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Hotrodding the X-Fi: A Layman's Guide (No 56k) - Page 82

post #1216 of 2194
Quote:
Originally Posted by bichi View Post
metalized-film? - power bypass or coupling? (thought you are using direct-coupling, right?)

about to measure DC component on coupling caps, both Line-In (to Wolfson WM8775 ADC) and Line-Out (from Cirrus CS4382 DAC to op amp(s) differential input)

Back in a bit, with results....
Power bypass for the opamp power supply. Yes metalyzed film 12uf caps & yes DACs direct coupled
post #1217 of 2194
Sound like there is enough capacitance in the by passes to be able to rely strickly on the bypasses. sound quite full compared to the the smaller 3.3uf caps but retains the detail of the smaller bypasses.

This is what I figured would happen with the larger bypasses
post #1218 of 2194
Quote:
Originally Posted by germanium View Post
Sound like there is enough capacitance in the by passes to be able to rely strickly on the bypasses. sound quite full compared to the the smaller 3.3uf caps but retains the detail of the smaller bypasses.
This is what I figured would happen with the larger bypasses
Interesting.... replaced electrolytics with tantalums as bypass:
- 22uf on analog and digital power inputs, on Wolfson DAC.
- 6.8uf to 47uf on Cirrus ADC power inputs, depending on function.
- 10uf on Op amp -5vdc section.

Wonder if we are getting the same "sonic" impact/improvements?

DC Bias on Line-Out coupling caps:
- 2.15vdc @ 827ua (Cirrus CS4382 DAC AOUTA+/A- and AOUTB+/- to op amps)
- (corrected...)

DC Bias on Line-In coupling caps:
- 2.44vdc (Line-In to Wolfson ADC, AIN2L/R, pins #26, #27)
- odd thing is Creative installed NP 4.7uf G-Luxon caps - (replaced with Panasonic S, 4.7uf @ 25vdc, polarity correct)

EDIT: decimal error
post #1219 of 2194
Quote:
Originally Posted by bichi View Post
Interesting.... replaced electrolytics with tantalums as bypass:
- 22uf on analog and digital power inputs, on Wolfson DAC.
- 6.8uf to 47uf on Cirrus ADC power inputs, depending on function.
- 10uf on Op amp -5vdc section.

Wonder if we are getting the same "sonic" impact/improvements?

DC Bias on Line-Out coupling caps: 2.15vdc @ 827ma (Cirrus CS4382 AOUTA+/A- and AOUTB+/- to op amps)
- 827ma (1.88watts!) seems very high, so no shorting bypass caps for me, at the moment, until I figure out the circuit
D.C. cancels when both + & - caps are bypassed at the output of the opamps. The amperage you quote sounds like you shorted the output of the DACs to ground which is very bad. you have to be carefull when testing. But then again it seems that you would know that.
post #1220 of 2194
Quote:
Originally Posted by germanium View Post
D.C. cancels when both + & - caps are bypassed at the output of the opamps. The amperage you quote sounds like you shorted the output of the DACs to ground which is very bad. you have to be carefull when testing. But then again it seems that you would know that.
WHAT? - yer a toad! short to ground? - LMAO!
- made a stupid decimal error
- set 2ma range setting and seeing .827 in display....
- need some food, LOL!
post #1221 of 2194
Quote:
Originally Posted by bichi View Post
WHAT? - yer a toad! short to ground? - LMAO!
croak, croak, rivit, rivit, croak,croak
post #1222 of 2194
So thats microamps then. Thats a lot better
post #1223 of 2194
Quote:
Originally Posted by germanium View Post
Enabled bit matched recording in XP, New results

noise -96.6db
Dynamics 96.7db
THD .0009%
IMD .0042
IMD swept .0043
crosstalk -96.9db

Will retest in Windows Vista with bit matched recording enabled
woo, very good result!!

Someone told me using the latest beta driver
http://file9.mydrivers.com/sound/cre...a_20070711.zip

the stock card can also reach very good result as below: (don't know whether is under XP or Vista32 or Vista64, but the driver is for all platforms)

Frequency response (from 40 Hz to 15 kHz), dB +0.02, -0.07 Excellent
Noise level, dB (A) -96.1 Excellent
Dynamic range, dB (A) 96.3 Excellent
THD, % 0.0005 Excellent
THD + Noise, dB (A) -90.1 Very good
IMD + Noise, % 0.0043 Excellent
Stereo crosstalk, dB -95.7 Excellent
IMD at 10 kHz, % 0.0044 Excellent
General performance Excellent


details below:
http://bbs.bacao.net/sound/xfi_new.htm


I'm using Vista always, I don't have XP installed, so all the results from me are under Vista 32bit. I think the result from XP is better than from Vista, right? Is there any listening different?

