Where's the J2 schematic? Is it the ACA?
Per post #833, not yet published, amp is still in production.
Russellc
The 6moon review shows the SJEP120R125:
6moons audio reviews: FirstWatt J2
Papa has said the SEJP120R100 can also be used:
http://www.diyaudio.com/forums/pass...p170r550-better-building-amp.html#post2076321
This is also the part in the original JFET version of the F6.
Cheers,
Dennis
6moons audio reviews: FirstWatt J2
Papa has said the SEJP120R100 can also be used:
http://www.diyaudio.com/forums/pass...p170r550-better-building-amp.html#post2076321
This is also the part in the original JFET version of the F6.
Cheers,
Dennis
Per post #833, not yet published, amp is still in production.
Russellc
I know. I'm teasing 😉
I have both jfets.
There would be a miniscule advantage to grounding it. It is there to
trap the magnetism.
😎
Very prompt answer.....😀😀
Hope it comes not too late!
So I need FOUR of SEJP120R100 or SJEP120R125 per amp, correct?
Correct!
Also, don't forget the SJEP120R100A. More info about the "A" part here:
http://www.diyaudio.com/forums/pass-labs/222098-semisouth-goes-dodo-what-now-7.html#post3295925
http://www.diyaudio.com/forums/pass-labs/222098-semisouth-goes-dodo-what-now-7.html#post3295925
So I need FOUR of SEJP120R100 or SJEP120R125 per amp, correct?
You can build a perfectly fine version with something else, like the IRFP240,
on the current source. I have done it for test, and there were no complaints.
The output stage sound is dominated by the gain device on the negative
rail. The mu follower is quite neutral due to it's own local feedback.
I just used JFETs all around for consistency, and to avoid the internet troll
accusation "It's not really a JFET amp", which I saw in a posting once
regarding the F3. (Not on this site)
😎
I sent an email to semisouth, but havent heard anything back yet.
Russellc
You can build a perfectly fine version with something else, like the IRFP240,
on the current source. I have done it for test, and there were no complaints.
The output stage sound is dominated by the gain device on the negative
rail. The mu follower is quite neutral due to it's own local feedback.
I just used JFETs all around for consistency, and to avoid the internet troll
accusation "It's not really a JFET amp", which I saw in a posting once
regarding the F3. (Not on this site)
😎
Does it work the same for the F6?
I think I have still about 8-10 used SS R100 or R125. So when you use the IRFP240 as CCS you need only two SS for one amp.
I could look the next days with my curve tracer if I have some good pairs that could be used on the negative rail as Nelson mentioned as amplifying part.
They are all used, but working, so if anybody wants to make a fund for later release of the circuit....... PM me simply.
I could look the next days with my curve tracer if I have some good pairs that could be used on the negative rail as Nelson mentioned as amplifying part.
They are all used, but working, so if anybody wants to make a fund for later release of the circuit....... PM me simply.
Does it work the same for the F6?
F6 is push-pull, so both outputs are gain devices. I understand the J2 to be single ended like the Aleph, but with Mu follower instead of Aleph current source. But of course I haven't seen the circuit 🙁
OK, just sourced four SJEP120R125 from Diyaudio member, now to wait for release of Schematic!🙂
Russellc
Russellc
OK, just sourced four SJEP120R125 from Diyaudio member, now to wait for release of Schematic!🙂
Russellc
I am also joining you on the wait.
Just got notice mine are being prepared to ship. I realize it will be a while, but at least I've got the outputs. If nothing else, I believe these ere also used in the non mosfet version of F6.
I assume J2 uses standard power supply? If so I may as well score another Antek 5600VA 18 + 18 volt transformer, power supply caps and so forth, unless PS is still unknown. I will check 6Moons for review photos...
Russellc
I assume J2 uses standard power supply? If so I may as well score another Antek 5600VA 18 + 18 volt transformer, power supply caps and so forth, unless PS is still unknown. I will check 6Moons for review photos...
Russellc
I see no transformers, like M2 or F6, power supply seems standard. It does use 2SJ109 JFETs which will be a trick to find. Is this the one that a pair of 2SJ74BL can replicate? I may have a set of these on my Aleph J boards from 6L6's original group buy?
http://www.6moons.com/audioreviews/firstwatt10/j2_2.html
Russellc
http://www.6moons.com/audioreviews/firstwatt10/j2_2.html
Russellc
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