Thanks very much for your review, I agree its very much a 'toe tapper' 🙂
By the way, what value cap are you using as DC blocker before the trafo? While I calculated the minimum is around 100uF I found with 100uF/10V caps the ambience retrieval was rather poor - much better with 2700uF/6.3V.
By the way, what value cap are you using as DC blocker before the trafo? While I calculated the minimum is around 100uF I found with 100uF/10V caps the ambience retrieval was rather poor - much better with 2700uF/6.3V.
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the output caps of phidac has not been changed yet.
With the B1 buffer after the volume , is the change essential ? there is no lack of bass.
I will look for a 2700 uf cap to try.
BTW, the tape hiss in the recording is obvious . No hissing sound on pause in Foobar. is this normal?
With the B1 buffer after the volume , is the change essential ? there is no lack of bass.
I will look for a 2700 uf cap to try.
BTW, the tape hiss in the recording is obvious . No hissing sound on pause in Foobar. is this normal?
What caps are you using between B1 and the amp? Or does B1 have caps already built-in?
2700uF just happened to be a cap I had to hand, I suspect any value from 1000uF will work as well.
Does tape hiss change with recording? On some recordings (analog ones mostly) its more apparent.
2700uF just happened to be a cap I had to hand, I suspect any value from 1000uF will work as well.
Does tape hiss change with recording? On some recordings (analog ones mostly) its more apparent.
l have the green 10uf between B1 and amp
l hear the tape hiss in most of the albums that l do not hear when phidac is driving gainclone.
l will try different preamp and dac in front of the 8932 later
l hear the tape hiss in most of the albums that l do not hear when phidac is driving gainclone.
l will try different preamp and dac in front of the 8932 later
Paired Phidac with op amp based pre. DC off set about 70 mv. Put a 1000uf cap as dc blocker and bypass.
The tape hiss is no longer audible. Richard's suggestion is spot on.
Can l just remove the dc blocker at end of the pre?
The tape hiss is no longer audible. Richard's suggestion is spot on.
Can l just remove the dc blocker at end of the pre?
The pre is driving your pot? If so you definitely need a DC blocker before a pot or it'll go scratchy.
PhiDAC has 15uF in series with the outputs so no additional cap is needed. However I have found a SQ improvement from swapping out those on-board 15uF caps (C39,C51) and replacing them with off-board film caps of 4.7uF or higher. Or perhaps you've already done that which is why you mentioned a cap 'after phidac' ?
TNT,
The tape hiss is obviously in the recording because it will start and stop suddenly at the beginning and end of each track.
I think it has something to do with Phidac also because the tape hiss is not audible when i changed to 2 other diy dac.
the change in the value and type of output dc blocker cap in the pre amp does not fully solve the problem. it tends to be louder with lower value capacitor .
I intend to try another usb to i2s converter in front of the phidac soon.
TDA 8932 sounds very much like a tube amp but bass is much better .
The tape hiss is obviously in the recording because it will start and stop suddenly at the beginning and end of each track.
I think it has something to do with Phidac also because the tape hiss is not audible when i changed to 2 other diy dac.
the change in the value and type of output dc blocker cap in the pre amp does not fully solve the problem. it tends to be louder with lower value capacitor .
I intend to try another usb to i2s converter in front of the phidac soon.
TDA 8932 sounds very much like a tube amp but bass is much better .
BTw, the tape hiss is very soft and only audible if you listen for it . my speaker is 92 db /w sensitivity
Are you running your PhiDAC at 44.1kHz? At higher rates it will have a HF lift which will tend to accentuate tape hiss.
That's also my impression in that its easy to listen to, non-fatiguing, 3D - but it runs much, much cooler 🙂
Morning,
Richard is correct. The tape hiss is no longer audible after l change the Phidac to 44.1 kHz.
Thank you for the great support and great kits.
l will be on the look out for more of your future projects .
regards
kp93300
Richard is correct. The tape hiss is no longer audible after l change the Phidac to 44.1 kHz.
Thank you for the great support and great kits.
l will be on the look out for more of your future projects .
regards
kp93300
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I'm happy you resolved that issue. I am hoping you get a whole lot of pleasure listening to your music through the PhiDAC and monoAMPs.
R21, R10 and R9
Hi Richard,
I'am working on my amp again and finishing step 3 after having got the 3300µF elco and having done some other projects.
In your board stuffing guide there are the above mentioned resisitors not part of it. R21 is probably a zero Ohm resistor, if used, but when to use it?
And what to use for R9 and R10?
Pls. advice.
Best regards
Ernst
Hi Richard,
I'am working on my amp again and finishing step 3 after having got the 3300µF elco and having done some other projects.
In your board stuffing guide there are the above mentioned resisitors not part of it. R21 is probably a zero Ohm resistor, if used, but when to use it?
And what to use for R9 and R10?
Pls. advice.
Best regards
Ernst
Hi Ernst,
R21 is there for fixing hum problems, should they arise. Ideally the source component (e.g. DAC) and the amps will share the same 0V in which case R21 won't be needed at all. If its not possible to arrange a shared 0V connection then R21 can be used to reduce any hum that arises - start with 10ohm.
R9 and R10 are only required for TDA8932T ICs, as far as I'm aware we've never shipped any kits or amps with those. We use TDA8932BT which does not require R9,10 to be fitted.
R21 is there for fixing hum problems, should they arise. Ideally the source component (e.g. DAC) and the amps will share the same 0V in which case R21 won't be needed at all. If its not possible to arrange a shared 0V connection then R21 can be used to reduce any hum that arises - start with 10ohm.
R9 and R10 are only required for TDA8932T ICs, as far as I'm aware we've never shipped any kits or amps with those. We use TDA8932BT which does not require R9,10 to be fitted.