Germanium, which driver are you using under Vista? You can try the latest beta driver since I was told "results are better and sound quality is better too"!
post #1224 of 2194
Quote:
Originally Posted by germanium View Post
Sound like there is enough capacitance in the by passes to be able to rely strickly on the bypasses. sound quite full compared to the the smaller 3.3uf caps but retains the detail of the smaller bypasses.

This is what I figured would happen with the larger bypasses

That's wonderful result! Do you think bypass the 3 with 18uf or 22uf is even good for fullness and distortion?

Can you indicate which are ADC power supply caps? From your aboves, I think bypass these caps with your suggested capacitance film caps will improve too.
post #1225 of 2194
Quote:
Originally Posted by ter1 View Post
woo, very good result!!

Someone told me using the latest beta driver
http://file9.mydrivers.com/sound/cre...a_20070711.zip

the stock card can also reach very good result as below: (don't know whether is under XP or Vista32 or Vista64, but the driver is for all platforms)

Frequency response (from 40 Hz to 15 kHz), dB +0.02, -0.07 Excellent
Noise level, dB (A) -96.1 Excellent
Dynamic range, dB (A) 96.3 Excellent
THD, % 0.0005 Excellent
THD + Noise, dB (A) -90.1 Very good
IMD + Noise, % 0.0043 Excellent
Stereo crosstalk, dB -95.7 Excellent
IMD at 10 kHz, % 0.0044 Excellent
General performance Excellent


details below:
http://bbs.bacao.net/sound/xfi_new.htm


I'm using Vista always, I don't have XP installed, so all the results from me are under Vista 32bit. I think the result from XP is better than from Vista, right? Is there any listening different?

Germanium, which driver are you using under Vista? You can try the latest beta driver since I was told "results are better and sound quality is better too"!
My THD is higher mainly due to the D.C. couplind as there is some D.C. offset but all other distotion on my card seems to measure better on my card. The THD increase is solely 2nd harmonic & not an issue really as that is the most benign THD componant. Studies have shown that the 2nd harmonic can be as high as 5% before it is audibe as it is easily masked by the nearby much louder fundemental. I'm not worried about the THD numbers really as it is no consequence to the quality of the output.

I'm using the driver that came on the CD for XP & 2.13.0012 for Windows Vista X-64 Ultimate.
post #1226 of 2194
Quote:
Originally Posted by germanium View Post
My THD is higher mainly due to the D.C. couplind as there is some D.C. offset but all other distotion on my card seems to measure better on my card. The THD increase is solely 2nd harmonic & not an issue really as that is the most benign THD componant. Studies have shown that the 2nd harmonic can be as high as 5% before it is audibe as it is easily masked by the nearby much louder fundemental. I'm not worried about the THD numbers really as it is no consequence to the quality of the output.

I'm using the driver that came on the CD for XP & 2.13.0012 for Windows Vista X-64 Ultimate.
Thanks! Any differences of listening experience between your Vista64 and XP?

I definitely suggest you use the latest driver. May there by huge improvement!
post #1227 of 2194
Quote:
Originally Posted by ter1 View Post
That's wonderful result! Do you think bypass the 3 with 18uf or 22uf is even good for fullness and distortion?

Can you indicate which are ADC power supply caps? From your aboves, I think bypass these caps with your suggested capacitance film caps will improve too.
You can get away with replacing the electrolytic altogether At those sizes I think.The ESR of metalyzed films are lower than electrolytics at 10% the elctrolytics size.

Not sure what the power supply caps near the ADC are for. Whether for DAC or ADC but wouldnt hurt to bypass them I believe.

The 4 cap at the edge of the board near the ADC need to stay electrolytic of some form as they need to be large to reduce distortion in the ADC. You can increase them to 1000uf according to the ADC manufacturer as that would lower distortion at the low end.
post #1228 of 2194
Quote:
Originally Posted by ter1 View Post
Thanks! Any differences of listening experience between your Vista64 and XP?

I definitely suggest you use the latest driver. May there by huge improvement!
haven't done much listening on XP lately but given the numbers XP might actually be better but only if certain criteria are met.

1. Bit matched playback is checked
2.card sample rate changed to 44.1KHz from 48KHz which can only be done on xp in the Audio Creation Mode when listening to CDs. 48 or 96KHz when listening to or watching DVDs
post #1229 of 2194
Going to get something to eat be back ibn couple of hours. Bye for now.
post #1230 of 2194
Do you guys think the Prelude or XtremeMusic with LM4562 op amps and Black Gate capacitor would be able to drive the HD650's OK or would I see major benefits using an external amp?
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