Ceriatone Forum

American Style => PrinzeTone => Topic started by: amphacker on May 17, 2018, 07:22:30 AM

Title: how to set bias on Prinzetone - Noob question
Post by: amphacker on May 17, 2018, 07:22:30 AM

I purchased a Prinzetone fully assembled by Ceriatone so I haven't built it myself or ventured inside the chassis.  I have a bias probe from Hoffman Amps that allows me to measure the current flowing through the power tubes on pin 8 (cathode).

The tubes are JJ 6V6S which I believe are 14W.  The 'VoltageChart' Excel document on the Ceriatone website says that pin 3 (plate) on the Prinztone power tubes is 391V.

Now, from what I can see, the calculation goes something like this:

(Wattage / Plate Voltage) x 0.7 = desirable current, therefore

14 / 391 x 0.7 = 25mA

Can anyone confirm if I'm working this out correctly, or advise if not.

Many thanks.