Author Topic: Why the mains transformer in my amp might've nlown? (Read 4746 times)

Brow · « **on:** November 23, 2005, 08:35:46 AM »

As I posted on here a few weeks ago, my Marshall JTM60 combo stopped working and I later found out that it was the power transformer that blew.

Would using a Boost pedal (such as a Fulltone Fat Boost) in the amps series FX loop have caused the Transformer damage over time?

As this was something I've been doing on occasion for the last few months, and just wondered if this may be 1 of the causes for the mains transformer suddenly blowing.

Thanx for any info.

Craig

Ratrod · « **Reply #1 on:** November 23, 2005, 11:19:02 AM »

Wouldn't a booster blow up your pre-amp first? Power attentuators are known for causing problems to the power amp stage.

When my transformer blew, my tech told me the problem has always been there. It was an extremely minor short circuit that grew bigger over time.

HJM · « **Reply #2 on:** November 23, 2005, 12:15:28 PM »

Hang on Brow - in your last post you said it was the output tranny??

tewboss · « **Reply #3 on:** November 23, 2005, 04:45:37 PM »

Quote from: Ratrod

Power attentuators are known for causing problems to the power amp stage.

Hmmm I wouldn't have thought it would have caused anymore damage than running the amp at full volume anyway.

HJM · « **Reply #4 on:** November 23, 2005, 04:48:58 PM »

Quote from: tewboss

Quote from: Ratrod
Power attentuators are known for causing problems to the power amp stage.

Hmmm I wouldn't have thought it would have caused anymore damage than running the amp at full volume anyway.

Exactly - it's just that a lot of amps will blow up if you run them at full volume all the time....

Brow · « **Reply #5 on:** November 23, 2005, 06:02:10 PM »

Quote from: HJM

Hang on Brow - in your last post you said it was the output tranny??

Yeah, it was the output tranny, Doh! sorry

HJM · « **Reply #6 on:** November 23, 2005, 06:26:19 PM »

Could be anything, probably cheapness on the part of the manufacturer

chrisola · « **Reply #7 on:** November 23, 2005, 07:24:30 PM »

always use a 'surge protection' plug to connect to the mains imo, just like with a PC. that way, no dodgy electricity supplies or spikes will harm yer amp :)

Brow · « **Reply #8 on:** November 23, 2005, 11:38:31 PM »

Quote from: chrisola

always use a 'surge protection' plug to connect to the mains imo, just like with a PC. that way, no dodgy electricity supplies or spikes will harm yer amp :)

This is 1 thing that I always do :)#

It's only a simple circuit breaker plug, but I hardly ever plug my amp in without it :)

HJM · « **Reply #9 on:** November 24, 2005, 08:49:43 AM »

A circuit breaker isn't a surge protection device - two different jobs. The breaker cuts off the supply in the event of a sudden rush of current - ie when you electrocute yourself and teh current goes through you! The surge device protects agains fast peaks in the supply voltage.

I don't bother with surge protection with valve gear, it's not as bad as computers etc (I did have to when I had a Line6 amp - it used to crash whenever there was a spike!)

Brow · « **Reply #10 on:** November 26, 2005, 03:52:52 PM »

I've always used a Circuit Breaker when I use my gear, and until now have never experienced a problem.

I've had word back from the tech, and he said that he's fitted the new valves and output tranny, but there still seems to be a problem with the Overdrive channel

I'm seriously losing my rag with this amp. I may just sell it and buy the Cornell or Matamp that I mention in my other thread :twisted: