• 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.

troubleshooting a Mingda MC34AB

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#21
It still arced over when I turned it up with no speakers connected :/
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I do not know if it still holds true, but I always thought turning on a tube amp with no speakers or a dummy load is a BIG no no........

you could try checking the resistance of your output transformer, my music angel had a similar problem to yours and as it turned out, i had an open circuit in the output transformer... it could be a capacitor, but at least checking the transformers is pretty quick and easy.
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Thanks - I will give that a shot, probably tomorrow. If it is an output transformer, I will not be a happy camper. It is dual mono, so I will just compare them both to each other. Again, thanks for the idea.....
 
#24
yep, they were JJ. I am no tube expert but they seemed ok to me. Still working great. I do want to get some EL34 tubes just to roll and compare, winged c of course and there is another cheap one I want to try also.
I am just happy the amp is working and nothing was wrong internally with it. Now after I enjoy it for a bit, I am just going to have to dig in and upgrade it some. Will leave all of the multicaps alone, but the guys over on killerdac.com have an awesome drop box to add larger, better filter caps.
 
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