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Old 30th March 2013, 03:05 PM   #301
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Quote:
Originally Posted by Corvus5 View Post
I minimized semi-HF jitter (+/-50Hz) later too. The Vcom caps are on the board, to the left of the DAC. The stock is AFAIR Nichicon Fine Gold 47uF 25V. The stock measure is not available. It depends on too many things.
If you don't have measurements of stock (Nichicon Fine Gold 47uF 25V), are you saying that for the comparison graphs you posted, even worse-measured Vcom caps you installed SOUND better than stock?
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Old 30th March 2013, 04:24 PM   #302
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Quote:
Originally Posted by hollowman View Post
If you don't have measurements of stock (Nichicon Fine Gold 47uF 25V), are you saying that for the comparison graphs you posted, even worse-measured Vcom caps you installed SOUND better than stock?
No, I'm not saying that
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Old 1st April 2013, 02:48 PM   #303
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How can you describe in a few words difference in sound when you changed capacitors at Vcom position?
What kind of capacitors do you have at analog supply and sigital supply raw, on pcm1792. What kind of regulator did you used?
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Old 2nd April 2013, 09:17 PM   #304
Corvus5 is offline Corvus5  Poland
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Sure, I can, tomorrow. I described this already. Now I used stack of 4 ultra low ESR ceramic smd caps 2mm long for both 7805 output filtering. There's a difference when compared to using one. So powerful bass as so much space for more reverberation to be restored later. I've never fought my current drivers can provide such a strong bass.
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Old 3rd April 2013, 10:13 AM   #305
Corvus5 is offline Corvus5  Poland
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Different Vcom caps. One is 10uF ceramic ultra low ESR with AFAIR ~15mohm at 100kHz. The other is tantalum 220uF with ESR~200-300mohm at 100kHz. Forgot which channel is for which cap, but you may notice the difference. The sound distance is different: the left is farther, the right is closer and little louder. Which has lower audible distortion is hard to tell in the current configuration. The left may be smoothed and distanced by distortion, or the right is sharper and closer due to distortion ;-)
Attached Images
File Type: png H13 - Noise.png (23.0 KB, 152 views)
File Type: png H13 - THD 1.png (21.2 KB, 149 views)
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File Type: png H13 - THD 4.png (21.1 KB, 141 views)
File Type: png H13 - THD 5.png (27.4 KB, 26 views)
File Type: png H13 - IMD 1.png (27.0 KB, 26 views)
File Type: png H13 - IMD 2.png (29.0 KB, 25 views)
File Type: png H13 - IMD 3.png (31.8 KB, 28 views)
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Old 3rd April 2013, 11:25 PM   #306
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Default Armchair DIY

Quote:
Originally Posted by Corvus5 View Post
Different Vcom caps. Forgot which channel is for which cap, but you may notice the difference.
Realize that the graphical asymmetry and charac channel diffs. may be due to the fact that you're using two diff. caps for the L and R Vcom pins (i.e., interactivity or synergistics) . Use of either cap you installed on both sides -- i.e., restoring symmetry -- may result in curves that look like neither in your current graphs.
Anyway, glad you're brave enough to experiment with that card so frequently ... many of us will wait until you've figured things out a bit better. We prefer armchair DIY ... speaking of which, why not improve the regulator ckt for the TCXO? That takes very few extra components, and its "footprint" is minor. E.g., Some have noted that for fixed-voltage regs., 33uF parallel with 10uF+0.47R on its OUT (the 10uF should be high. qual. cap like Pana FM). Avoid higher cap values at OUT.
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Old 4th April 2013, 07:53 AM   #307
Corvus5 is offline Corvus5  Poland
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Quote:
Originally Posted by hollowman View Post
Realize that the graphical asymmetry and charac channel diffs. may be due to the fact that you're using two diff. caps for the L and R Vcom pins (i.e., interactivity or synergistics) . Use of either cap you installed on both sides -- i.e., restoring symmetry -- may result in curves that look like neither in your current graphs.
Anyway, glad you're brave enough to experiment with that card so frequently ... many of us will wait until you've figured things out a bit better. We prefer armchair DIY ... speaking of which, why not improve the regulator ckt for the TCXO? That takes very few extra components, and its "footprint" is minor. E.g., Some have noted that for fixed-voltage regs., 33uF parallel with 10uF+0.47R on its OUT (the 10uF should be high. qual. cap like Pana FM). Avoid higher cap values at OUT.
That's what I said: I used different caps with purpose. From my experience your setting wouldn't work properly: what's the need of 10uF when using 33uF? It could be better with your (33uF + 0.47R) // 100nF. Still bypassing caps sounds bad to me, even decoupling. This causes a lot of loops which is bad for audio performance. Now I use no decoupling and no R/L element in the path as much as I could after final regulators. I only allow one cap after regulator. For analog 7805 it's 4xTDK C2012 10uF 10V, for 7812 and -12V it's a series of 2 TDK C2012 10uF 10V. The 7805 for clock also has 4 of these C2012 caps on the output.

There's no need to upgrade clock when other stages are not corrected. I don't like how the Vanguard TCXO makes the power line so noisy. Soon I'll be comparing this card with the Xonar Essence One and some <$2.000 amps. Hope the ST won't be beaten fast
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Old 4th April 2013, 08:05 PM   #308
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Corvus5 said " Still bypassing caps sounds bad to me, even decoupling. This causes a lot of loops which is bad for audio performance. "
So, bypass/decouple as close to component as possible. Sorry there are no easy solutions. Not sure I agree with your scattershot approach (see my comments earlier in this thread on that issue) = A lot of blind, hard work. You may want to breadboard just the clock -- use a 'scope to "tune".
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Old 4th April 2013, 09:20 PM   #309
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IMD 60Hz + 7kHz. Looks nice and sound very good. Still the same different Vcom caps like in previous posts.
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Old 5th April 2013, 05:46 PM   #310
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How i can disable digital filter in PCM1792 chip which is used in this audio card ?
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