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I do not give up to get my J2 clone nearer or on similar level than the original I have still for comparison reasons...... my newest try (a recommendation from the master himself) - omit the source resistor of the lower SemiSouth -loosen the feedback by choosing a value higher than 100k, I took for a try simply 150k you get of course more gain, about 6db more, so you may have a small hum problem and readjust some cables.... the sound is not the same like the original but on the same level........a bit more body I already liked with the MosFet inputstage......and still more engaged than the original. But I am afraid, I will stay the only one who tried this.... for exact and authentic people here comes the link to Nelsons statement starting with the words "Lord of the SIT sez:" http://www.diyaudio....tml#post2952893 and one link how to use two unmatched J109 in the J2 constellation.... http://www.diyaudio....tml#post3108123 good luck!

Yes, thank you for the reminder! The 9610 is set to 30mA in Pumpkin and I would set the the two J313 to 20mA, so only ten for each......I will hear....

I just remember that I changed two years ago after recommendation of ZM the 9610 in Pumpkin against the J313 and the difference was very clear, but at that time I preferred the "mosfet bloom" as Zen Mod calls it....the sound was clearly more detailed and I think it will come nearer to the 2J109....but I cannot try today, my wife occupies the room with the amp learning for an examination at university (Chinese)......so I hope I can soon communicate with the myriads of Pass cloners in China....

Danke!

Pa is of course in the sweet spot......me not....thanks Zen Mod

thanks Sipi for valuable hints.... and I take care of the panorama! :oke:and I will give the 2j313 a try instead of old 9610

yes 7,5mA per side.....and I confess "origigi"

Just for fun I changed today the one 2SJ109 BL in the BJ2 to a pair of closely matched 9610. (from diytech 0,01V), Zm will laugh, "change your lousy BJ2 back to an Aleph 3"My intention was to drive them with the 20mA the two 2SJ109 or four J74 get normally, and I was eager to hear if the much higher transconductance would do something to the sound.sound is (as often remarked) darker, a bit more punch in the lower bass, but much, much less detailed and airy than the J-Jfets.So back to one 2SJ109 per channel again.....Can anybody comment if going to 15mA with one 2SJ109 device would be to much, Euvl did even heatsinking the 2SJ109 in former times when they were still more in use....

I wish you could hear it!

update for all BJ2 fans and builders.... I occupied over 6 weeks with the sound of my BJ2 compared to an original FW J2........ it was a hard time...... I tried all.........................................................................................! I even ordered a pair of R125 because the FW J2 had them, from a guy at Miami, but, no the input was the place! To make it very short............................ to come near to 80% of the lovely sound of J2 original....... I had to take one pair of 2SJ109 in the input. ( I know it is a compromise) Every try to set in, even very closely matched quadrupels of J74, and not so closely matched two 2SJ109 in parallel, (I spend some money to buy them in Germany and I had to sent back some because they were sold defect.....) ................gave a more muddy sound. So if you want to experiment with your BJ2 and you still have a pair of good old 2SJ109 give it a try. After six weeks it is a happy day today!

Hi Aleksandar, very fine big Rifa caps! and what is the use of the small resistors near the CL60 thermistors? I am satiesfied that even you make the big holes in part one with many small holes with the drilling machine.....!

o.k. I bridged the 0R68 resistors and ....now in my system the sound gets even more precise but a bit too hard and less "panoramique"so I returned to the former constellation..incredible what o.34 Ohm changes.......!next tries come......

every suggestion welcomeI will try and hear....

O.K. thank you both for your explanations and hints.......! :)and I am afraid my cd-player is also pentode like so I have no chance......... :Pmaybe one point is important, the Mufollower is normally more push pull than single ended.....

But may be the SJEP120r100 is also triodish in the region of 1-2A .....So I ask myself why did Nelson develop his own SIT?

Hi Sipi,It is the SJEP R100 in a mullowerconstellation and I really would be very interested to try out the sound difference between the lower SS driven pentode like (at the moment) and triode like! Do you need data of the present feedback loop to change the characteristic?

Of course I meant SP300b and not 300B.......

Hi Sipi, I knew I could count on you when panoramique sound is in the air.......... Now we only need your Genius to change the feedbackloop to make a triode out of our pentode Semisouth to open another game....

I tried to paint my best.....and Zen Mod correct me If I am wrong with my assumptions, I feel strong today.......I do not want people trying something completely wrong....

Hi everybody, :respect:some news about BJ2....inspired by the SIT discussion and driving the SIT with a CCS i learned a bit more about Mu and CCS, really only a bit....but that does not avoid experimenting.....in the original BJ2 constellation the last recomendation for the resistors around the both Semisouth here in the thread for the source resistor of the upper Semisouth was 2x0,68Ohm parallel or 3x1Ohm. For the drain resistor of the lower SS 2x1 Ohm parallel and 2x0,47 Ohm for the source resistor of the lower SemiS.In this constellation both Semis contribute to the gain and wattage, so you can get 25W at 8 Ohm...Inspired by Nelsons comment on his SITs, that he wanted them speaking "more with one voice" I wanted to reduce the contribution of the upper Semisouth to a degree forming "nearly" a CCS.(I drive Lowther and Tone Tubby (96db) so I do not really need 25W, the half wattage could be sufficient......)I decided to change the arrangement of the drain and source resistors.......1. no source resistor any more for the lower Semisouth........2. but I took the "free" 2x0,47 Ohm and combined them with the 2x1 Ohm in series so I got about 0,75Ohm and put this combined resistors no more at the drain of the lower SemiS, but at the source of the upper SemiS!3. and of course the the former source resistors of the upper SemiS 2x0,68 Ohm (or 3x1 Ohm) got now the new drain resistor of the lower SemiS.result: less wattage but sounds lovely and more panoramique... :guitarplayer: :guitarplayer:of course it is now near to F2J, but you have the opto bias regulation and no cap at the output!really lovely.....if you have a Bj2 running (hello B300!) try it and report if I am wrong......

Hi tea-bag,It is incredible to hear your continuing story of pity with J2 ......You must hear this amp, it is lovely, especially in voices. Not totally exact, but the most charming boy I have heard.......I wrote already that BJ2 is a bit more dur and the other version is a bit more moll. It's only a matter of taste or mood.....And I prefer J2 clearly to F5.It seems to be a long time since Nelson gives free the circuit........

I want you to be a happy Master Camper.......!

Bubba is right, I also bought first the big green ones and was astonished how many different choices I had, but after some scratching of my head I realized the Master Zen Mod liked in Pumpkin the little small green ones .... :connie_nutzo: .So I bought a new batch and had no trouble.... It is always good to know the habits of ones master....

THX Zen Mod,Very good hint!

Hi tea-bag,This time it was j2 rev1, but Zens type of optocoupler....Ah forgot I managed to have no humming with the boards of Peter and I understand you that you like f2j really, it is also a very fine choice with Lowther.......