BIOS optimised CMP@96K




-
-
-
-
-
GA H55M-(D)2H BIOS optimised CMP@96K (2 video, 1 sound, 1 network, 1 IDE chip, 2 regulators were removed)




Now it is clear that removal of the chips will reduce 12V and 3.3V current consumption.

Further measurement confirmed that the 2 DVI-HDMI convertors are actually driven by the 3.3V directly from the ATX P24(I thought it would be easy to cut off the supply by desoldering the small chokes which turn out to be capacitors), the sound chip via a regulator from 12V direct and the network chip also by 3.3V by not directly from the ATX P24.


 

Thank you very much, Mr.riboge and Mr.seger!, posted on June 13, 2010 at 08:45:11
satosong
Audiophile

Posts: 3
Joined: June 7, 2010
There exists a real or net user administrator, doesn't it?
Because of your supports, now, cMP2 is playing music finely!
--See you
satosong

 

Another Breakthrough in SQ - Extreme Mobo Modification, posted on June 13, 2010 at 10:50:31
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
I have been asked to describe mobo modification. Please see my UD2H Mobo modification below.



The solid caps on the Mobo are good, but according to my earlier tests they were slow. So I added some Siemens Sikorel and small MKP caps, an old but very useful trick for diyers. After adding such caps, the Mobo sounds much better.

Siemens Sikorel Cap is chosen, as I found it excellent sounding in power circuit, just behind Blackgate. Others quality caps can of course do the job.

Further to the removal of unwanted chips from the GA H55M-D2H Mobo, I started investigating its PWM power supply circuit. The GA H55M series mobo is found to have the following PWM power circuit:

1 x 4 phase for the CPU Vcore, supplied by P4 12V, current not yet measured
1 x dual phase for the QPI/VTT (2.56A at 1.1V) supplied by P24 5V
1 x single phase for the graphic core (120 ma at 0.65V) supplied by P4 12V
1 x single phase for DDR Ram (160 ma at 1.35V) P24 5V
1 x 0.95V for PCH core supplied by the DDR Ram PS above
1 x 5V for the ITE I/O controller and voltage/fan etc monitor, supplied by P24 5V.
1 x 1.8V for the CPU PLL

This explain why the 5V line is the powerhouse.

I removed the chokes for the DDR Ram and graphic core supplies, then supplied the rams with a 11000mah NiMh battery direct and the graphic core with a similar battery with a variable resistor in between. See pix below:




During boot up, the ram circuit draw 1.5A of current.

After the above substituition, music was so alive right in front of me. More air and clarity, better details, fullness, smoothness and feeling. Everything was better.

I believe the improvement was due to the music file loaded inside the ram and powered by the purist form of supply; when being read the music was noise free. The improvement brough about by the graphic core battery supply was good but not as good when compared to the ram battery supply.

I tried supplying the QPT/VTT with two batteries but in vain.

The investigation is on-going.

 

RE: gdrv off but no change in current consumption, 1394....., posted on June 13, 2010 at 11:12:21
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010
Hi Jack!
What is the current consumption of the CPU (socket P4) at the last configuration (GA H55M-(D)2H BIOS optimised CMP@96K (2 video, 1 sound, 1 network, 1 IDE chip, 2 regulators were removed - I don't see the pci audio card ??? ))?
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

RE: gdrv off but no change in current consumption, 1394....., posted on June 13, 2010 at 11:20:22
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Hi, No P4 12V measurement was taken last time, but it should be 0.46A - 0.18A = 0.28A.


For 0.46A ref. http://www.audioasylum.com/forums/pcaudio/messages/7/74498.html The P4 and P24 12V lines were combined for measurement.


This time P24 12V alone measured 0.18A.

 

RE: gdrv off but no change in current consumption, 1394....., posted on June 13, 2010 at 11:26:27
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010
Thanks Jack! Continue the experiments.It is very useful.
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

RE: gdrv off but no change in current consumption, 1394....., posted on June 13, 2010 at 11:42:44
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Regarding the sound card, I was using a USB DAC.

 

RE: gdrv off but no change in current consumption, 1394....., posted on June 13, 2010 at 12:32:26
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
Thanks, great to see how optimisations reduce power across different voltage lines. To summarise:

  1. default = (12v@0.32A, 5V@3.88A, 3.3V@0.860A) = 26.1 watts
  2. GA H55M-UD2H BIOS optimised (9x100)in CMP = (12v@0.28A, 5V@2.027A, 3.3V@0.698A) = 15.8 watts
  3. same as 2 at 96k = (12v@0.28A, 5V@2.241A, 3.3V@0.714A) = 16.9 watts
  4. same as 2 at 96k (mobo modified) = (12v@0.18A, 5V@2.226A, 3.3V@0.430A) = 14.7 watts


Interesting to see 5V drop is low compared to 12V & 3.3V lines when doing mobo mods. From your extreme mobo modification post, 5V line drives: RAM, H55 chipset, QPI Link, CPU PLL & ITE/Fan/etc.. Gcore and video chips take power from 12V & 3.3V lines. 5V line is most critical supply. Could a simpler mod be done that just provides clean 5V line from linear PSU or battery?

I was wanting to see if video chips on mobo are affected when the actual LCD display monitor is off. Disabling "gdrv" will not switch off display - its an unneeded device driver in Windows. I installed Windows with default BIOS hence I got to see "1394...". In your case enabling it after installation and in cMP mode will cause BSOD.

 

Jack, thanks for leading the way..., posted on June 13, 2010 at 16:56:35
GStew
Audiophile

Posts: 633
Location: NE Mississippi
Joined: September 21, 2001
And showing us this! Computer Audio for the enthusiasts will never be the same again!

I was only expecting info on the motherboard bypasses... and now that's just a bonus for the real treat, motherboard PS mods!

Questions...

1st, what are the values (and in the case of the small blue cylindrical caps and the other non-Sikorel and non-Wima caps, the make) you used?

2nd, in many places you used a combo of Sikorel, blue cap, Wima (the red and green caps), in other places you used different bypass caps, and in some places you just used the bypass caps. Can you explain your philosphy of why which caps where?

3rd, which Black Gates would you use instead (if they were still available)?

4th, are there different types of Sikorels (like there are different types of Black Gates or Oscons)?

5th, got a good international source for the Sikorels?

6th, can you give us some direction on how to duplicate your sleuthing and identify the different PWM circuits? I'm moderately familar with doing this for linear audio circuits, but not at all around motherboards.

BTW, I am pretty sure now that I've resolved the issues with my fully-linear supply (which were not really resolved when I last posted about it). I'll post a tome about it on the "Linear Power Supplies for ATX & P4' sub-thread, but it basically boiled down to a problem with the way I was handling the control signals... Early-on I found out that you could turn off the 5VSB and the POWER_OK signal lines and the computer would still run. Great, so I set mine up to do that and eliminate another potential source of degradation.

