Jadis Orchestra bias adjustment

Thanks so much for the reply!

Very interesting. Obviously the second DVM is there to compare the two output tubes to each other. I guess alternatively you could just set each to the required level but I get your method as a great way to ensure that, whatever the level, they are matched. Good show.

You are careful to point out which is the first and second pot. Is there significance in which one to use to adjust the initial level and which one to do the matching?

Thanks again. Good stuff.

Jim

First, using a digital voltmeter, measure the voltage across the 5U62 resistor connected to the output transformer. Adjust the 22K ohm pot untill the meter reads between 95 and 120 mv. Using another digital voltmeter connected to each of the YELLOW wires (pin 3) of each of the output tubes on that side, and adjust the second 22k ohm pot until the reading is close to Omv. This adjustment may change the first reading, so adjust both pots until the readings are correct. Do the same for the other channel. The first 22k ohm pot is to the left of the output tubes. The second 22k ohm pot is between the output tubes. Good luck. HIGH VOLTAGES are present. PLEASE KNOW WHAT YOU ARE DOING BEFORE TRYING THIS. The above information was gleaned from a sheet accompanying my amplifier from Northstar (970) 259-6722 e-mail: northstr@frontier.net