2. amps-preamps
  3. 1423424336

Motorboating after tube change

I posted this on Audioasylum tubes, but I'd like to increase the knowledge base, so here I am.

I own an Aikido preamp that was built for me in 2007. Since I don't use it that much, I haven't replace the tubes till now. After I changed them out, there was clearly audible motorboating emanating from both speakers. I returned each old tube to the unit but the motorboating didn't stop. The only screwup was that when initially replacing the tubes, I accidentally installed a 5751 into the spot for a 5755.

Any ideas?

Thx,

GP
garibaldi
Post removed 
garibaldi's avatar
garibaldi OP
12 posts
 
Thanks, Guys.

Based on your responses and those on AA, I have a coincidence on my hands. Hard to believe, but there it is. Thanks for diagnosing this over the interwebs.

GP
elevick
2,638 posts
 
I had a bad internal ground which caused motorboating. It was causing a cap to overload. The cap was fine after the ground was fixed.
Post removed 
bjbcab
131 posts
 
Sad. I thought this would have some type of wedding crasher like story. :-)
More to discover