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In Reply to: RE: cMP - the open source high-end Memory Player posted by cics on December 30, 2007 at 04:42:01
Hi all
after a discussion with Mark (hfavandenpas) about to try the use of ferrite rings ( and caps) on a picoPSU, and his apparently good idea about positioning ferrite after the picopsu but not on the cable that feeds it, today I've performed this test.
Using a P24 extension cable I've isolated each positive cable for 12V, 5V and 3,3V so I've joined each cable of same voltage togheter with some ground cable. At the end I've had three ferrite rings, one for each voltage, put on the extension cable. No caps at this stage.
In brief: a disaster!
Sound quality was died, music lifeless, no more dynamic, no more transparency, a dull, muddy sound. Impossible to believe!
So I've removed extension cable and sound return gorgeous and transparent, full of dynamic. My usual sound quality, indeed.
My conclusion:
- ferrite after the picoPSU is harmful on sound quality
- P 24 feeding is very important for SQ, and picoPSU is a good solution if feeded by a linear PSU
- I can't understand why so disastrous effect. Could It be an alterate function of switching regulators of pico caused by interference of near ferrite magnetic field?
Follow Ups:
Hi Audiodan,I read your post and I’m also puzzled by the disastrous effect on Sound Quality you got in your setup.
In my setup only 3 ferrites on the P24 had no effect at all on SQ.
The effect in your setup is puzzling because most ferrites are only effective in aVHF region.
Depending on type of ferrite material used, most ferrites are effective in suppression noise in the 5 mHz too 500 Mhz region. See graphs.
Van on filtering, demping, ect
Van on filtering, demping, ect The effect in your setup is even more puzzling since you used only 3 ferrites (with no caps added).
So there should only be very little suppression of noise in the 5 mHz too 500 Mhz region.* Filtering the 12 Volt input of the Pico 160-XT.
As suggested by you, I made some progress in filtering the 12 V DC (from a Linear PSU) that powers the Pico.
Yesterday I already mentioned too Theo at the end of this post, the remarkable effect on filtering the 12V DC. power line too the Pico.
http://www.audioasylum.com/forums/pcaudio/messages/9/93301.html
I would never have expected that this would have improved sound quality remarkably.
The simple bench linear PSU I use to power the Pico, probably produces noise in the HF and VHF region.- 8 Ferrits on the 12V DC line. (combined with a ferrite/cap π-filter on the P24)
I placed 8 ferrits on the 12V dc power cable coming from a linear PSU too the Pico. This had no audible effect. (I haven’t experimented yet with adding caps too create a π-filter)- 2x 6 mH ferrite based chokes. (combined with a ferrite/cap π-filter on the P24)
2x 6 mH ferrite based chokes (with caps added) on the 12V DC power line to the Pico had profound effect on SQ. I would never have expected this. Thankx too your suggestion I tried.
But I’m not ready yet testing various ways of filtering the 12 V DC line too the Pico. So I will give a complete report in a few weeks on this.But thank you for the tip! Filtering the 12V DC line too the Pico combined with filtering the P24 with 7 flat ferrite clamps for ribbon cable with caps added, gave a really big (!) SQ improvement in my setup.
Thinking of the opposite effect you and I experienced through using Ferrite based filters.
It might also have some relation with your DAC being inside the computer on a soundcard. Your situation is extremely difficult and demands a superb quality of power supply. The performance of the DAC will suffer if not powered with superb high quality power.
May be my situation is less critical than yours, because I use an external DAC which is completely galvanicly isolated from the PC through use of a glass-toslink cable.Mark
fully optimized cMP2 PC -> ESI Juli@ -> Van den Hul Optocoupler MkII-> Lavry Black DA10 -> XLR Mogami Gold -> Klein & Hummel O300
Edits: 08/11/11
Hi Mark
I must report this new experience.
This morning I was working on the Essence of my "little cMP2", a portable unit that I've build to allow my friends to listen a cMP2 in their systems.
It was intriguin also for the PSU challenge, using the discrete Switching unit of Silverstone SUGO SG 5 coupled to a picoPSU (150 XT) through a run of Silmic (4000 mF) (also feeding the 12V of Xonar). Another run of Silmic was in the 5V line to the Xonar and 2000mF was put on the P4 line.
The "Sughetto" was build around an Intel 13 530 CPU (COOLER THERMALTAKE Ventirad Slim X3), a Gigabyte H55NUSB3 miniITX , a SSN Corsair for OS and one RAM Kingston 1GB 1333MHz DDR3 Non-ECC CL9 DIMM. It works well, it's a good Ambassador for cMP2 and, sincerely, it sounds really great-
On the table, this morning I've found the P24 extension with ferrites, the Sugo case was open and so, I put it on the P 24.
FANTASTIC RESULT!!!!
More air, more harmonic richesse, more silence in the background.
At this point I've added another ferrite on the P4 cable. Even better.
Now I must suppose that:
- This is a different mobo, with very different regulators
- In every line where I've put ferrites it exists a run of capacitors
- The phenomenon I've observed yesterday in the other my system is not due by picoPSU or Soundboard, in this case closer to ferrites then in other system
Here you are my nude "Sughetto"
The Essence side
The Ferrites and capacitors side
PS: here there are fans inside: impossible to avoid them.
After few hours of listening I've tried to remove extension and ferrites of P24.
It's better without, for me.
A lot more dynamic and slightly more transparent.
I'm perplexed. the effect is not surely the same I've noted in my principal( and linear) PC but without ferrites is better for me also in this one, period.
Daniele
Hey Danielle when I put ferrites on p4, p24 I got a darker sound (more like less bright) but more transparent to real upper mid musical cues. I heard more real info, got a deeper bigger soundstage.. I also got a bit more dynamics. Both Mark and I run 44 sr not 192 sr like I believe you use. That may be part of the reason for different perceptions. If you like your tonal balance before ferrites you may not like it with ferrites. My only perplexing reaction is that I don't get the huge sq pop that Mark gets at least not with my current mobo. Even though I dont get the big sq improvement I still prefer my system with ferites than without them.
Edits: 08/11/11
Hi theob
it's possible that upsampling I always use ( 24/192) reacts in this strange way to ferrites but It's the first time that I apply a reccomended upgrade with negative results, so this it seems strange to me, especially 'cause I can't find a valid explanation. I've found some positive effect putting ferrite on the line coming from linear PSU, bad one on the line "after" the picoPSU (the extension cable).
I must underline that my Sandy Bridge setting adds both dynamic and transparency to SQ so, maybe, ferrites action could be useless with this setting, also for the very different local regulators quality in the new mobo.
Anyway my "ferrite's story" stops here, but I'm curious about further developement, so I'll wait next Mark's report.
Thx to all
Daniele
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