But if those lines are not on, the GA-G31M-S2L motherboard will eventually shut down. It may take 2 hours, it may take 1/2 hour, it may run for 4 hours, but eventually it WILL shut down. With those lines on, it seems to run on ok... I've only had it running for up to 12 hours so far, but that's longer than any time with them shut off.

The -12v can be shut off without any issues, however.

Now I've got a lot of tweaking to do with the supplies including trying un-doing some of what I did to try and fix it, but that's another story!

Later!

Greg in Mississippi

P.S. Which Black Gates would you use instead of the Sikorels if you could still get them?
Everything matters!

 

Velleman can power both P4 and Pico on P24 & choosing the right Pico model is important., posted on June 14, 2010 at 01:15:27
Hi Etienne,

I stumbled upon your post and saw you weren’t getting any reply’s, so here’s mine.

1. You can indeed use one (1) Velleman to power both the P4 and the P24 connector.

Note A:
the Velleman can deliver 3 Amps max. Sometimes (- don’t know why only ‘sometimes’- ), this is not enough too start the MoBo with BIOS settings: ‘Optimized defaults’. In case you need to run the MoBo with ‘Optimized’ BIOS settings, just temporarily connect your 230 volt Antec ATX PSU too the P24 pin.

Note B.
Also: if you still have your 230 v (Antec) ATX PSU, you can now use it too power the ‘dirty components’ like USB, HDD ect instead of using the Grannite Digital (GD) PSU’s).

Note C.
Experiment with connecting the 230 v (Antec) switching ATX PSU to another electrical 230 v circuit than your Velleman linear PSU. The (Antec) switching ATX PSU (- as any other switching PSU -) is heavily polluting the 230 v circuit where it takes the 230 V power from. When the Velleman is on the same 230 v circuit, this pollution is degrading the 12 volt output from the Velleman. In my setup it makes a big difference in sound quality when the (Antex) swithing ATX PSU is connected too an other 230 v circuit.


2. The Velleman is connected directly to the P4 and directly to a PicoPSU for the P24.
The Velleman can be easily connected too the P4 by using a P4 extension cable.

Note: be sure to chose the right Pico model (!). A Pico PSU is also a switching PSU and as such, it will give no improvement in sound quality, over any other switching PSU.
However……….. there are some Pico models which leave the 12 volt line untouched, and pass the 12 volt line directly onto the MoBo. When these specific Pico models are fed with 12 volt from a linear PSU, than a sound quality improvement can be expected.
So choosing the right Pico model is important.


Enjoy.
Mark

 

RE: Jack, thanks for leading the way..., posted on June 14, 2010 at 07:07:39
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Thank you! Greg, Answers...

1st, what are the values (and in the case of the small blue cylindrical caps and the other non-Sikorel and non-Wima caps, the make) you used?

I only got 63V 22uf Sikorel, 16V 220uf will be better. The small blue cylindrical caps are 33n Philips MKP filter caps which you may find in filter circuits in some old machines. Old stock no longer under production. Red ones 0.22uf Wima, Green ones 0.01uf 1% Wima cap. I do not feel comfortable by just adding a 0.1 or 0.22uf cap to a E.Cap, so I added a 0.033uf to further improve hi-freq response. My normal practice is to add a 0.1-0.47 MKP cap, further bypassed by a 0.01-0.047 uf.


2nd, in many places you used a combo of Sikorel, blue cap, Wima (the red and green caps), in other places you used different bypass caps, and in some places you just used the bypass caps. Can you explain your philosphy of why which caps where?

It depends on the importance of the PS, balanced by factor of cap size. Eg, I just added simple bypass cap for the ITE 5V and PCIE supply which are considered insignificant to SQ. For the PS around the CPU and ram, they are heavily stuffed with cap combo.

3rd, which Black Gates would you use instead (if they were still available)?

FK perhaps but non that I would use due to cost. Consider the number of caps I used (I have been diying many projects), the use of costy components is not the way to go. Instead, diy skill and knowledge can always bring about good results. Say for example, a battery ps is way better than many costy components. A British U52 or mesh plate 80 tube cannot beat my battery tube HT supply, not to mention costy HT transformers and lower cost of the battery PS. In the current case, if carefully chosen under listen tests, a combo cap can at least perform as good as a single Blackgate or some times better.

4th, are there different types of Sikorels (like there are different types of Black Gates or Oscons)?

As far as I known, Sikorel is an unique series of cap with diffenent ratings.

5th, got a good international source for the Sikorels?

They are widely available in China. The easy way is perhap ebay:

http://cgi.ebay.com/Siemens-Epcos-Sikorel-B41590-220uf-16v-capacitor-10-pcs-/270583478579?cmd=ViewItem&pt=Vintage_Electronics_R2&hash=item3f00083933


6th, can you give us some direction on how to duplicate your sleuthing and identify the different PWM circuits? I'm moderately familar with doing this for linear audio circuits, but not at all around motherboards.

Will do but need more time to examine the CPU 4 phase PWM PS. I will report when the investigation is completed.

 

Choice of H55M Mobo for i3 530 32mn CPU, posted on June 14, 2010 at 07:35:31
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
So far I have tested the following mobos and wish to share my listening experience:

GA H55M-UD2H, GA H55M-D2H, GA H55M-S2H and Asrock H55M-LE.

Asrock is worse in terms of BIOS stablility. Its sound is acceptable but not as good when compared to the GA mobos. Sweet mid, bass is blur, Hi OK. I felt that the PS was not up to speed.

The D2H and S2H are the same mobo, albeit D2H uses all solid caps. They sound similar and are priced the same. The UD2H has 2 OZ copper but 1394 and 2 more ram slots are added. Upon head-to-head comparison, the UD2H is better refined, most probably due to copper sheilding and addition of bypass Caps on my UD2H(i.e. no bypass cap on the D2H).

Upon removal of chips etc from the D2H, its performance shoot up and was on par with the UD2H.

I personally prefer the UD2H because good ground sheilding is an important element to good sounding, plus its potential to do better after removal of chips.

A black horse I consider is the GA H55M USB3. Why? Because it has got an advanced power circuitry. It uses advanced integrated circuits instead of mosfets, which are more costy and implies lower power consumption as well as better frequency response. Had I not found the way to modifiy the mobo's PWM PS, I would have choosen the GA H55M USB3 due to better PS quality.

My personal opinion only, not recommendation.





 

5V line is most critical supply. Could a simpler mod be done that just provides clean 5V line from linear PSU , posted on June 14, 2010 at 08:51:22
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
As far as possible linear supply in place of PWM PS is concerned, the 5V line is no longer critical. The concerns are large current supplies for the QPI (@1.1V) and possibly the CPU(@0.7V). At such low voltage, normal 3 terminal regulator circuit cannot work. A work around is to use a negative voltage to generate low voltage.

Heat disspation is also a concern which is assocaited with the raw DC voltage. A 6V battery supply or 5V power source would be to high as the regulator would dissipate 13W and 12W of heat respectively - a waste of energy and case temp wiould rise. A Low dropout regulator such as LT108X together with a low raw DC voltage, say 3V(or 3.3V Lithium Battery packs), would appear optimial.

