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Amplifier Repair & Restoration I service, repair, and restore all brands of tube amplifiers. The amps in the picture are just a few examples of amplifiers that were either resurrected from the dead or maintained in active service. I believe in using the correct parts for the job and taking the time to do the work properly. The amps in the picture are just a few examples pieces I have had the pleasure to work on. |
Modifications I do believe that there are some modifications that are always a good idea. These are the modifications for safety, such as installing a modern three pronged power cord. Also, in fixed bias amps, replacing a fixed value resistor with an adjustment pot that allows the bias to be set to the optimum level. Modifications requested in order to improve control over the sound of an amp, such as adding master volumes and brightness controls are something that I will do after I speak with the amp owner and understand what the desired outcome is. Black Facing People ask me about "Black Facing" their silver face Fender amp. There are a lot of diffrent opinions about what this process includes. Most silver sace Fender amp circuits are nearly identical to the black face ones. The major differences are the bias adjustment circuits and the lead dress. Lead dress in many silver face amps was sloppy which resulted in noise and oscillations. Fender added some components to eliminate the oscillations but unfortunately they also drained off the tone of the amp. Most silver face amps also had a bias balancing adjustment to allow the tubes to be matched in the amp since tubes were not sold in matched pairs at the time. You could match the tubes but you could not control the amount of bias current. Reverting the bias adjustment to the BF spec will allow the bias current to be set at the desired level and the desired tone can be obtained. Only a few component values changed in the transition from black to silver face amps. In some cases, I think the changes are an improvement. As a result, the only modifications that I feel are required to bring the Black Face tone out of that Silver Face Fender is to convert the bias adjustment circuit to BF Specs and clean up the lead dress. Naturally, there are always exceptions. The exceptions are the late 70's and early 80's Fender amps that utilize the Ultra-Linear style output design. These amps are can't be modified to the black face circuit without a complete rebuild. However, they can be modified and turned into a very reliable, great sounding amp. Check back for my mod of a late 70's Pro Reverb that is from this era. Please feel free to contact me with questions about amp work you are interested in. |
P.M. Sound Technology, LLC -Custom Built Tube Amplifiers -Tube Amplifier Repair & Restoration Serving the Northern Virginia & Washington D.C. area |