What To Do With Those 2SJ28's

[Soundhappy]

..I believe that second trimmer is hidden behind the capacitor..

Yes high probability

 

[rolandong]

Aleph J like output with optocoupler bias with paraller SJ28 vfet and iron voltage gain😕

 

[woofertester]

My guess is that the TO3 MOSFETs are the same as in the Aleph30, the Harris IRF244.

 

[rideht]

Could it be single-ended balanced?

 

[Nelson Pass]

No.

I think you will be amused when it is unveiled.

 

[nicoch58]

😀😀

 

[Soundhappy]

..I think you will be amused when it is unveiled.

Unveiled one possible ? 😀
Twice amused

 

[dantwomey]

No.

I think you will be amused when it is unveiled.

😀

 

[WBS]

Unveiling soon on a thread near you!!!

 

[Soundhappy]

😀 tic tac tic tac..
Amplifier circuit on the prototype PCB look like an easy build

 

[Nelson Pass]

But not an easy design.

😉

 

[nicoch58]

We know Nelson we are very lucky ....

 

[Rodeodave]

The "mystery transistor" has a really strange package. Low profile, sharp bend, wide brim, kinda pitted surface finish.

Maybe a KP926B?

The unotainums, or at least the leftmost one, may very well be IRF240.

 

[Nelson Pass]

Hint: They are from my NOS inventory.

 

[Soundhappy]

Let's try IRF130 or IRF9130 ? MJ 110**?

 

[codyt]

Hint: They are from my NOS inventory.

Yamaha 2Sk76!😀

 

[vdi_nenna]

It's the new SITs used for radar. 😉

 

[nicoch58]

 

[Soundhappy]

Hint: They are from my NOS inventory.

Can be NOS from inventory, but was never used in any amplifier

 

[Zen Mod]

completely unknown, never used part