I will build two low voltage regulators to test the QPI and CPU.

 

RE: 5V line is most critical supply. Could a simpler mod be done that just provides clean 5V line from linear PSU , posted on June 14, 2010 at 10:44:52
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
Your current approach is superior. I'm looking for an easier way to get say 80% of benefits. Critical chain is:

RAM > QPI link > H55 chipset > PCI or USB


These components all share 5V line. What I'm thinking of is a 5V replacement supply at P24 connector. Possible?

 

RE: FOR JULI@ users: Removing output pulse trans could reveal more transparent sound!, posted on June 14, 2010 at 10:45:07
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
There is a 74HC125 (the SMD 14 pin ic at the bottom near the PCI slot)driving the digital trans. The idea to add a tube buffer, in addition to the 74HC125, does not appear rational to me. To improve sound quality, I recommend the following two options:

1. Replace the SMD 74HC125 with a regular size 54HCxxx, a ceramic version which sound much better than regular 74HCxxx, not to mention SMD version. You can further improve SQ/noise by using small batteries to drive this IC, 3-7V only 15 ma.

2. If a tube buffer is to be used - remove the SMC 74HC125. Trace the origin of the SPDIF signal which should originate from the AKM 4xxx next to it. Tx should be fed to the tube buffer. I recall that Pin 16 is the Tx, download data to confirm this.

With regard to the two options, it matters whether you can provide a clear HT and Filament PS as noise is always an issue associated with tube circuit. The distance between the buffer and the signal source is also a concern, two long will do away the of idea of a good buffer. Too short, the tube can't practically be placed near the sound card or inside the case.

As a diyer, I prefer option 1. In this scenario a tube buffer is not necessarily better. The cost for Option 2 is too high: noise, heat, placement issue. Such discrepancies may outweight improvement to SQ.

 

RE: 5V line is most critical supply. Could a simpler mod be done that just provides clean 5V line from linear PSU , posted on June 14, 2010 at 10:54:44
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Please elaborate more on your idea of a 5V replacement supply at P24 connector. Do you mean replacing the ATX 5V with a linear regulated 5V supply?


I'm think of an idea to use the P24 3.3V to feed a QPI linear regulator, presuming that an ATX PS is to be used. The 3.3V line has very light current loading. By doing so, the P24 5V will be greatly relieved and the interference between the QPI load and Ram etc would be greatly reduced.

 

RE: 5V line is most critical supply. Could a simpler mod be done that just provides clean 5V line from linear PSU , posted on June 14, 2010 at 11:22:22
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
Do you mean replacing the ATX 5V with a linear regulated 5V supply?


Yes. This would power the main audio streaming/signaling chain. Other components including CPU have a secondary role.

Using 3.3V line for QPI is very interesting and would reduce 5V load significantly.

 

thank you very much for your help. However.., posted on June 14, 2010 at 14:26:21
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
Just wanna ask here.. I was failed in running digital tube buffer, is that caused the multiplexer? Hmmm... running tube buffer must bypass that chip?

 

RE: FOR JULI@ users: Removing output pulse trans could reveal more transparent sound!, posted on June 14, 2010 at 16:21:12
theob
Audiophile

Posts: 3180
Location: ann arbor michigan
Joined: November 4, 2000
Wow Jack you are super smart, straight forward and willing to share. You are a gem for this PCAudio thread. Between you and Cics I have hope for humanity. Keep thinking/posting. I just wish you were modding the GA-G31M-S2L.

 

Thanks! theob, Hello Lga 775 RE: ... However.., posted on June 15, 2010 at 07:35:01
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
There is a resistor network between the trans and 74HCxxx for impedance matching, about 75 ohm. I suppose you are taking signal from the trans input side. However, this is not an ideal position to take SPDIF signal from, although it should work with your tube. If it does not, there might be a problem with your connection.

Download data from the link below. See pin layout at page 3, and SPDIF config at page 22. Find the corresponding pins on the 74HCxxx using a multi-meter. Ideally, Tx to grid of tube and DVSS (digital ground) to tube ground.

The AK4114 already has a digital buffer, the use of 74HCxxx is to buffer the SPDIF trans. and optical output. So if you retain the 74HC and add a tbe buffer after the 74HC, you will have three buffers in series. Too many buffers will result in poor square wave response.

By the way, if I were you I would first try direct output from Ak 4114, where SPDIF signal should be relatively pure and untouched. The 74HCxxx altogether with optical etc should be cut off.


Good luck.

 

YES! i've got it. , posted on June 15, 2010 at 15:25:14
lga775
Audiophile

Posts: 38
Joined: October 10, 2009

 

WORLD FIRST SOUND CARD IS BORN!, posted on June 15, 2010 at 15:40:35
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
Proudly presents FIRST TUBE DIGITAL sound card in the world!
Highly appreciated to :
God of digital Mr. Lukasz Fikus (Dr. Lampizator)
Jackwong96
My guru
















 

RE: WORLD FIRST SOUND CARD IS BORN!, posted on June 15, 2010 at 16:22:00
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010
Great! Congratulations! Please construction's details, schematics and what about SQ ? You use an external clock for Juli ?
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

Congratulations! But...., posted on June 16, 2010 at 04:22:36
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
there are a couple of questions (I presume you've copied the spdif tube buffer circuit from the Lampizator site):


1. a tube cathode follower (CF) cannot drive super low impedance satisfactorily, (75 ohm in your case), although a Whites CF with suitable tubes may drive as low as 100 ohm. A good tube circuit design requires that loading of a tube to be 3 to 5 times the Anode load, the same applies either to Anode follower or Cathode follower circuits. This CF circuit has a loading of 150 ohm, and the tube (looks like a Chinese 6N1 or Russian 6H1) has a Anode resistance of a 2-3 Kohms. The load line of this CF circuit is very steep, it has a low voltage swing and high current characteristic, low but not super low impedance. The tube will distort more than a traditional design due to in appropriate cathode loading.

2. I presume the SPFIDF signal is taken from Tx Pin 16. Suppose the CF has a gain of 0.9, the 3.3V SPDIF signal will be reduced to 2.97V and than halfed by the resistor network=1.485V. This exceeds the SPDIF spec. requirement(0.5 to 0.6 V peak to peak voltage, i.e. 1.2V).

The tube buffer circuit is fun but far from ideal. You should conduct blind listening tests with and without the tube buffer, better ask someone to listen rather than yourself. Without tube buffer means taking signal from the Tx with the recommended resistor network on P.22 of the data sheet, with or without transformer. Let us know the result.

 

RE: WORLD FIRST SOUND CARD IS BORN!, posted on June 16, 2010 at 05:45:49
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

> Proudly presents FIRST TUBE DIGITAL sound card in the world!

If you count external soundcards I think I got you beat to the first:

http://www.diyhifisupply.com/node/749

http://www.diyhifisupply.com/node/794

BTW, for the doubters. As standard the Musiland uses multiple parallel Buffers as driver. Comparing the signal from that with the Tube Stage shows the tubestage has a much faster risetime and a very clear trace.

