It is currently Mon Mar 16, 2020 5:51 pm

All times are UTC - 7 hours



Post new topic Reply to topic  [ 7 posts ] 
Author Message
Post subject: Please help.
Posted: Sun May 19, 2013 8:22 am
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Tue Oct 19, 2010 7:43 pm
Posts: 523
Location: Oakland Tennessee
I have 135watt silverface twin. Serial number dates to 1981 I think. I've taken this amp to three different techs and they can't seem to solve this problem. Here's the thing. The amp plays great and sounds awesome however, after it's been on for an hour or two or sometimes it takes longer..it starts putting out this static noise. When it starts doing this the volume knob does not effect the static noise. I can turn the volume all the way down and it has no effect on it. When this happens I've noticed that the amp seems unusually hot. Now one of the techs told me that it's suppose to get hot but I'm pretty sure it shouldn't be that hot. I've had the amp cleaned and new tubes put in just two weeks ago and last night at a gig I had the amp mic'd and it started acting up again. I use a seymore Duncan Twin Tube classic pedal and I put a tube screamer in front of it(by in front I mean the tube screamer is between my guitar and the Twin Tube Classic then out to the amp). These are the only pedals I use. Does anyone know what may be going on with this amp?

_________________
"Damn Right I Got the Blues"


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Please help.
Posted: Sun May 19, 2013 11:51 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
bshane84, did the last the last tech check the idle bias of the output tubes?

How old are the power supply filter caps? Sometimes, when thye get old --- one or two stop filtering when they warm up. JME.

Good luck!


Top
Profile
Post subject: Re: Please help.
Posted: Sun May 19, 2013 3:25 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
Another possibility for the source of the noise is the Plate resistors on the PI tube, maybe even screen grid resistors on the output tubes. I would replace all of the carbon comp or carbon film resistors with good metal film resistors. And yes, a 135 watt amp is supposed to get very hot, especially around the PT and output tubes. This amp is dissipating a minimum of about 80 watts just idling, and even more while playing, that is a lot of heat and is normal.

_________________
---> "The amp should be SWITCHED OFF AND UNPLUGGED before you do this!" <---

Por favor, disculpe mi español, no se llega a la práctica con mucha frecuencia.


Top
Profile
Post subject: Re: Please help.
Posted: Sun May 19, 2013 4:53 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Wed Mar 31, 2010 12:48 am
Posts: 26417
Location: Tombstone Territory
shimmilou wrote:
Another possibility for the source of the noise is the Plate resistors on the PI tube, maybe even screen grid resistors on the output tubes. I would replace all of the carbon comp or carbon film resistors with good metal film resistors. And yes, a 135 watt amp is supposed to get very hot, especially around the PT and output tubes. This amp is dissipating a minimum of about 80 watts just idling, and even more while playing, that is a lot of heat and is normal.


+1 +1 +1!

Arjay

_________________
"Here's why reliability is job one: A great sounding amp that breaks down goes from being a favorite piece of gear to a useless piece of crap in less time than it takes to read this sentence." -- BRUCE ZINKY


Top
Profile
Post subject: Re: Please help.
Posted: Tue May 21, 2013 6:26 am
Offline
Aspiring Musician
Aspiring Musician
User avatar

Joined: Tue Oct 19, 2010 7:43 pm
Posts: 523
Location: Oakland Tennessee
I think I found where it was coming from. I took the covers off the power tubes and wiggled them with the amp turned on. There are 6 of these. Split three on each side of a metal box.( I don't know what the little box is called as I don't know a lot about electronics or tube amps) The tube in the middle of the left three and the tube on the far right of the right three both made the amp static when I wiggled them. I sprayed some CRC Electronic Cleaner in to the sockets and put them back and now it doesn't static. I hope that was it.
I was taking the amp to a tech and he told me to try this before bringing it and it seems to have worked.

_________________
"Damn Right I Got the Blues"


Top
Profile
Post subject: Re: Please help.
Posted: Tue May 21, 2013 6:53 am
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Very cool! Maybe spray the other sockets, too?


I don't know how many problems are solved with good contact cleaner. Your tech seems to be a good one.

:mrgreen:


Top
Profile
Post subject: Re: Please help.
Posted: Fri Jun 07, 2013 11:20 am
Offline
Roadie
Roadie

Joined: Sat Mar 09, 2013 12:27 pm
Posts: 207
Deoxit works wonders.


Top
Profile
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 7 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to: