Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pullshocks on August 05, 2025, 05:28:35 pm

Title: Did I ruin my resevoir e-cap?
Post by: pullshocks on August 05, 2025, 05:28:35 pm

Dagnabit, I applied AC for a few minutes before noticing I had the resevoir cap wired backwards.  Any chance it will still work if I rewire it correctly?


Thanks in advance.

Title: Re: Did I ruin my resevoir e-cap?
Post by: shooter on August 05, 2025, 05:33:01 pm

 :laugh:


if the guts ain't all over or there was no swelling or "warmth", maybe, but it's definitely time to order a few spares

Title: Re: Did I ruin my resevoir e-cap?
Post by: pdf64 on August 06, 2025, 05:09:49 am

A second or 2 maybe survivable, but a few minutes? It'll be wrecked.

Title: Re: Did I ruin my resevoir e-cap?
Post by: tubeswell on August 06, 2025, 01:23:07 pm

If it was a simple power supply circuit with a single cap from ground to B+, yes it likely damaged.


If the circuit called for 2x stacked caps at the reservoir position, and the cap closest to the B+ was positive/forward polarity to B+ but you put the cap closest to ground with positive polarity to ground, you’ll have made one joined up bipolar cap, which will be fine, but unusual...

Title: Re: Did I ruin my resevoir e-cap?
Post by: pullshocks on August 06, 2025, 03:02:36 pm

I'm updating the complete schematic but here is the power supply


I tried rewiring the cap, didn't like the B+ readings I got. So I replaced the cap.  Even with the 2nd cap, something is not right, low B+....


ARRRGH, as I type this I just realized the amp is still plugged into the light bulb limiter,   :laugh:   




Anyway, I think the first cap survived the insult, but I'm not going to put it back


Thanks, folks, appreciate everyone jumping in so quickly

Title: Re: Did I ruin my resevoir e-cap?
Post by: pullshocks on August 06, 2025, 04:01:46 pm

OK, I got the LBL out of the picture and things are working as they should.


Thanks again.