Certainly the signal is much better. How much that impacts on sound quality - who can say, who wants to say? Subjctively, using a DAC with a cirrus logic receiver the Tube stage plus musiland sounds cleaner and less edgy, compared to the already heavily modified unit which normally gives a quite clean trace already.

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: Congratulations! But...., posted on June 16, 2010 at 05:46:17
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
1. i am not sure bout it. its abit technical however, one of my friend was using sony transport he find out the sony transport has this transistor buffered circuit. After that, he also follows digilampizator in his another philips CD Player just that with positive result!

2. Yes the output is higher, but it doesnt effect the sound. my journey of this was:-
i.) Signal out from the output trans. "Sound is normal"
ii.) Signal without the output trans. (impedence measure was 100ohm!) More revealing)
iii.) Signal with multiplexer bypass with 75ohm resistor to ground. "Very transparent!"
iv. )Signal from TUBE buffered circuit. "This is where magical inspiration take place, similar transparency as without multiplexer but with more liquid. perfectly defined highs, deep and powerful precice bass, huge stage, you can really pinpoint the instruments in a orchestra, different is night and day. Its not upgrade of the sound but like changes entire sound.

 

RE: WORLD FIRST SOUND CARD IS BORN!, posted on June 16, 2010 at 06:16:56
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
Clock: Modded LCLOCK XO3 with dedicated power supply.
SQ
i.) Signal out from the output trans. "Sound is normal"
ii.) Signal without the output trans. (impedence measure was 100ohm!) More revealing)
iii.) Signal with multiplexer bypass with 75ohm resistor to ground. "Very transparent!"
iv. )Signal from TUBE buffered circuit. "This is where magical inspiration take place, similar transparency as without multiplexer but with more liquid. perfectly defined highs, deep and powerful precice bass, huge stage, you can really pinpoint the instruments in a orchestra, different is night and day. Its not upgrade of the sound but like changes entire sound. This is the way for a computer transport to inject musicality like CD transport!
in fact audio note does this.

 

In other words, signal quality matters greatly, posted on June 16, 2010 at 09:28:58
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
Quote:

Question: What makes the tubed usb to spdif converter better the non tubed version?
Answer:
The tubed output stage operates differently to the solid state logic one. The Tube stage operates as linear Class
Amplifier and does not "saturate". The normal logic IC based output buffer circuitry operates in "saturation" meaning
it is slower to react to signal changes. The Tube stage also has much less input capacitance than CMOS logic IC's, so
the rise-time of the signal is faster.

The technical result is a signal output that is cleaner and closer to the theoretically "ideal" SPDIF Signal.

As a result the DAC's SPDIF receiver can recover the signal and clock with less jitter, in technical terms. This in turn
generally produces a better, more natural and non-fatiguing sound.


Sreaming audio efficiently is a key design goal for cMP².

 

Need a pdf document with detailed instructions, diagram and pictures, posted on June 16, 2010 at 09:32:36
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
Congratulations. Yet another step forward!

I'll put this on our site in Advanced section under Juli@ mods.

 

Need some time.., posted on June 16, 2010 at 09:47:04
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
i am currently busy with my academy exams... i've been struggling with this project for a month plus.. until jackwong96 and Dr.Lamp told me that has to bypass the multiplexer.

 

RE: In other words, signal quality matters greatly, posted on June 16, 2010 at 10:01:27
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
I'm tube inclined and using DHT in my DAC as well as the entire system. I like the idea of a tube SPDIF buffer, however, the tube buffer circuit in question fall short of a good design. This is simple electronics but no magic. I believe the true potential of a tube SPDIF buffer is yet to be unveiled, with improvement of circuitry, such as White's Cathode Follower.

 

For SPDIF? Of course it does..., posted on June 16, 2010 at 10:35:22
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

Another factor is the current that the SPDIF output circuitry draws dynamically if it is used.

Driving a minimum capacitance short twisted pair and a cathode follower tube draws much less current than a resistive divider.

All in all SPDIF connections are not easy to get right, but they are what everyone seems to insist on using...

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: In other words, signal quality matters greatly, posted on June 16, 2010 at 10:44:53
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

> I like the idea of a tube SPDIF buffer, however,
> the tube buffer circuit in question fall short of a good design.

How do you know? Did you see and analyse my schematic for the module diyhifisupply sells? They only came back from the factory.

> This is simple electronics but no magic.

Yup. We just need around 0.5V PP into 75 Ohm. That is 6.66mA Peak-Peak, so we need to have a bit more than halve that as quiescent current, not very hard to do.

> I believe the true potential of a tube SPDIF buffer is yet to
> be unveiled, with improvement of circuitry, such as White's
> Cathode Follower.

I tested my buffer as under 1pS Risetime including the the drive signal from the FPGA. How would you like to improve this?

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: In other words, signal quality matters greatly, posted on June 16, 2010 at 11:38:47
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Thorsten, Your tube buffer design is perfect! I believe it can drive a 75 ohm headphone too. In such case, not much I can contribute.

 

RE: In other words, signal quality matters greatly, posted on June 16, 2010 at 11:44:40
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

> I believe it can drive a 75 ohm headphone too.

It can. To 0.5V Peak-Peak. Or 4mW RMS. And I doubt the output transformers are capable to go down into the audio range...

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: In other words, signal quality matters greatly, posted on June 16, 2010 at 12:24:56
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
hi there... mind to show your tube circuit of buffer stage?

 

RE: In other words, signal quality matters greatly, posted on June 16, 2010 at 21:08:56
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

> hi there... mind to show your tube circuit of buffer stage?

The circuitry is applied to a commercial product, so I am not at liberty to disclose it, sorry.

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: In other words, signal quality matters greatly, posted on June 17, 2010 at 10:08:41
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
Those are impressive risetimes at 1ps! Here's the digital waveform of a 1kHz tone (at 96000 Fs) done a few years ago:



Risetimes well into 10s of ns together with over- & under-shoot.

Due to commercial obligations you're unable to share your circuit design, however it would be interesting to see equivalent from your DAC's SPDIF output.

 

RE: In other words, signal quality matters greatly, posted on June 17, 2010 at 10:17:57
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

I need to take a new trace when I get to test another unit. But the traces shown above are not that good at all.

I previously posted on my modifications for the Musiland Monitor 01 USD, which includes the traces from my mods without the tube section.

http://www.audioasylum.com/forums/pcaudio/messages/6/66884.html

The tubed output stage does better. The figure comes from the NEC Digiscope. I did a doubletake too, but the numbers came up like this.

I think it calculates the rise time from 30% to 70% around the zero crossing. Still, the output is very square, a lot better than the above.

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: In other words, signal quality matters greatly, posted on June 17, 2010 at 10:45:13
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
I used a cheap Creative soundcard (which outputs TTL and yes its crap) for that measurement (using ELAB-080 DSO). Your Musiland trace looks good and even better after mods.

