You need at least 7 mA (2x 3,5mA) (6mA should work though). Running the JFets at Idss is plenty. It wont hurt if you take some with higher Idss, but I dont think that you can expect any improvement ...
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based on schematic posted here http://www.diyaudio.com/forums/pass-labs/86300-ugs-adventures-5.html#post1008158 which resistors are most critical to sound quality and got to be of high quality
I like to use DALE RN55 everywhere, including the commuted ladder attenuator.
So I didn't questionned myself about that.
It seems that you are not satisfied with the resulting sound.
You may be have some other problem that have to be solved first.
Using standard metal film resistors, the sound was already astounding (compared to live sound of classic music), so I permit myself to ask.
Can you post some pictures of your preamp version please (in particuliar the Cheff's UGS modules) ?
So I didn't questionned myself about that.
It seems that you are not satisfied with the resulting sound.
You may be have some other problem that have to be solved first.
Using standard metal film resistors, the sound was already astounding (compared to live sound of classic music), so I permit myself to ask.
Can you post some pictures of your preamp version please (in particuliar the Cheff's UGS modules) ?
Hi Ivan,
Yes, why not ? higher voltage (no use) and half the current tranfer (still OK)
In Pass Labs X350.5 amp, there are 2 "UGS 5" modules, got 2 pots each channel, signed as "ABS" and "DIFF". So I guess I can adjust these 2 offsets the same way?
"(1) Short inputs to ground", I am using balanced input, does this mean I short 3 pins of XLR connector?
Thank you.
"(1) Short inputs to ground", I am using balanced input, does this mean I short 3 pins of XLR connector?
Thank you.
Hello to all.
I recently acquired a set of boards (13 pieces) of this mighty preamp. I gathered most of the documents but I noticed the BOM for the input selector/ladder attenuator is not available. I tried all the links posted on this thread but all of them are DEAD, anyone with the documents kindly send it to me please. Thanking you in advance.
Cheers,
Junie
I recently acquired a set of boards (13 pieces) of this mighty preamp. I gathered most of the documents but I noticed the BOM for the input selector/ladder attenuator is not available. I tried all the links posted on this thread but all of them are DEAD, anyone with the documents kindly send it to me please. Thanking you in advance.
Cheers,
Junie
Junie raises an interesting question. Why not a second buy of PCBs. Perhaps not all 13, but is there interest for the preamp modules? Or, perhaps people are interested in all the PCBs?
That might be a good idea, this is a fantastic preamp....had mine for ages and it still makes my day
...it's perfectly doable with the new LSKs or matched 2SK170 and 2SJ74's.
There are plenty of options but the one most of us used was the one from GB since that gave us a great price: OMRON G6S-2G-Y
24VDC