Ampeg SVTII (non-pro) problems - help!

[Molan]

I've got a near perfect condition SVTII with a very irritating problem that I can't seem to get rid of!

It runs just fine but intermittently there's a horrible buzzing sound that drowns everything else out & sucks all the volume from the bass input.

At first I thought it was a tube problem somewhere but it's been a tube specialist for a service and he says all the tubes are perfect. He cleaned the seating and connections etc and said it sounded in pristine condition to him.

I got it home & played for maybe 10 minutes and then the buzz cut in again. I've tried moving it out of my garage where it's been stored in case it was a problem with the mains electrics as the garage is on a different circuit but that didn't cure it either.

The previous owner had it in storage for over 10 years I think so maybe that's caused something to fail.

When the buzzing kicks in I can flick the standby button off and then back on again & this often cures it - obviously not something I want to do at a gig!

The odd thing is that in between the buzzing it sounds great and I love the overall tone of this beauty.

So - any suggestions?

 

[B-string]

Has the classic sound of a failling power supply cap. Replace the electrolytic caps in the amp, any signs of bubbles or powder leaking from them is the only outward clue. They can fail internally without outward signs.

 

[anderbass]

He cleaned the seating and connections etc and said it sounded in pristine condition to him.

Sounds like your intermittent problem wasn't acting up when he tested it. If you think he's trully qualified to repair this particular model, I'd suggest you give him another shot at finding the problem.

This model has serveral factory recommended updates your tech may not be aware of.
This thread: http://www.talkbass.com/forum/showthread.php?t=303286 has links to these updates plus the schematics, and some other issues my amp tech repaired on my SVT-II that may really help your tech do the repairs. I'd suggest forwarding the info/thread to him.

 

[Molan]

Sounds like your intermittent problem wasn't acting up when he tested it. If you think he's trully qualified to repair this particular model, I'd suggest you give him another shot at finding the problem.

He's a specialist tube man but I think this may be beyond him really. Looks like I'll need to find a better tech

 

[anderbass]

As B-string suggested, it might just be a fairly simple problem, but I'd probably try posting a new thread asking for UK Ampeg tech recommendations. (It probably wouldn't hurt to ask the guys over on the SVT-II appreciation thread too, I think we got a few from your neck-o-the-woods)

I searched around a bit and didnt come up with much about UK amp tech's but here's some contact info that might hopefully leed you to an a older Ampeg tech thats serviced this model before.

LOUD Techologies Europe
Century Point, Halifax Road
Cressex
High Wycombe
HP123SL
Tel: 44-0-1494-557398

Email: [email protected]
Support Email: [email protected]

United Kingdom

 

[Jerrold Tiers]

Intermittent buzzing sounds most like a bad connection. If open, you get buzzes, if it happens to be touching, all is well.

Very typical of certain kinds of bad connection (Cracked solder joint) that are typical on the PC board type large electrolytic capacitors.... The solder looks OK, but if you look closely you see a tiny crack that goes all around the terminal of the part.

Easily fixed by re-soldering if that is indeed the problem.

The electrolytic capacitors in that unit are a newer type than the ones in the older amps, and are not so likely to be bad or dried-out as the old ones.

 

[Molan]

Thanks for the help guys

I tried just leaving the amp on standby for an hour & then playing for a while and it was fine the whole time.

Definitely worth checking out but maybe it just needs using a bit more regularly, lol.

 

[Molan]

I searched around a bit and didnt come up with much about UK amp tech's but here's some contact info that might hopefully leed you to an a older Ampeg tech thats serviced this model before.

LOUD Techologies Europe
Century Point, Halifax Road
Cressex
High Wycombe
HP123SL
Tel: 44-0-1494-557398

Email: [email protected]
Support Email: [email protected]

United Kingdom

Wow - just checked this link and it looks like they are only 12 miles from my house!

I think they are distributors as opposed to a tech service & repair division but must have a local contact for repair work, thanks so much for this

 

[svtb15]

Posted in another thread.. just want to see if anyone has an answer to this

My SVT 2 non pro just started making a sound today,while getting ready to record it..
When i take it out of standby besides the Normal Thunk noise that we all hear and is just part off it.

The Question ... The speaker cab now makes a thump noise which it never did before..... and there appears to be a low freq HUM that is constant at about 60 hz .. So if i play a B on the "A" string it gets a beating sound.. ughhhh
I was unable to use it to record today the Hum just a little too loud... at a moderate volume..
Anyone know what that may be?
Thank you