sunn amp buzzing problem (fixed)

[musicismath]

I recently got a hold of a sentura II.  It was working perfectly for about 2 weeks, and now I got this buzzing/fuzz problem.

It only exist on a "g" note.  The amp can handle any note/chord except the 6 string g note.  It sounds like there are mosquitoes stuck in the speaker.  Other than that one "g" the amp sounds amazing!

I tried out other cab/amp head combination and I got it narrowed down to the sunn sentura II head.

Is this a common problem?  Is there a specific source of problem or can it be a few different things?  I know i should take it down to the local amp shop, but I thought I would run it past some of you guys here to see if anyone can help me isolate the problem.

Thank you to anyone that has any information on this.



FIXED!!!!

soundmasterg went through the amp and replaced some of the caps which really brought it to life.  There are no more issues with the amp.  It came back with more volume after all the work, to the point that my cab rattles.  Tomorrow I will reinforce the insides to prevent any audible rattle.  So far, project sunn has taught me much needed knowledge of tube amps.

Thank you again for all this great info on sunn amps.

Special thanks to soundmasterg, biltmore, and loudthud.  and of coarse the man himself, Conrad.

By the way, soundmasterg (Greg) does some of the best amp work I've ever seen!  plus he's truly a gentlemen, and a total bad ass 

[foxfire]

my guess would be that that note (assuming it's not the guitar itself buzzing) is causing one or more components in the amp to vibrate and loose connection. it could be a dirty/loose tube socket which are pretty easy to clean/tighten. if it isn't a tube then it could be one of the internal components. if feel comfortable opening it up and working on it you could chopstick it. which is simply removing the chassis from it's case and  poking/tapping all the components in the amp with a non conductive tool (like a chopstick) with the amp hooked up to a cab and on so you can hear any static/fuzz caused moving the parts. as always keep in mind that if you're not careful you could touch the wrong component with something conductive such as your skin it could kill you...if you're good at this sort of thing, you take your time, and keep one hand behind your back then it might be worth doing. on the other hand if you have a good amp guy/gal then that would be the safer bet...   

[biltmore]

He cleaned the sockets and the tube pins and the problem still exists. It's really strange how it doesn't happen on any note but a G, but it's there. It sounds REALLY nasty too when it happens. I don't think that it's anything loose, as it can still be heard when playing at a really low volume. The awful farty distortion noise only happens when you play a G, and since the amp has already been breaking up early around 3 on the volume (which I don't think the Sentura II's do that) I'm starting to wonder if something's screwed up with the 6AN8 tube or socket. It could even be one of the caps too, for that matter.

We'll probably just have to take it into the Portland Custom Shop to get worked on, as I've tried searching around on the 'net for answers and still haven't found anything yet.

[Soundmasterg]

Thanks for the kudos June....glad I could help! I hope you enjoy the amp now and welcome to tube amps and all their glory...haha.

Greg