6SJ7 in place of a 6SL7?

[boroman]

Wondering, if I put 6SJ7 in a place calling for 6SL7 (mainly, old ampeg amps), would that work with no harm to the amp? I have about 20+ 6SJ7 tubes laying around...

[Chuck H]

It doesn't work because the 6sj7 is a pentode and the 6sl7 is a dual triode. They are completely different tubes.

But if you have an amp that uses a 6sj7 tube you could test the ones you have for microphony and sell them. I've never dealt with them but from what I've read non microphonic 6sj7's are hard to come by.

[Delta362]

Having recently reworked an old Magnatone that had the 6SJ7 to a dual 6SL7, it was fun and not incredibly difficult given that my amp was hand wired and not PCB mounted. Not sure what the situation of your amp is, but if it's PCB socket, then it wouldn't work without major surgery. If it's wired, you could rewire it (and add a couple R and C) to make the dual triode work.

[Chuck H]

Having recently reworked an old Magnatone that had the 6SJ7 to a dual 6SL7, it was fun and not incredibly difficult given that my amp was hand wired and not PCB mounted. Not sure what the situation of your amp is, but if it's PCB socket, then it wouldn't work without major surgery. If it's wired, you could rewire it (and add a couple R and C) to make the dual triode work.

boroman wants to use a 6sj7 in place of the 6sl7. Not the other way around. I can't think of any way to make a pentode do the duty of two triodes since each triode will be doing a different function in the amp.

[Delta362]

Damn, I misread. Sorry about that. And you're right, taking two triodes down to a single pentode doesn't seem like it would work unless the two triodes were just basic gain stages in series. Then you might be able to replace the two with one, albeit with a much lower gain factor.

[boroman]

Thanks! So i I could think of vbuildimng a small amps with all those 6SJ7...