Threshold SA/12e mechanical hum from transformers

Good day all, in the last few months I have upgraded from my Threshold SA-2s to an un-updated pair of SA/12es. Love the big Thresholds as the drive my Kappa 9's as they are supposed to be!

Anyway the 12's have an audible mechanic hum from the transformers. I am supposing that it's due to the age of the PS Caps at 30+ years. It's remarkable these days how difficult it is to find CDE capacitors but I have managed to source the 16 quite reasonably priced and in stock! Very nice.

I am going from the original rating of 27,000uF/85v to a 41,000uF/75v cap as I did also with the SA-2s. (The 2's I actually stuffed 4 per chassis to quite an audible difference.) Figuring that should work just fine.

My question for you fine folk is, I figure I should change the rectifiers as well, 2 per chassis 35A is the original, and should this be increased or just going to a fast IXYS at 35A be sufficient? Also is there somewhere else I should look to update that might be impacting the transformers cause the technical hum?

Thank you in advance!

Scott
 
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