It is currently Tue Mar 17, 2020 3:13 am

All times are UTC - 7 hours



Post new topic Reply to topic  [ 11 posts ] 
Author Message
Post subject: Left power tube becomes Hotter
Posted: Sun Jan 01, 2012 12:56 pm
Offline
Hobbyist
Hobbyist
User avatar

Joined: Wed Oct 05, 2011 10:20 am
Posts: 5
Hey guys I've been having a issue with my 06' Supersonic. The amp sounds a little "farty"
and my left power tube becomes hotter than the other. My dad has looked at it and believes one of the capacitors might have shorted, but I was wondering if anybody else has had a similar issue with any other tube amp.
Thanks in advance!


Top
Profile
Fender Play Winter Sale 2020
Post subject: Re: Left power tube becomes Hotter
Posted: Sun Jan 01, 2012 2:35 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
Maybe you ought to have the bias checked on those 6L6GC's. Could be one is passing too much current & need replacing. If this were the case, you prolly should look for a matched pair of 6L6GC's.

You can try reversing the position of the two output tubes and see if the hotter tube goes to the other socket. If not, the sockets may need contact cleaner. Or there maybe an issue with the components that supply the bias voltage. Or a leaky coupling cap on one socket.

May want to have a good tech look it over.


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Sun Jan 01, 2012 6:20 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
+1 BMW2002Ti

The SS has two test points to check the bias on each output tube. Although there is only one bias adjust for both tubes, you can at least check the balance between them with a meter.

_________________
---> "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: Left power tube becomes Hotter
Posted: Mon Jan 02, 2012 9:12 am
Offline
Hobbyist
Hobbyist
User avatar

Joined: Wed Oct 05, 2011 10:20 am
Posts: 5
Alright guys thanks, I'll see if that's the issue later today. I had switched the tubes out with 6V6's (after talking with a Fender tech to make sure it was okay) around 3 months ago and it's worked great until now.

I put some 6L6's back in and it still does the same thing, so I know it's not a bad tube.
Again thanks for the help, I'm sure with your experience I'll get it figured out.


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Mon Jan 02, 2012 4:44 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14050
Location: Province de Québec, Canada
You put 6V6 in this amp after talking to a Fender tech !!!!

The schematic show 479 volts plate voltage. 6V6 are not made to work over 350 volt . I do you adjust bias with those 6V6 ?

You are lucky those 6V6 work 3 months.

If you have to do some repair on this amp , don't go to see this guy.


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Wed Jan 04, 2012 3:24 pm
Offline
Hobbyist
Hobbyist
User avatar

Joined: Wed Oct 05, 2011 10:20 am
Posts: 5
I installed these 6v6's which can handle plate Voltage in excess of 475 plate volts:

http://www.sweetwater.com/store/detail/GT6V6SD
(Believe me, I know normal 6v6's wouldn't last no time)

Anyway, it turned out to be a burned out Resistor. Seems to work great now!
Thanks for the support!


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Wed Jan 04, 2012 4:22 pm
Offline
Rock Star
Rock Star
User avatar

Joined: Sat Jul 03, 2010 2:18 pm
Posts: 6544
You know, to help against thermal runaway--- maybe placed a matched, good tolerance 1-ohm, 1/2-watt resistor on each output power tube, instead of the cathode-to-ground strap.

You can then measure the idle bias. And if a large current draw, like a runaway power tube occurs due to overstressing the tube or whatever... the resistor will pop and save the tube and possibly other $$$ parts in your amp.


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Wed Jan 04, 2012 4:35 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Fri Feb 05, 2010 4:31 am
Posts: 14050
Location: Province de Québec, Canada
Jagstang890 wrote:
I installed these 6v6's which can handle plate Voltage in excess of 475 plate volts:

http://www.sweetwater.com/store/detail/GT6V6SD
(Believe me, I know normal 6v6's wouldn't last no time)

Anyway, it turned out to be a burned out Resistor. Seems to work great now!
Thanks for the support!


Thanks for information Jagsang890, I did not know those 6V6.


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Tue Jan 17, 2012 2:19 pm
Offline
Amateur
Amateur
User avatar

Joined: Thu Dec 29, 2011 11:46 am
Posts: 190
Location: Coupeville, WA
stratele52 wrote:
You put 6V6 in this amp after talking to a Fender tech !!!!

The schematic show 479 volts plate voltage. 6V6 are not made to work over 350 volt . I do you adjust bias with those 6V6 ?

You are lucky those 6V6 work 3 months.

If you have to do some repair on this amp , don't go to see this guy.

NO $h&^&t :shock:

have ya thought about looking into the resistors around that circuit? besides a bias tweak?

_________________
"It's not bragging if it's fact" - HABU_71


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Tue Jan 17, 2012 2:21 pm
Offline
Amateur
Amateur
User avatar

Joined: Thu Dec 29, 2011 11:46 am
Posts: 190
Location: Coupeville, WA
BMW2002Ti wrote:
You know, to help against thermal runaway--- maybe placed a matched, good tolerance 1-ohm, 1/2-watt resistor on each output power tube, instead of the cathode-to-ground strap.

You can then measure the idle bias. And if a large current draw, like a runaway power tube occurs due to overstressing the tube or whatever... the resistor will pop and save the tube and possibly other $$$ parts in your amp.


EXCELLENT advice!

_________________
"It's not bragging if it's fact" - HABU_71


Top
Profile
Post subject: Re: Left power tube becomes Hotter
Posted: Tue Jan 17, 2012 4:27 pm
Offline
Rock Icon
Rock Icon
User avatar

Joined: Tue Jun 29, 2010 1:20 pm
Posts: 9640
Location: Indiana
The SS already has two test points. :idea:

_________________
---> "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
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 11 posts ] 

All times are UTC - 7 hours

Fender Play Winter Sale 2020

Who is online

Users browsing this forum: No registered users and 1 guest


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: