UGS adventures

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#1,105
roughly - what's the value of series resistor , that's input impedance per leg ; that's precise enough for most purposes

inputs are inverting , ref to correspondent outputs ; so they're acting as virtual gnd (looking from preceding stage) and there lies the reason for that simplicity

you meant on that ?
 
#1,107
sort of

whatever - going much above 10K for pot is way to introduce cable irregularities in game

almost any decent source nowadays is having max output impedance in range of max 600R , so capable to drive 10K pot

if not , then quality of source in question isn't on par with UGS
 
#1,108
samoloko said:
when using unbalanced mode UGS v3 with unbalanced In+ to unbalanced Out+ Is It correct to ground In- and Out-
at first I was using UGS v3 with not grounded In- and Out- then I grounded In- and Out- and got more gain but for me the sound become somehow unplesant
are R In and R FB and R G the most critical resistors which got to be of highest quality

http://www.diyaudio.com/forums/pass-labs/86300-ugs-adventures-5.html#post1008158
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thanks samoloko, I know I saw that long post of Cheffs somewhere. It explains, well, almost everything. 🙂
 
#1,109
Maousse said:
I use my Cheff's UGS All Inclusive in unbal/unbal config for now.
My amp has 29dB gain, that makes 1.2V sensibility.

Cheff's UGS gain is enough for my configuration, I guess it could be OK for you too.

About PCB's, the Gerber Files are on the site liked on my previous post. But cost can be high for just one set. I have a spare full set if you need (I keep it for my old days ^^)
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Maousse, I would like to buy that spare set of PCBs. Please let me know and PM me. Looked at the gerbers, still cannot find UGS module and the UGS PS (+-24V dual) gerbers. What file names I should be looking for? The thing is I would like to re-design the PS PCB so that it can fit a non-EU transformer like the one you see in my PS picture. Also it would be nice to re-design the pin layout of the UGS module so that we could fit single JFETs instead of those hard to find duals. What do you think?
 
#1,113
Tonight I did my first audio test with bare bone UGS modules. The setup: iPhone 5 as a digital source 192K, 24 bit resolution, D/A -> UGS unbalanced, Out(-) was left open meaning the gain was ~3dB -> a stock Hafler DH220 power amp -> Goodmans Axiom enclosures with Altec 12" woofers. The sound was astonishing, crisp and exceptionally detailed. I only played good old pop from the 70s and 80s digitally enhanced. For comparison I also have a PassLabs X2.5 as well as Aleph P and the UGS is right there side by side with those 2 exceptional pre-amps. I also did a audio tone test using Sound Tone app, 20Hz - 16KHz (I cannot hear tones above 16K with a normal listening sound pressure). Anyway the UGS blew me away and I cannot wait to build the rest of this astonishing pre-amp with input selector, volume control and the remote. stay tuned....
 
#1,115
rade95 said:
Tonight I did my first audio test with bare bone UGS modules. The setup: iPhone 5 as a digital source 192K, 24 bit resolution, D/A -> UGS unbalanced, Out(-) was left open meaning the gain was ~3dB -> a stock Hafler DH220 power amp -> Goodmans Axiom enclosures with Altec 12" woofers. The sound was astonishing, crisp and exceptionally detailed. I only played good old pop from the 70s and 80s digitally enhanced. For comparison I also have a PassLabs X2.5 as well as Aleph P and the UGS is right there side by side with those 2 exceptional pre-amps. I also did a audio tone test using Sound Tone app, 20Hz - 16KHz (I cannot hear tones above 16K with a normal listening sound pressure). Anyway the UGS blew me away and I cannot wait to build the rest of this astonishing pre-amp with input selector, volume control and the remote. stay tuned....
Click to expand...

what Idss are your jfets In UGS and someone please recommend best values
 
#1,116
samoloko said:
what Idss are your jfets In UGS and someone please recommend best values
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The UGS modules I have were already assembled some time ago by another diy-er, who lost interest, so they use good old dual K389/J109BLs. I feel lucky 🙂 Now I want to assemble another pair of modules using discrete JFETs, but this will take some time since I haven't got the PCBs yet. What do you have?
 
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