Providing Output Protection for an Old Amp

[Drone]

I have an old H&H S500D amp, that I brought with me from the old country. It worked great until I found the service manual, and rewired it for 120V rather than using a step-up transformer. Shortly thereafter one of the modules went DC and melted my speaker, which I have since found is a common problem.

Recommendations to prevent this include using a capacitor on the output to prevent the amp passing DC in the event of failure, but I can't find any idea of how big a cap to use. I have a Peavey Century that uses 1000uF on the output of the amp, scaling that up I'd need 1000uF at 250V, too large or not large enough?

Ideally I'd like to fit the caps inside the current chassis, and just run the pigtail that comes from the output of the power module to the cap, and the cap to the output banana.

I'm also a bit concerned about putting a cap inline with an inductor, won't this do weird things to the output and maybe cause oscillations?

[Drone]

Bueller