Dear all,
You might laught at me to ask such question :
I have downloaded the X2_Rev 0,1,2 &3.
Where I can find the full detail schemtic of "UGS3,4" ?
Best Rgards !
Thomas
You might laught at me to ask such question :
I have downloaded the X2_Rev 0,1,2 &3.
Where I can find the full detail schemtic of "UGS3,4" ?
Best Rgards !
Thomas
Nelson still uses the UGS modules as parts in his current product line, and thus will not release it's details.
To answser another of your questions to me on the volume control, for the X2's you simply need a normal stereo attenuator. Since my CC-CCS-X-BZLS does all SE-Bal & Bal-Se conversion and provide gain in a single stage, I had to resort to a balanced stereo attenuator. I sourced mine from Parts Connexion. It is a 4 deck, single pole per deck, 23 position switch by Electroswitch, with 96 Holco resistors.
Cheers, Terry
To answser another of your questions to me on the volume control, for the X2's you simply need a normal stereo attenuator. Since my CC-CCS-X-BZLS does all SE-Bal & Bal-Se conversion and provide gain in a single stage, I had to resort to a balanced stereo attenuator. I sourced mine from Parts Connexion. It is a 4 deck, single pole per deck, 23 position switch by Electroswitch, with 96 Holco resistors.
Cheers, Terry
It seems to me that I recently received some email from
somebody who reverse-engineered a UGS and gave an
accurate enough description, asking for permission to
post it, which he didn't need but which I gave. I haven't
seen it here, though.
😎
somebody who reverse-engineered a UGS and gave an
accurate enough description, asking for permission to
post it, which he didn't need but which I gave. I haven't
seen it here, though.
😎
Yes please, I too would be interested in this.
Once upon a time I thought I had the UGS figured out and was going try building a proto. NP has very graciously dumped lots of breadcrumbs on this particular trail. From info he had given plus photos on the Pass Labs site it appeared that the UGS was a JFET/MOSFET implementation of Fig. 2 of patent 5,376,899. However, one post by on 11/20/03 put the kibosh on that.
A member (petter) writes:
"Many of Pass' recent designs that have been in the public domain use folded cascode. All X series units by definition need to use it (with the possible exception of the XA range). If you think about it, how else can you make a fully DC coupled single gain stage where the input DC level is the same as the output DC level?"
NP responds:
"Actually not true. Folded cascode is not essential, and appears in
in two commercial Pass Designs, the X600 and X1000 (which have
exactly the same circuit board. The lesser X designs are seen to
use ordinary cascoding on the front end.
In the XA designs we have no cascoding, and that would be consistent with the Aleph circuitry. That does not mean it
might not eventually make an appearance somewhere, folded
or otherwise."
At this point I find it difficult to figure out a number of elements, for instance the two pots. So yes, whoever you are, please post your ideas.
GL
Once upon a time I thought I had the UGS figured out and was going try building a proto. NP has very graciously dumped lots of breadcrumbs on this particular trail. From info he had given plus photos on the Pass Labs site it appeared that the UGS was a JFET/MOSFET implementation of Fig. 2 of patent 5,376,899. However, one post by on 11/20/03 put the kibosh on that.
A member (petter) writes:
"Many of Pass' recent designs that have been in the public domain use folded cascode. All X series units by definition need to use it (with the possible exception of the XA range). If you think about it, how else can you make a fully DC coupled single gain stage where the input DC level is the same as the output DC level?"
NP responds:
"Actually not true. Folded cascode is not essential, and appears in
in two commercial Pass Designs, the X600 and X1000 (which have
exactly the same circuit board. The lesser X designs are seen to
use ordinary cascoding on the front end.
In the XA designs we have no cascoding, and that would be consistent with the Aleph circuitry. That does not mean it
might not eventually make an appearance somewhere, folded
or otherwise."
At this point I find it difficult to figure out a number of elements, for instance the two pots. So yes, whoever you are, please post your ideas.
