• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Bogen MX-60a tune-up

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Hello,

Just had a few questions about my baby, the Bogen MX-60a. First, when I turn up the treble and the turn up the high pass filter, it begins to hiss prety loud. Also, at higher volumes it begins to pick up radio stations. The power tubes are no longer 8417's, the amp was retro-fitted for EL34's by the pevious owner. there are also 1/4" input and output jacks, and a bias adjust installed. Other than that, the schematic is accurate. Also, I would like to possibly take the TAPE/MAG input and use it as a overdrive stage for the Mic 5 input (which is the one that controls the 1/4" input). Any advice would be greatly appreciated. I also have a Bogen CHB-100 amp I would like to be made noiseless as possible too.

Thank you,

JackCHB-100
 
Bogen MX60A

Thanks for making the schematic available for this old amp. Just bought/traded for one and plan to use it for my guitar. Mostly planned to drive it with my Behringer pedal but now will build some preamp stages and try it without any outboard effects.

AngusL :D
 
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