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    Building, troubleshooting and testing of these amplifiers should only be
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    the safety precautions around high voltages.

Roberts 770x / Akai M8 Tube Amplifier Question

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Hi everyone,

Long time lurker of this forum and have learned so much useful information, so first off want to say thanks to all of those who share their knowledge and experience.

I have a Roberts 770x (same as Akai M8) reel to reel that I was using the tube preamplifiers as a stereo pre amp. I use the line inputs in record mode. This morning while running some music through them I accidentally pressed the "Sound on Sound" button and instantly both channels VU meters went right up and produced a loud low-frequency rumbling feedback. I quickly switched it off the unit, but now the right channel line input produces no signal and when the volume is turned up the loud rumble comes back and also comes out the left channel as I increase the volume of the left. :no::no::no:

Any ideas what could be going on?

I have an Akai M8 and another Roberts 770x that both have 1 working amplifier- as a novice would I be able to remove and swap in a working right channel amplifier?

Thanks in advance and I look forward to hearing your thoughts/suggestions!

-Jeff
 
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I do not have hands on experience, but everything I've seen says the Akai M8 electronics is listenable.

A quick look at the schematic (uploaded) indicates that a pair of monoblocks are present. I see no reason why the working stuff can't easily be separated from the inoperative stuff and a completely functional "box" be made available.

Keep your hands off that switch, in the future.

If you don't use the R2R capability, think about removing the electronics, reboxing it, and revising the switching.
 

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