Ampeg V4.com

forum

You are not logged in.

#1 2014-03-08 12:54:09

waltdogg
Member
From: Hell, CA
Registered: 2010-03-04
Posts: 13

Ampeg V-4 Whistling?

I have a VT-22 that I put in a V-4 head box so it's a head now. Anyways. It whistles, only when the standby is off (amp is in 'play'), with the volume at any level and even with nothing plugged into the inputs. Tubes aren't microphonic, reverb has been replaced at some point and it has a bias mod installed. The previous owner chose JJ 7027As for the power section. It seems to be be getting worse as time goes on and the amp now has considerable amount of hum, I've had three other V-4/Bs and I don't recall if they were very noisy at all. I moved back home recently and don't have my tech to diagnose and repair the amp and I don't want to go to a new tech without being able to tell them where to look SO THEY GET IT RIGHT. Since some guys just can't make heads or tails of V-4s.


Ampeg VT-22 - Ampeg SVT-VR - Ampeg SVT 810

Offline

 

#2 2014-03-10 23:09:57

hangman
Banned
From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: Ampeg V-4 Whistling?

That's an odd one.   You could plug the ext amp out jack to a mixer and see if the whistling comes out of there.   If it does it's in the preamp if it doesn't it is in the power amp

Offline

 

#3 2014-03-11 13:35:20

waltdogg
Member
From: Hell, CA
Registered: 2010-03-04
Posts: 13

Re: Ampeg V-4 Whistling?

Oh man. I gave this a shot. It makes the amp hum and ring/whistle louder and it seems to also be coming through the PA as well. This might be a stretch but could a dirty tube socket be causing this?

Last edited by waltdogg (2014-03-12 16:37:07)


Ampeg VT-22 - Ampeg SVT-VR - Ampeg SVT 810

Offline

 

#4 2014-03-13 10:30:43

hangman
Banned
From: Seattle Washington
Registered: 2006-09-03
Posts: 1848

Re: Ampeg V-4 Whistling?

hmm,  is it the earlier version?  or the one with distortion?

Offline

 

#5 2014-03-13 12:18:55

waltdogg
Member
From: Hell, CA
Registered: 2010-03-04
Posts: 13

Re: Ampeg V-4 Whistling?

Earlier model. Yet to track down a  master volume or distortion model as clean as my '72.


Ampeg VT-22 - Ampeg SVT-VR - Ampeg SVT 810

Offline

 

#6 2014-03-15 10:34:45

waltdogg
Member
From: Hell, CA
Registered: 2010-03-04
Posts: 13

Re: Ampeg V-4 Whistling?

So far I cleaned my tube sockets by spraying a little bit of DeoxIT on the tube pins, wiped away excess and reinstalled them. I did the same with a 1/4 in. plug and all the jacks. I also opened the chassis up and noticed that metal shavings from stripped out screw holes were sitting on the pre-amp PCB, I removed those. The whistling/ringing sound seems to have stopped. Lessons in keep your amp clean?


Ampeg VT-22 - Ampeg SVT-VR - Ampeg SVT 810

Offline

 

Board footer

Powered by PunBB
© Copyright 2002–2005 Rickard Andersson