Troubleshoot BF Deluxe Reverb with original parts

[jlatrace]

I have an all original 1965 Blackface Deluxe Reverb that is the best sounding BF I have ever heard.

However, it has started putting out a single repeating (like digital delay) sound when the amp is pushed hard. The sound is in both channels and is in the register of Db, a 3rd above A 440. I think this is the original filter caps failing.

Also, at the same time, the amp breaks up unmusically in the same register (Db) when pushed, but only in the reverb channel. While I think this most likely is a bad preamp tube, I wanted you to know it began with the prior issue.

I am looking for confirmation of or advice concerning my diagnosis. While I am an experienced hobby amp builder, I have no experience trouble shooting vintage amps and value this site's input.

Thanks for the help.

[hasserl]

Well, I don't know if the filter caps are giving you the trouble you described or not, it's possible (on the Reverb channel it may be an electrolytic cathode bypas cap). But you've got forty plus years on the original caps, why screw around debating whether they are the cullprit or not, change them. You're on borrowed time now, just get it done. With fresh caps, a three prong cord and maybe some new tubes, now you can start doing some troubleshooting if you've still got a problem.