A tube output stage makes a lot of sense. Given that BMC encoding is used for both S/PDIF & AES/EBU and they can be readily converted to/from, can the tube design be extended to AES/EBU?

 

RE: In other words, signal quality matters greatly, posted on June 17, 2010 at 11:20:28
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
hey Bro, remember dr. fikusz had tried on using AES/EBU however the result is NEGATIVE..

What he said:
I am sure that a single ended connection is best for S/PDIF signal. I do not like toslink and I don't like AES/EBU either.
The "pro" looking AES/EBU connection is using XLR and it looks OH SO PROFESSIONAL WOWIE ZOWIE. We buy by the eyes. But the AES/EBU is not invented to be better. It is invented to be LONG DISTANCE.
The RS422 industrial data transmission from which AES/EBU derives can travel as long as 1,8 km (over one mile) on the twisted pair balanced cable. The S/PDIF in coax cable can travel up to few single meters. THAT IS THE DIFFERENCE. But the S/PDIF signal on both ends exists ONLY as simple single ended asymetrical signal. We must make it balanced artificially by means of adding a balancing transformer which badly distorts the signal. Then we use in our systems one metre cable (not one mile !) and we must use de-symmertization transformer on other end again. That's two unnecessary transformers, two too many for me.
In analog systems, the ballanced XLR has more meaning - as described HERE, but in digital - the signal itself is never trully ballanced, it is the sending media that is ballanced to make long distance possible.

so why is the AES/EBU sounding better on many transport/dac combos ?

Answer is easy. Because the S/PDIF on all transports that I have seen, and I have analyzed about 40 different ones - is made wrongly and it uses an ugly separation transformer as well. So in that scenario - S/PDIF can not beat AES/EBU because they both have the biggest limiting factor - the transformer."

Like my previous post, removing the pulse trans will help in sound revealing transparency.

 

CONFIRMED, removing trans will give you the sound!, posted on June 17, 2010 at 11:25:54
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
i.) Signal out from the output trans. "Sound is normal"
ii.) Signal without the output trans. (impedence measure was 100ohm!) More revealing)
iii.) Signal with multiplexer bypass with 75ohm resistor to ground. "Very transparent!"
iv. )Signal from TUBE buffered circuit. "This is where magical inspiration take place, similar transparency as without multiplexer but with more liquid. perfectly defined highs, deep and powerful precice bass, huge stage, you can really pinpoint the instruments in a orchestra, different is night and day. Its not upgrade of the sound but like changes entire sound. This is the way for a computer transport to inject musicality like CD transport!
in fact audio note does this.

 

Some listening demo video of the TUBE SOUND CARD., posted on June 17, 2010 at 11:32:42
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
due to the resource limitation, i just do anything more than capturing using my cheap HandPhone. U don't listen to the recorded video quality.

Hmmm, however i am truly blive u can simply compares the flow of music without looking to in-depth details.
This is how a music flow should sound.

I don listen michael jackson in CD format b4 i tube the digital, this is bcos Michael Jackson sounds not it shoud be comparing to VINYL that i have listen.

BUT.! listen here, this tube stage brings back the life of music. Mentioned that it realigns the ingredients of MUSIC.
So... Yes i do enjoy listen to more music!


 

RE: In other words, signal quality matters greatly, posted on June 17, 2010 at 16:45:45
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

> can the tube design be extended to AES/EBU?

Sure, it just needs a different wiring up. This will all go into the Manual.

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: In other words, signal quality matters greatly, posted on June 17, 2010 at 16:57:31
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

> hey Bro, remember dr. fikusz had tried on using AES/EBU
> however the result is NEGATIVE..

Yes. But that this mean it is universally applicable?

Generally when done to equal levels of implementation, AES/EBU usually sounds better.

> But the S/PDIF signal on both ends exists ONLY as simple
> single ended asymetrical signal.

Actually, wrong. Almost all receivers out there have balanced inputs.

> We must make it balanced artificially by means of adding a
> balancing transformer which badly distorts the signal.

Wrong again. AES/EBU can be made "transformerless", secondly, the traces shown from the Musiland (as well as the Tube Stages I designed) use transformers. Transformers only distort the signal if used wrongly.

The key to understanding is that all these interfaces are radio-frequency designs. We can make wireless routers that work reliable at 2.4GHz. The 25MHz needed for SPDIF and/or AES/EBU are actually quite easy, this merely Shortwave radio frequencies.

> Then we use in our systems one metre cable

Ouch. A 1 meter coax cable is precisely the worst length or an SPDIF cable.

> Like my previous post, removing the pulse trans will help
> in sound revealing transparency.

Actually, you may wish to read the blog posts over at www.diyhifisupply.com. You are right insofar - removing the original tranformers (which are basically inappropriate) improved sound quality.

HOWEVER, correctly implementing some higher quality transformers improved the sound quality even further.

Then getting rid of the two daisy chained inverters that drive the digital outputs on the Musiland and using instead a linear tube stage while retaining the transformer produced further improvements.

The bottom line - as I often say, it is not what you do (e.g. use transformers in SPDIF or AES/EBU interfaces) but how you do it that makes the difference.

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: Thanks! theob, Hello Lga 775 RE: ... However.., posted on June 18, 2010 at 01:05:25
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Hi Jack

Quote:
"Ideally, Tx to grid of tube and DVSS (digital ground) to tube
ground."


Can we use this direct connection out to the BNC socket? Or need to replace 74HCxxx with 54HCxxx and take the feed from there?

TIA

 

RE: Thanks! theob, Hello Lga 775 RE: ... However.., posted on June 18, 2010 at 07:41:17
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Hi TIA,

Of course you can. You may also disconnect the 74HCxxx by lifting the corresponding pin off the PCB (add solder, lift pin and suck off solder). In addition, lifting pin 14 (upper last pin near the back metal plate) will disconnect the power supply. As the Ak4xxx already has an internal buffer, adding one more after it may not improve the output waveform, although the property of signal may vary according to the second buffer used. You need to perform listen test to find out which option is better.

A suitable resistor network, such as the ones given on the datasheet, should be used. Thereafter a cap or trans before your BNC.

Good luck. Let us know the result.

Jack

 

RE: In other words, signal quality matters greatly, posted on June 18, 2010 at 08:31:52
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Hi Thorsten

> HOWEVER, correctly implementing some higher quality transformers
improved the sound quality even further.

What output transformer would you recommend for the Juli@ to replace the Hanrun?

Regards

 

RE: In other words, signal quality matters greatly, posted on June 18, 2010 at 09:26:29
Thorsten
Manufacturer

Posts: 4209
Location: Somewhere nice on planet dirt
Joined: September 25, 1999
Hi,

> What output transformer would you recommend for the Juli@
> to replace the Hanrun?

First, I do not know the Juli@ first hand, I have no idea of circuit implementation etc. So it is impossible to make an informed suggestion.

Second, simple transformer swapping gets you nowhere fast.

You need to be able to find a transformer that is sufficiently consistent in production (harder than you think) and characterise it's parasitic (unwanted) behaviours and then design a circuit that gets the best out of this transformer.

