Amplifier based on 2N3055

That reminds me of the early '80's when I decided to build a 'lousy' stereo transistor zero bias 741 opamp input ceramic capacitor diode switched class H amplifier with a quasi-complementary configuration output with 2n3055s using mostly parts I had laying around. I don't even recall now if I used any heat sinks at all - I figured I could slide since the supply rails would only support about 25W/channel.

Well, it didn't sound quite as bad as I thought it would, although it wasn't anything special. But it was a fun two day near zero cost project.
 
You could use them in this circuit just swap the tip36's with the 2n3055's and swap r14, r,18 (both oops), r16, r19,19 to keep them on the emitters and you'd have fairly standard Sziklai pair amp.

Probably get you 100 watts or so.

You may want to add a pot of about 30k at r5 to gain some offset control, and a 220n cap between q9,q10 bases. The mjf15031 are a bit dated but it's what I had, any similar device could be used.
 
Well there are a couple of ways to go quasi the Baxandall Diode is one as well as the triple quad like the quad 303 and while this is an oversimplification of the quad triple it works very well.

I don’t have a distortion analyzer so I can only watch the scope and I see what your talking about but at the level the sine wave zeros at 210 and 330 degrees (increasing as I lower the input) is inaudible and I'm thinking this is acceptable for a couple older transistors. Anyway it seems like fun to do things a little bit different and it sounds good.

I would like to get a distortion analyzer does anybody have a suggestion.

Thanks
 
Well it doesn't look anything like the Quad 303 triple according
to my D.Selfs PA design handbook, the quad triple doesn't need
a Baxendall diode.

Parasitic oscillations are a real pain with triples, and triples should
be avoided unless you have a high bandwidth oscilloscope IMO.

:) sreten.
 
I noticed some others who went the 3 4 route put a diode in the pre-driver stage. Would this help get rid of the crossover distortion in this design? Like maybe between r13 and q12 base or should it go between the FB and r13? I am not fully versed on the triple quad so I'm not sure how to improve this other than shooting in the dark.

Thanks
 
hello everybody,I found the attached cct somewhere in internet. looks like an Elektor baby. anybody have PCB layout for this?
 

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