GL
vit said:
At the risk of creating trouble, I looked it up and it was....
***** ACAUDIO *****
Although at the time he still had some work to do on it.
be patient 😉
I had an idea and drawn this circuit. It is based a little on answers and publications from Mr.Pass and publications from Mr.Borbely in Audio Electronics (The new frontiers-> Basis knowledge to JFETs) .
I mailed this to Mr.Pass with ask for publishing-permission (Thank you Mr.Pass).
He answered Passlabs use only a single set of secondary mosfets, so I have simplified this. External components are not drawn. Actually schematic coming soon. (I play at present a little with the values)
Please excuse my very poor english.
Best wishes
Adam
Attachments
Did you draw the schematic this way in order to explicitely show an "X"? 😀
PS: your english is ganz gut
PS: your english is ganz gut
Bricolo said:
I like "X" 😀
In the figure of feedback (next update) is this so simply to draw.
/Adam
Interesting...
...as I also had Pass (Zen V5 for the second stage and the Susy patent for input) and some Borbely articles in mind for this....
NB-Don't rely on the values, and I think that some compensation caps would be needed. It's just the topology I want to show...don't know if it will work, still buying (=looking for
) the components...
Later, Tino
...as I also had Pass (Zen V5 for the second stage and the Susy patent for input) and some Borbely articles in mind for this....
NB-Don't rely on the values, and I think that some compensation caps would be needed. It's just the topology I want to show...don't know if it will work, still buying (=looking for
) the components...Later, Tino
Attachments
As I saw Acaudio's Board.....
.....I thought this would be the natural evolution of the circuit above 😀
But now you overtook me in posting the schematic, and yours seems to be quite more refined...
Am I wrong or can I see some John Curl elements in the input stage?
Well, I attach my proposal of the balanced thing....
Ciao, Tino
.....I thought this would be the natural evolution of the circuit above 😀
But now you overtook me in posting the schematic, and yours seems to be quite more refined...
Am I wrong or can I see some John Curl elements in the input stage?
Well, I attach my proposal of the balanced thing....
Ciao, Tino
Attachments
Re: Interesting...
It looks very similar,I think, it will work, my works already.
adam
zinsula said:...as I also had Pass (Zen V5 for the second stage and the Susy patent for input) and some Borbely articles in mind for this....
NB-Don't rely on the values, and I think that some compensation caps would be needed. It's just the topology I want to show...don't know if it will work, still buying (=looking for
Later, Tino
It looks very similar,I think, it will work, my works already.
adam
Outstanding work gentlemen. Thank you for posting. This looks like it could turn into a great thread.
ACAUDIO: It looks like your schematic has twice as many MOSFETS as the PCB. Is this what you meant by "Passlabs use only a single set of secondary mosfets"?
GL
ACAUDIO: It looks like your schematic has twice as many MOSFETS as the PCB. Is this what you meant by "Passlabs use only a single set of secondary mosfets"?
GL
Shouldn't the JFETs be cascoded - I thought I read this in a post from Nelson Pass (would also similar to the Borbely design) ?
That would be great.gl said:
I was "dreaming" of stuffing the non balanced circuit on a very compact PCB without input and feedback resistors, just as an op amp replacement.... 😎
But this balanced thing is also quite interesting. Nelson mentioned not too long ago, that the susy principle will work best with low feedback ratios. What is low? < 20dB, or even less?
I believe that my circuits will have at least 60dB open loop gain (don't know yet), so for 10 dB gain we have a loop gain of 50 dB. Too much?
Well, I'll have to go sleep now...
MRupp said:
It depends, with source degeneration, not too much gain in the first stage and not too high input impedance, I don't think that it is an issue. But only listening will tell.....
Oh, yes, if we would like higher rails, then cascoding is a must. J-fets cannot take high voltage around them.
But now, definitly.....Buona Notte.
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