• 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.

Counterpoint SA5 problems and a question.

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I´m having two problems with my preamp. I think the first started by trying to bypass the gain controls. At the same time I had installed a new volume control due to poor tracking from the old one. To bypass the gain controls I simply disconnected the otput and input leads and soldered them together while leaving the ground connected to to controls. After turning it back on it sounded fine at low volume but after turning it up it was as though it bottomed out before the right channel cut out. I reconnected the gain controls , checked over my soldering job on the volume control and installed a set of older 6922´s before reconnecting for another try. The right channel is still out and without a schematic or local tech (southern Spain is desparately in need of a few of these valuable people) I´m at a loss as to where to look for the problem aside from going over it piece by piece. Another problem is from excessive hum from the transformer. This preamp was wired for 120v and I took the power supply to a local tranformer builder to have it switched to 220v. I can take a picture of how he wired it if necessary. It is so loud that you can hear it from the other end of the room.

My last query is to do with the kine stage and phono preamp tubes. I have a set of 4 matched 6N1P´s but have read that these have a higher current load and may not be a suitable replacement for a 6922/ECC88/6DJ8.

Any help on any or all of these problems would be greatly appreciated.

Don
 
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