• 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.

GE Console RC 7100 A - need some help!

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Bruce,

I'm guessing that the tube set is a 5Y3 rectifier, 2X 12AX7s, and 2X 6BQ5s.

The phenolic PCBs are junk. Salvage the "iron" and the tubes. Buy a large, deep, plain Aluminum baking pan as the new chassis.

I suggest you follow (more or less) the DECWARE SE84 model. Triode wire the O/P tubes and use 2 triodes (possibly a twin) for voltage amplification. GE used 2 small signal stages in each channel to deal with tone control losses. If you are lucky, a no NFB circuit will work. Frankly, I have my doubts about the quality of the O/P trafos. Mediocre O/P "iron" needs help from loop NFB, particularly in obtaining satisfactory bass performance. 2X 6GK5s will do nicely in a circuit with loop NFB. A single 12AV7 family type will do in a no NFB design.

The least costly way to obtain control over both listening level and channel to channel balance is to employ a pair of single (mono) log taper potentiometers.
 
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