Peavey VTM 120 Bias Voltage

[tdlunsfo]

In the Tweed super:
TAD 6L6GC Str Redbase - 43mA/417v
STR387 -62mA/404v

[g1]

In the Tweed super:
TAD 6L6GC Str Redbase - 43mA/417v
STR387 -62mA/404v

Then those numbers in the Peavey seem to make more sense. Did you try the TAD's in the Peavey?

[tdlunsfo]

In VTM120:
TAD = 32mA/496v
STR387 = 56mA/491v

[g1]

So approx. 53% diss. for the TAD's in the Peavey. That's more in line with what I would expect from Peavey, but is this with or without changes to the stock circuit?

[tdlunsfo]

It has a bias pot setup but it's turned all the way down. -54v to the grids. No screen changes on this one.

[The Dude]

So approx. 53% diss. for the TAD's in the Peavey. That's more in line with what I would expect from Peavey, but is this with or without changes to the stock circuit?

I agree. Most Peaveys are biased relatively low.

[catalin gramada]

I agree. Most Peaveys are biased relatively low.

...and should be low, to avoid thermal runaway of the tubes due to common 220k grid leak resistor.