[sushimaster]

I just finished building a Dynaco/AVA Ultimate 70.
It works but the Power transformer is buzzing. Pretty noticeably I might add.
Before I upgraded to the Ultimate 70, I had no issues with the transformer, so I know it was good.
I did do the choke update if that matters. I also noticed that when I decrease the bias on the tubes all the way counter clockwise, the buzzing decreases significantly but doesn't disappear completely. Any ideas what the issue might be or where I should start my troubleshooting?
Thanks.

[Lefty052347]

I will inform Frank in the morning concerning your problem.  Please feel free to email Frank at avahifi@comcast.net with contact information or call him tomorrow for assistance.

Regards,
Dean

[sushimaster]

Ok I found the problem. It was a bad rectifier tube. But I wouldn't have known had I not switched it out with a new one.
I triple checked my work and couldn't find any mistakes. So on a hunch I changed the rectifier tube. I didn't know it could cause the Power transformer to vibrate. I guess it was faulty or old and was drawing too much current, and the transformer couldn't keep up. Learn something new everyday. Everything is sounding wonderful now. I'm listening to Steve Hoffman's remastered Nat King Cole SACD's on it right now. The sound is breathtaking. I will sleep well tonight.   

Thanks Lefty and thanks Frank!

[avahifi]

A power transformer vibrating or loudly humming, as in your case, usually indicates something after the transformer is defective and pulling way too much current.

The rectifier tube certainly was the cause of this issue.  One way to check this is to simply remove the rectifier tube, if all is well then, you can be pretty sure the issue is with the high voltage supply.

We are glad you found the problem easily.

Best regards,

Frank Van Alstine