• 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.

health check and failure modes of large vintage oil caps, help please.

Hi, I am currently working on my poor man's 300b amplifier. I am building it in the case of an old 50's UK military power supply using the transformer and choke. It was stabilised design, and I am hoping to use two of the old smoothing capacitors as well. Both are TCC TYPE 92 1M 750v DC WKG at 60oC. one is 4 uF and one is 10 uF. I am at the point of testing the PSU and a bit anxious of resurrecting these 70+ year old components. When I first gingerly powered up on the variac monitoring the power consumption, there seemed to be a bit of instability, but it seems ok now. I have run it at reduced voltage for about 5 minutes. Apart from DC leakage, are these know for catastrophic failures. Visions of them exploding and catching fire like lithium ion batteries spewing cancerous PCBs all over the place..... They seem rust free, and don't appear to be leaking.

Opinions and wisdom please.

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I know they are not 300bs, I did say poor man's....