For example people ask me "Which transformer do you use for your musiland mod's, I want to try them."

My answer is always:

"Knowing Brand and type will not help you, unless you know my exact application circuit, which is not for public dissemination. And to avoid negativity from people using the transformers wrong and then complaining they are not good and this reflecting back badly on my designs I'm not telling the first part either."

I hope you understand.

Ciao T

Ciao T
Thor

At 20 bits, you are on the verge of dynamic range covering fly-farts-at-20-feet to intolerable pain. Really, what more could we need?

 

RE: Some listening demo video of the TUBE SOUND CARD., posted on June 18, 2010 at 10:47:00
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
Good music flow! I'm with you, in Hong Kong.

 

RE: Feedback on DDR3 DRAM timings, posted on June 19, 2010 at 04:59:55
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
I have the same experience with the D2H mobo where bypass cap was not added, but not so with the modified UD2H. The difference in speed can be heard. This concerns the frequency response of PWM ps of the mobo, which is too slow responding to aggressive Dram timings.

 

Okay, I'm starting to get exicited!, posted on June 19, 2010 at 08:37:03
Julien43
Audiophile

Posts: 2828
Location: Western NC... Shelby
Joined: May 5, 2001
I've received my Gigabyte G31M-ES2L MB, E7500 CPU and the Zalman case prescribed in cics hardware list. (BTW, The Silver HD160XT is on sale at Newegg for $299 +shipping)

I have a 1Gb stick of Kingston’s HyperX DDR2 800Mhz RAM on the way. I haven't ordered any HDDs yet as I'm a little taped out and I want to try and get the best solution considering cost and SQ (SQ being the higher priority).
I understand that the less power consuming 2.5" lap top drive should perform better, but I don't know what else, besides capacity I should be looking for.

I have also held off on the PSs as I wanted to get some feedback concerning the different approaches of using the Granite supplies with an ATX or using 2 ATX supplies. I don't which one is the best choice or if there is even a consensus on this.

Oh yeah, There is the concern of using minlogon with XP Pro. I have read some post that make me want to turn and run but I do want to squeeze every last drop of performance out of all the hard work cics and you other loonies of this Ward have given to this commendable project.

I'm sure there are many other ares of implementing cMP that are as deserving of attention than just the few I mentioned.

Please give me any feedback you think will help me in my pursuit to fulfill the full potential of the cMP. I look forward to your responses.

I'm sure this is not the last time that I will be asking for help as my knowledge of computers is very limited.

Thanks for taking the time to read my post.



Julien

 

PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 19, 2010 at 16:31:14
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
I hope you will like it and I am happy of contribute and bring us to a better enjoyment!

Please let me know if there is any correction.

GOOD LUCK!

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 19, 2010 at 17:20:01
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010
The file is successfully downloaded. Thanks!
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

RE: WORLD FIRST SOUND CARD IS BORN!, posted on June 19, 2010 at 18:03:51
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010



You're sure you have connected LCLOCK XO3 correctly?
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

Please switch to new 32nm technology (Intel Core i3-530, ...), posted on June 20, 2010 at 00:08:43
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
Improvement over previous 45nm technology is very significant and well worth the extra effort! I'll be changing the site to these new specifications:

  1. Intel Core i3-530 ($115)
  2. Gigabyte GA-H55M-UD2H ($97)
  3. Kingston ValueRam DDR3-1333 @1GB (30$)


Don't know if Newegg will allow for swapping. Also make sure your CPU cooler supports the new 1156 socket.

BIOS details and more can be found here, here and here.

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 20, 2010 at 04:27:02
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Me cannot download. Can anyone email the file instead at smicyta@singnet.com.sg?


tia

 

RE: WORLD FIRST SOUND CARD IS BORN!, posted on June 20, 2010 at 05:51:34
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
wow.. thanks for ur concern, hmmm i think it should be correct but without the 0.1uf coupling cap. Does that a matter?

 

RE: Please switch to new 32nm technology (Intel Core i3-530, ...), posted on June 20, 2010 at 06:27:23
Julien43
Audiophile

Posts: 2828
Location: Western NC... Shelby
Joined: May 5, 2001
Thanks cics...
That's not a problem at all. The only problem I see is waiting for, downloading, printing and reading the new manual a half dozen times, so that I can start to feel comfortable moving forward with the project. This will be, by far, the most expensive DIY project is have yet to attempt.

Do you have any idea when you will be able to update the documentation on the cMP2 website? I don't mean to rush you. I just don't want to try to search the forum for information about this build. The fact that you had all the documentation together was one of the reasons I decided to "Go For It"

I have very limited computer knowledge so I'm looking for anything that can give me a "leg up" on actual implementation of your masterpiece.

Thanks for your feedback. I already have the new hardware on the way. Are there any other thoughts you can share with me about the other concerns I mention in my initial post?

Thanks for your response and patience with novice like myself!

Julien

 

RE: WORLD FIRST SOUND CARD IS BORN!, posted on June 20, 2010 at 08:18:56
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010



OK. I nevertheless would mount the capacitor 0.1 µF.

Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 20, 2010 at 17:58:28
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Download finnaly successful. Thank you for unselfishly sharing your hardwork.

 

RE: Please switch to new 32nm technology (Intel Core i3-530, ...), posted on June 20, 2010 at 18:41:35
Julien43
Audiophile

Posts: 2828
Location: Western NC... Shelby
Joined: May 5, 2001
Would this make an appropriate cooling tower for the i3-530?

(embedded link)




I would really hate to burn up a brand new processor

Julien

 

RE: cMP - the open source high-end Memory Player, posted on June 20, 2010 at 19:50:41
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Hi Mihaylov

Just to check if GND of LClock XO3 feed cable is soldered to Pin 2 of the 10 pins header.


Regards

 

RE: Please switch to new 32nm technology (Intel Core i3-530, ...), posted on June 20, 2010 at 23:39:05
cics
Audiophile

Posts: 1320
Joined: November 9, 2006
That cooler will do just fine when BIOS setup has low voltage and frequency. I recommend using default cooler with fan if you don't set BIOS initially otherwise with this cooler installed make sure BIOS has voltage of at least 0.85000 and set freq to 9x (133 = 1.2GHz).

 

PSU recommendations remain the same?, posted on June 21, 2010 at 00:30:51
Bibo01
Audiophile

Posts: 648
Joined: December 18, 2008
Antec EarthWatts for P24 and 1" PSU for the rest?

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 21, 2010 at 08:02:13
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
I done some calculation of the circuit according the tube data and textbook reference:

6n14P data: http://frank.pocnet.net/sheets/113/6/6N14P.pdf

mu=25 S=6.8 Ra = mu/S = 3.67K


Output impedance of a cathode follower

Rout = Ra / mu+1

= 3.67K / 26 = 141 ohm

Voltage gain of a cathode follower

Where Rk= (75+75)=150 ohm

V= (mu * Rk) / (Ra + (mu+1)*Rk) = 3750/7570 = 0.495


With a 3.3V input, this output will be about 0.4V PP.


