Ampeg SVT-300 bias

[Randall]

I have just re-tubed and re-capped a 1991 Ampeg SVT-300. It is a black steel rack mounted power amp, no pre-amp. Six 6550 outputs. It has two rear panel bias points with adjustment pots, and one balance control test point and pot. I can find nothing on this amp. Anyone know how to adjust these?

[Randall]

Upon further research I am thinking it should be the same as a normal SVT power section. 0.072v from point 1 to ground, and 0v from point 1 to 2. Then 0v from point 3 to ground with a 40 hz sine wave into 4 ohms. Can I get a witness?

[g1]

I thought it would be in the owners manual, but it's not. It mentions that the bias procedure is printed inside the amplifier.
Since the owners manual seemed so hard to find, here's the link:
http://www.spengler-music.co.uk/SVT11300.pdf

[Randall]

Thanks for the manual g-one. No bias procedure anywhere inside the amp that I could find, and I tore it down pretty far.

[g1]

Should be on the chassis right behind the power tubes like this:


Elektrotanya has the schematic (SVT-II, same power amp) but it is a poor scan so you can't read the bias info.

[Randall]

Oh, for F**k's sake! Yes there it is. It's under/behind the screen and I wrongly assumed it was yadda yadda consumer safety warnings about not taking it with you into the bath tub, etc. Thanks g-one!

[g1]

Found a better picture and can see the procedure is the same as for the original SVT, as you stated in post #2. The 40hz part at 25VAC output.