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In Reply to: RE: cMP - the open source high-end Memory Player posted by cics on December 30, 2007 at 05:42:01
See section 4.14 in AOB Computer Transports version 0.3 for more details.
Research on Operating System Jitter shows significant dependencies for performance (in massively paralleled computing systems) and for effective realtime processing. OS jitter refers to timing errors caused by OS for scheduled process / thread events. Key to reducing such jitter is eliminating OS bloat, an unfortunate Windows trait. For technically minded, here's useful research material from IBM:
Feedback needed.
Follow Ups:
More extensive testing shows better performance without this setting.
Hi,
I added the "nopae" line and I can now lower voltage to 1.01875 but I feel I've reached the limits of my system. The slightest move of the mouse and I get glitches at the output. Also the first second of playback is not always very clean. Is it due to cPlay automaticaly starting playback right after loading songs into ram ?
I have the "old" version of the Gigabyte mobo, running at 170MHz with 2X1GB HyperX and output at 96k. The sound quality is very very analogue with deep bass, smooth mids, and incredibly fast response.
What do you think would bring my PC back to a little comfort zone without damaging the sound quality ? A little higher clock or voltage ?
I still use the .979 driver for my Juli@ might upgrade to 1.23 soon, is it worth it ?
Next step for me would be the sound card cond mod, then the mobo cond mod.
Has anyone using 192K changed the spdif connector to something better like a Canare 75ohm RCA or even a BNC connector ? Have you soldered it right to the board ?
I'm using 96K and did not yet choose between coax or optic.
the following mod for the juli@ dates back from 2005, and was posted by marcello on another forum.
_
"Upgrading digital section:
Locate a good "audiophile"clock oscillator manufacturer. There are multiple offers available on the internet, varying from LC, Audiocom, etc. In NL, Audioart is making a VERY good clock but I'm not sure if they are selling it separately. If not I can intermediate.
I will come with my own clock this summer. 12V and the lowest noise and jitter you've heard of.
Two clocks are needed, one for 22.5792MHz and 1 for 24.576MHz. Replace the existing crystals (x1 and X2)with the corresponding clock oscillators. Power these external clock oscillators by a very good linear supply, or even a lead acid battery if the required voltage is 12Vdc.
Solder a 220uF/10V SG or SH OsCon capacitor from U6, AKM's 4114 chip AVDD pin 38 to ground. Best is to do this on the underside of the board, across BC25. Negative to the solder pad nearest to the "BC25" text.
Solder a 220uF/10V SG or SH OsCon capacitor across C8; positive to the pad towards text "C9", negative to pad towards text "C8".
These measures take care of the most basic limitations of the sound quality of the Juli@ card."
___
I haven't tried any of this. just wanted to share.
I also take no credit for it, Thanks to marcello.
thanks to all the contributors here.
That's on old version mobo.
New version at 0.875V outputting 192k!
You should do it.
To replace the breakout cable should not be too hard. I guess I will start looking for a plug and simple enought to see which pins are used for digital out.
You are on the right track concerning getting rid of the connector and going straight to the board, though this could be slightly risky. I am not looking at the board at the moment and do not know how close together the solder pins are.
Thanks for the ideas.
Cordially,
Rick McInnis
hi,
i tried the direct soldering to the board for spdif: better than breakout and easy to solder.But my optical connection is still much better.
bye
alfred
Hi sonics
I'm very curious how you soldered in the BNC jack to the Juli@. I just acquired a Juli@ to replace an aging M-Audio Delta 1010... and the addition of BNC to the Delta was clearly an improvement (but limited to 96 KHz).
Is it possible to see a photo of your handiwork - that would be very helpful.
Thanks so much for your help.
Grant
But I do know that 192K sounds MUCH better than 96K on my system.
I have seen band-aid toslink receivers that convert to SPDIF but can't imagine that being an improvement.
Bye,
Rick McInnis
I took the 'rca out cable' from the breakout cable, cut off the rca connector , separated the ground shield wire from the positive center core wire (not easy because the shield wire is very small gage but it can be done) and soldered it to a bnc connector. Bnc's are better at the high frequencies like 192.
Thanks theob.
I will try it. I would also want to totally get rid of that breakout cable, it looks so cheap... I can't believe it doesn't impact on sound quality.
I know it's a digital signal made of zeros and ones, but I was raised in an "analogue" era where cables had an impact, or was it all just a perception !?! But I think that's a subject for another thread.
to be continued...
martin
With this setting, CPU voltage can be lowered - which is better. On old version GB mobo I have CPU voltage at 1.01875V (CPU-Z Vcc is 0.992V).
I set up my 'cics-pack' (cplay and cmp) with original bios settings from post for the new hw. I believe it was MIT set to auto and clock ratio to 9, fine control to 0.5, enable cpu host clock control, cpu host frequency to 200, memory multiplier to 2.
I get cpuz core voltage of .976 at idle, plus I'm running, src at 192, awe and let me give you more feedback on "nopae" it is simply magnificent. I was too harsh about highs in my initial post. This is the real deal in the highs.
What do I reset host freq to?
Set host frequency to to 170 - this is good for 192k @ SRC 145db SNR.
Midrange performance is exquisite! More bass energy and highs have more detail. I've never heard mids rendered with such perfection...
Yes very nice, a bit smoother or tube like in mids and highs. IYO in there a limit on how low you can go on clock with 24/192?
There is mention of editting noexecute=always off and that this works best when Bios Execute Disable Bit is disabled. I'm using the Gigabyte mobo and I believe this feature (Bios Execute Disable Bit is disabled) is not there. Is it still ok to try this as well as timeres and nodebug in the start up and recovery settings in control panel?Also I think somewhere between 200 and 170 clock setting in Bios might be optimum for me. Ok to try any value in between?
I made the clock switch to 180---perfect. Now I know how to trim my system after future changes if I should not like the balance.
Still would appreciate feedback on kernel revisions. Also I could only make some of the registry changes. Couldn't find New > Dword to disable balloons. Couldn't get MenuShowDelay, took care of prefetcher.In ntfs LAST UPDATE, ALREADY HAVE 'NTFSDISABLE8DOT3' SET TO 1. Is that same thing already set up?
I don't think I have Service pack 2. It must be xp pro initial release.
Quick feedback: much stronger bass, very very quick as Rick mentioned, more finely layered detail. Not sure about highs, not that I don't like them (quick rise time, just don't know if they will be fatiguing over time). All in all it's a big change, highs are very crystalizing, sharply delineated. Again time will be test of overall accepatability to me.Just listened to 1st classical piece: bigger soundstage, deeper, more air around instruments especially percussion. Strings are very sweet. I think I am going to like long term if this keeps up.
Dear cics,
I assume it does not matter where this goes within the line of text?
I will place it at the end.
If this is not correct, let me know.
I will see what happens.
Thanks,
Rick McInnis
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