How can I implement the D1-Stage with an Ultra-Analog-DAC (parasound 2000)? - Page 2 - diyAudio
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Old 5th January 2004, 11:32 AM   #11
Klaus is offline Klaus  Germany
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Quote:
Originally posted by promitheus
thatīs funny I was just looking at that before I read it here.

what did you use as output caps where Pass uses 220uF?

I use - like everywere in my Aleph4 mono block + Aleph P1.7 chain - 220uF Panasonic FC electrolytics bapassed with blue 10nF Vishay Roederstein MKP1837 (or older ERO KP1830). As written frequently before here I know no better cap. And they are so cheap...
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Old 5th January 2004, 11:59 AM   #12
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Nice work, Klaus. I just finished the as-symetrical D1-stage to test it first against the Output-Stage of my Sheldon DAC(passive I/V-conversion). When I did that, I will report back the results.

Why did you need 220uF output Cap ? I thought the cap-size is determined by the impedance it sees in the next stage, which should be 22k (in parallel with the impedance of the preamp. which is in my case 300K) in the case of the D1, right ?

Best Regards
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Old 5th January 2004, 12:12 PM   #13
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Hallo Blitz,

which DAC did you use it on?
I want to do the same thing but I was concerned about the output cap.
What cap did you use?
I also have an unbalance output.
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Old 5th January 2004, 12:45 PM   #14
Klaus is offline Klaus  Germany
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Quote:
Originally posted by Blitz
Nice work, Klaus. I just finished the as-symmetrical D1-stage to test it first against the Output-Stage of my Sheldon DAC(passive I/V-conversion). When I did that, I will report back the results.

Why did you need 220uF output Cap ? I thought the cap-size is determined by the impedance it sees in the next stage, which should be 22k (in parallel with the impedance of the preamp. which is in my case 300K) in the case of the D1, right ?

Best Regards
The output cap can not be to big, but to small. So I see no reason not to use 220uF like also the one and only is doing in the Aleph amps and the D1. For sure it could be decreased to some uF like many guys are doing. But maybe there are some effects due to "hardest possible coupling" of the cable output load to the active output stage by the very low ESR and inner impedance of a big cap.

Quote:
Originally posted by promitheus
Hallo Blitz,

which DAC did you use it on?
I want to do the same thing but I was concerned about the output cap.
What cap did you use?
I also have an unbalance output.
I checked the sound losses of coupling caps before I started to build up any Aleph stuff. To my mind these losses are less critical than negative sound effects by untweaked devices ore "basic" cables. The best tested Pass products show that even standard coupling caps can not be so bad... To much prejudices against coupling caps!
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Old 5th January 2004, 12:58 PM   #15
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well why use 220uF electrolytics when you can use 22-33uF MKP caps?
what you are suggesting is that someone could also use 1000uF electrolytic for better quality. That would be good for power supplies but not for in signal paths.
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Old 5th January 2004, 01:10 PM   #16
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The size of the output cap is 4.7uF - Mundorf Supreme. I think Klaus agrees with us on the superior quality of the supremes.

I seems that all the theory guys are on vacation to tell us which impedance the C really sees, so once I have it build in, I will use a measuremet CD to see wether we have losses in the bass with 4.7uF. - If 1uF would be suffiencient, I could even use a Supreme with silver/oil which I have here for testing...

The Sheldon-Dac uses the PCM63 as the original D1. Interesting enough Sheldon himself played around with all kind of filters for the HF-garbage and came to the conclusion, that listening to it without any filter is best. I can confirm that. Sofar this DAC has not been beaten by anything. MAybe Nelson or Klaus's output stage will do that job ?
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Old 5th January 2004, 01:17 PM   #17
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I think with a normal load of 47KOhm you only need 1-2uf.
If you use 10-22uF its more then enough even for loads down to 5KOhm.
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Old 5th January 2004, 01:41 PM   #18
Klaus is offline Klaus  Germany
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Quote:
Originally posted by Blitz
The size of the output cap is 4.7uF - Mundorf Supreme. I think Klaus agrees with us on the superior quality of the supremes.

I seems that all the theory guys are on vacation to tell us which impedance the C really sees, so once I have it build in, I will use a measuremet CD to see wether we have losses in the bass with 4.7uF. - If 1uF would be suffiencient, I could even use a Supreme with silver/oil which I have here for testing...

The Sheldon-Dac uses the PCM63 as the original D1. Interesting enough Sheldon himself played around with all kind of filters for the HF-garbage and came to the conclusion, that listening to it without any filter is best. I can confirm that. Sofar this DAC has not been beaten by anything. MAybe Nelson or Klaus's output stage will do that job ?

I use the Panasonic FC electrolytics + MKP bypass because they sound extremely open, dynamic and w/o any sonically problems for ca. 2€. The Supremes also sound superior (and much better also with 10nF MKP bypass - less sharp and more color), but they cost so much. Not to talk about this silver Supreme stuff... That is the only reason I do not use them.

Maybe the value of the cap regarding bass losses is not the main story, I think it has really something to do with how "hard" the cap couples the cable load and damp all parasitic effects. This is maybe given by the ESR value of the cap. Regarding this a 220uF electrolytic is very good. Bigger ones could get higher inductance and are not useful. But as Nelson and many other producers show 100 or 220uF seem to be suitable. Just test it and do not think to much about theory!

I can also just confirm that after throwing away the OPA filter chain a DAC plays like dynamic fire! Since my TDA1547 works almost without analog filter (just passive 6dB by a cap parallel to the I/U-resistor like also Nelson does) I hear really the music. It blows away almost everything. And I hear no artifacts from IM effects, so how relevant are really this HF distortions? I doubt they are.
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Old 5th January 2004, 02:37 PM   #19
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Klaus,

This sounds extremely promising, looking forward to see the schematic of the circuit and your sound description of course.

My Marantz CD16 with the TDA1547 inside is waiting for years now to prove that it can make music and I would use your outputstage 1:1.

Best Regards
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Old 6th January 2004, 06:42 AM   #20
Klaus is offline Klaus  Germany
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Quote:
Originally posted by Blitz
Klaus,

This sounds extremely promising, looking forward to see the schematic of the circuit and your sound description of course.

My Marantz CD16 with the TDA1547 inside is waiting for years now to prove that it can make music and I would use your outputstage 1:1.

Best Regards

I will come back to you and this forum asap...

The sound of the 2SK389 varies extremly with its bias current - I currently search for the best compromize. But the sound improovement still is unbeleavable!!!!! Simply like agin the change from a "normal" pre amp to the Aleph P1.7. And the CCSs seem to give a extreme stability of sound. And this bass...

tweaky regards

Klaus
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