Tubes Asylum

Posted by Chip647 (A) on January 23, 2023 at 13:52:54

In Reply to: RE: Bias Potentiometer Issue posted by tonysco on January 23, 2023 at 10:20:23

The button just puts the meter on that tube. If the button is not making contact it will not select the tube to display on the meter. Unless you have been fiddling with the tubes potentiometer it should be OK. Probably want to get the button fixed.

Per the manual

BIAS SETUP
The bias of the valve output stage is a mixture a ½
automatic, 1/2 manual. The manual setup is done individually
on each output valves.

Pressing the left hand button marked V2 L or R the instrument
at left or right side will move the needle up the scale. At the
same time turn the potentiometer V2 L or R to place the needle
of the instrument exactly in the center between the green and
red zones of the scale.
This operation must be repeated with V3 L or R, V4 L or R .8

Finally we suggest repeating the setup procedure, as the output
stage is a parallel single ended there is a small interaction
between the output valves.