I built the circuit to test its performance. Since I don't have any 6n14P, I used an equivalant tube, ECC84, instead.



Below pix showed the signal at the input (upper trace) and the tube output
(lower trace). The singal was drawn directly from the FPGA and hex inverter(74hcxx)was removed. No loading was applied to the tube output.





Below pix showed the signal at the input (upper trace) and the tube output
(lower trace) wuth a 75 ohm resistive load applied.





Great! This tube buffer can handle a 75 ohm load, albeit at a reduced output(about 0.32V PP). Not bad for such a simple buffer circuit.

By the way, LGA 775, there are some mistakes on the power supply circuit.

The bridge rectifier was not correctly connected, and AC is applied directly to the caps.

I do not know the application of the voltage stablizer in your circuit as it was placed in series with the B+ rail. It is supposed to be connected in parellel with the PS so as to stabilize voltage. It acts like a shunt regulator and a resisitor needs to be put in series with it whereas the cap in parellel should suitably reduced. More, if it is intended to be used as a shunt reg. the rating of 75V does not seem sufficient for this circuit. 125V would be better. please clarify.

Finally, the filament needs a voltage reference. In this case, reference to the ground.

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 21, 2010 at 10:46:32
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010
Hi Jack! Could you show the oscillogram of standard spdif output without the tube buffer (stock version of juli, musiland etc.) to see advantages of the tube buffer.

Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

RE: Please switch to new 32nm technology (Intel Core i3-530, ...), posted on June 21, 2010 at 11:31:25
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010










I think these coolers (Thermalright AXP-140RT, Thermaltake ISGC-400, Scythe Kabuto/Zipang 2) are more preferable to the case Zalman HD160XT.
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

Much Thanks! I need all the help I can get!! /nt\, posted on June 21, 2010 at 17:24:05
Julien43
Audiophile

Posts: 2828
Location: Western NC... Shelby
Joined: May 5, 2001
nt
Julien

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 22, 2010 at 08:29:41
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
The tests continue. The below pix shows a stock Musiland 01 USD with its BNC output connected to a 75 ohm (3-feet) cable, terminated at the other end with a two 150 ohm resistors in parellel. Not bad for this cheapee! Although noise is a bit high.




Next, a waveform test for symmetrical output. A saw wave is used. Upper trace 3.3V PP to the input of the tube buffer, the lower trace about 0.4V PP take at the output. See the voltage difference between the positive and negative swings of the lower trace.




The below pix shows the output swing at about 1V PP, the diffference is more profound. The negative swing is clipping. The buffer distorted. If you look carefully at the last pix on my previous post, you will notice the same.






What next? As a loading of 150 ohm is extremely low for the tube which has a RP of 3670 ohm, the cathode resistor value should be increased....

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 22, 2010 at 13:10:31
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
hi there.. i was quite shocked when i look at ur measured scope that there is some fluctuating. hmmm just wanna report that yes the documentation has a mistake at the AC-DC rectification. After the 0C2 tube there is another shunt 0.1uf bypass capacitor.

Also i measured my B+ i got 115V nominal with +/-1% voltage ripple. Absolute max voltage swing was +/-2V. Inital startup B+ was about 131-132V.

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 22, 2010 at 17:45:53
smicyta
Audiophile

Posts: 125
Joined: February 19, 2010
Hi Jack

Great follow-up on the design by lga775. Hope your input will result in a better design for the tube buffer.

>The negative swing is clipping.The buffer distorted.

What is the significance of this distortion? Will it manifest in incoherence in the music?

>What next? As a loading of 150 ohm is extremely low for the tube which has a RP of 3670 ohm, the cathode resistor value should be increased....

Any suggestion to address this shortcoming?

Best Regards

 

RE: Please switch to new 32nm technology (Intel Core i3-530, ...), posted on June 23, 2010 at 17:59:46
Julien43
Audiophile

Posts: 2828
Location: Western NC... Shelby
Joined: May 5, 2001
I'n S00ooo.. glad I posted before I began the build. It would have been a shame to put up the cash and effort to find I had a sub par build.

I've shipped the MB and processor back to Amazon and have the Core i3-530 , Gigabyte GA-H55M-UD2H and Kingston ValueRam DDR3-1333 ordered from NewEgg. I've also bought a Juli@ card. I have to hold off on the PSUs and HDDs until I can free up some more cash.

I have copied and pasted all the pertinent information from the posts that you linked. I am going to try and organize them into a procedure and see what I can come up with.

I know just enough about computers to be dangerous. I'll do the best I can and try keep the smoke inside ;~)

Thanks for all your hard work and help! I never thought I'd be able to better my Lambda II (with my budget) until I took notice of your cMP!!

Julien

 

Revised A New power circuit., posted on June 23, 2010 at 18:47:29
lga775
Audiophile

Posts: 38
Joined: October 10, 2009


Did tried with Resistor as CRCLC, very bad ripple filtering capability.
Sound is not good. when u use metal film will sound brighter and sharp.
Using carbon will sound not transparent.
although B+ has got 75V, but still better than previous circuit.
Higher capability of filtering ripple and more clean sound.

 

How about when using the I2S "output" -, posted on June 25, 2010 at 11:09:17
Posts: 3040
Location: Atlanta
Joined: December 15, 2003
is this transformer involved here?

Could this explain the good reports of using I2S with JULI@?

 

HELP : minlogon is obstructing my new software, posted on June 25, 2010 at 14:12:49
play-mate
Audiophile

Posts: 948
Joined: November 21, 2008
dear community

that minlogon is a pain sometimes is well known, but the ID identification of my new "acourate" roomcorection software gives me following error msg.:

NTVDM-CPU has identified an unallowed instruction.

...any idea what may cause that.
I hate the idea to reverse all the configurations.

kind regards
Hysolid // Mytek Brooklyn // Spectron Musician III // Analysis Audio Omega

 

RE: How about when using the I2S "output" -, posted on June 25, 2010 at 16:36:04
lga775
Audiophile

Posts: 38
Joined: October 10, 2009
I have heard good results of sound that using I2S compare to SPDIF, but it is not meant for a long length.. I will try I2S using CAT7 ethernet cable later and compare the performance.

if u are using the I2S output then, this has nothing to do with the transformer or SPDIF.

 

RE: How about when using the I2S "output" -, posted on June 25, 2010 at 18:26:43
theob
Audiophile

Posts: 3180
Location: ann arbor michigan
Joined: November 4, 2000
I use about 1.4 meters of i2s using 75 ohm teflon coaxial cable. The outer shield of all cables are grounded both ends....juli@ and buf32s. Sounds very transparent.

 

Also make sure, posted on June 25, 2010 at 23:04:40
steppe
Audiophile

Posts: 641
Joined: September 28, 2006



that after you have the cooler installed, it won't stay in the way of the top cover of Zalman case. Mine, unfortunately, does, so I want another one, but only after I decide to build my next cmp with 32 nm processor.
The Ninja on the photo doesn't fit well, no matter how efficient.
Steppe.

