How to bias the Antique Sound Lab's 1009 monoblock

Hello out there. Can anyone help me? The last week, I bought a pair of Antique Sound Lab's 1009 power amps. These are tube monoblocks. But there's no manual!! Can anyone help me to bias this thing? It has three control knobs, plus a read-out meter. The knobs are labeled Vb1, Vb2, and Vb1-Vb2. The last knob is just a switch between Vb1 and Vb2.

Thanks in advance.

go to, the Tube Asylum (or SET asylum) and post the question there. Joseph Lau (designer for ASL) will give you the answer, and can likely send a manual too. Most likely, you switch to V1, set meter reading to 850, switch to V2, do the same - you are done.

Ed, thanks a million.