| Author | Message | ||
     John Lynch |
I just got a 112-RP-65 amp and do not know where to find the resistors to check the bias. It has two EL34 tubes, and no preamp tube. On the back it says Chassis no. 2165 RP - ID 2100 - serial number DN01780. Do I have to take it apart to get to the test points. Thanks. | ||
| Steve Kennedy |
There are only two basic methods you can use to check the bias on a Music Man amp. There are no external bias test points, so if you want to do it without a special bias fixture then you would have to take the chassis out of the cabinet. There are life-threatening voltages inside any tube amp, so if you aren't comfortable in this environment, I would suggest taking the amp to a reliable amp technician. You CAN, however, buy biasing fixtures (like the one Alessandro Products sells): www.alessandro-products.com/accessories. html Their Bias & Matching Meter allows almost anyone to check bias without removing the chassis, but it costs $199.99 and not all amps have the actual bias adjustment pot exposed for outside adjustment so you might still have to get inside to make an adjustment. |