 

Thanks Steppe!, posted on June 26, 2010 at 03:24:57
Julien43
Audiophile

Posts: 2828
Location: Western NC... Shelby
Joined: May 5, 2001
I thought of just that same consideration after reading Mihaylov's post and recommended CPU coolers.

The one problem I'm having is that the sites where I can find those particular coolers don't list them for the 1156 socket.

I'll probably have to email the manufactures to find out if there are adapters for the 1156 application. In the mean time, if you happen to locate one please post and let me know. I'm not getting into too much of a hurry as I still need to obtain some HDDs and PSUs.

Thanks Again!!

Julien

 

RE: Thanks Steppe!, posted on June 26, 2010 at 04:40:00
The Noctua NH-C12P SE14 is the best built heatsink I've ever used, and goes on solidly and easily on 1156 or 775 or 1366 mobos (also good for AMD mobos, but I haven't tried it there). Vertical fins are good for passive cooling, especially if you cut a vent in the top of the case for airflow. Downside, it's a bit costly.

 

RE: PDF DOCUMENTATION OF DIGITAL TUBE STAGE!, posted on June 26, 2010 at 09:21:29
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
>The negative swing is clipping.The buffer distorted. [What is the significance of this distortion? Will it manifest in incoherence in the music?]

I havn't conducted a listen test on the distorted signal, but I guess I would not like it.

>What next? As a loading of 150 ohm is extremely low for the tube which has a RP of 3670 ohm, the cathode resistor value should be increased....

[Any suggestion to address this shortcoming?]


The tests continue. The ECC84 did not give a good voltage swing and its output impedance was high. Therefore, I switched to ECC88, a more popular tube with a lower Rp. Used as a cathode follower, it has an output impedance of 78 ohm (almost one half of 6n14P) under the given configuration and a better output swing. The ECC 88 is suitable for low voltage applications (in the old days I've built an ECC88 pre-preamp using 24V B+ for my mc cartridges), the value of cathode resistor is relatively low, therefore, 150R of cathode resistor is very suitable for the application and resulted in a better headroom.


Below two pix shows a ECC88 buffer @90V with a cathode resistor of 75R + 75R. The output was taken from the lower 75R where it was loaded with a 1.5M video cable terminated with a 75R resistive load on the other end. I've tried increasing the cathode resistor value using a negative supply rail which resulted in better voltage swing but not lower output impedance or improved waveform. I've also tried using a digital trans. but the result was not satisfatory.

First one, SPDIF signal locked




Second one, SPDIF working with 1Khz sine wave signal. This one looks very much like the "AFTER" pix in the PDF posted by lga775, albeit more symetrical.







In my last post the output waveform of the ECC 84, with no load applied, was respectable in terms of square wave performance, but not its symetrical swing. This was improved by the use of ECC88. However, when loaded with a 1.5M cable and terminated with a 75R resistor on the other end, the output of ECC88 ran out of gas and the square wave was rounder than it should be. My attenpt to put a digital trans. at the O/P was not satisfactory too. The reason for this, I believe, was because the output impedance of the tube was not low enough to drive the load. Although the ECC88 cathode follower has a respectablely low output impedance, it was using its maximum strength to drive a 75 ohm cable terminated with 75R resistor (a capacitive load (of the cable) + resistive one of the R), not to mention adding an inductive load (digi-trans.). Consider this situation, would someone be satisfied with the performance of a set up with an amplifier of 8 ohm output impedance driving a 8 ohm speaker? No. I would not. A much lower output impedance would be required to drive a 8 ohm speaker to satisfaction.

What next? I need a tube buffer with a super low output impedance. The White Cathode Follower (WCF) immediately comes to mind. See this link:
http://www.tubecad.com/2006/10/09/cathode%20followers.png


So I built a WCF circuit using an ECC88. It has a gain of 0.97 and an output impedance of around 10 ohm. You can Google for info on WCF. The inherent uses of WCF were video buffer in the old days and headphone amp. Since it has a much higher voltage swing, a resistive network was used to bring the signal down to SPDIF level. The resistor network was connected to a digital trans. before output to the 1.5m video cable(terminated with 75R resistor).

Below pix : WCF o/p SPDIF signal loack @96K





Below pix : WCF o/p working with 1Khz of sine wave.




Not bad in terms of square wave perforance, although rise time is marginally slower than the original signal. There was slight undershoots which may be improved upon refinement of the circuit.

After some burn in, I will talk about the sound quality of the three configurations, i.e. Two tube configs (CF & WCF) and the original 74HCxxx output.

 

RE: How about when using the I2S "output" -, posted on June 26, 2010 at 11:34:38
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
theob, Happen to see your config of I2S. I think you would benifit more by disconnecting all ground shields at the BUF32 and use a seperate wire for all ground connections. The reason for doing so is to remove capacitive loading of the cables - the inputs at the Buf32 will see much lower capacitance because the shields will not be actually loaded but still perform their shield function.

 

RE: How about when using the I2S "output" -, posted on June 26, 2010 at 14:44:25
theob
Audiophile

Posts: 3180
Location: ann arbor michigan
Joined: November 4, 2000
I think you would benifit more by disconnecting all ground shields at the BUF32 and use a seperate wire for all ground connections.


Hi Jack I understand disconnecting all grounds at buf32s but what does use a separate wire for all ground connections mean? Can you say a little more about this?

 

RE: How about when using the I2S "output" -, posted on June 26, 2010 at 17:45:37
jackwong96
Audiophile

Posts: 219
Joined: April 20, 2010
After disconnecting all grounds at buf32s, the input could no longer make reference to the ground signal and the card would not work at all. A seperate grounding connection is required, therefore, an indepenent wire is used to link the grounds at both cards(this provides physical connection for the three original ground connections, only one ground wire is required)


Like this.


......................========================================
75R cable = +++++++++++++++++++++++++++++++++++++++++++++(Hot)
......................========================================(Gnd)

Coxial cable grounded at output side. Input ground disconnected.

Coxial Cable
.............==================================================
I2SO/P+++++++++++++++++++++++++++++++++++++++++++++++++++++++BUF32in
I2SGnd====================================================

Connect the digital grounds of both cards by another wire:

Ground Wire
I2SGnd--------------------------------------------------BUF32Gnd

 

RE: Thanks Steppe!, posted on June 26, 2010 at 20:23:42
Mihaylov
Audiophile

Posts: 355
Location: Moscow
Joined: March 11, 2010
NH-C12P undoubtedly is the good cooler because of the silent, effective and expensive fan. But the fan is not required to you, therefore you simply overpay for a cooler approximately 20$.
Serge.
http://cmp2-mihaylov.narod.ru/

My cMP2: Windows XP SP2 Ru, GA-H55M-UD2H, i3-530, Corsair CM3X160C9DHX 1GB, system drive - Transcend IDE FLASH MODULE TS2GDOM40V-S FAT32, ESI Juli@, full linear PSU, NAS - WD My Book Live

 

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