Sunn Beta Lead - Distorted, low output

[stereomonostereo]

It seems the same with those removed. There are a few variances from the schematic as far as transistor replacements go. There's a 2N5551 in place of the 2N4250 at Q15 and a 2N3906 in place of the MPSA43 at Q14

[g1]

Can you try removing the C13 cap that is shown across the bias transistor ?
And the transistors that were removed were not the problem so they can go back in. (Q6 and Q15).
Sorry about all this checking, I'd really like to exhaust every last possibility before modification of the bias circuit.

[stereomonostereo]

Sorry for the late reply. I've kind of had it on the back burner. I replaced C13 and there was no difference anywhere

[g1]

Allright, I'd suggest you try increasing the value of R41 a bit and see if you can get a bit of current through R18 and R21.
The way I would do it would be to lift one end of R41 and add another 5 or 10K in series with it. That way in the future any one can see a non-factory change has been made.
And just as a side note, all this business of trying to get the bias straight may end up solving the crossover distortion issue but you still may have a weak signal to deal with.