JTM60 output transformer upgrade

[TarheelTechinTraining]

I've got a JTM60 with the original OT but I'd like to upgrade it. I've read the OT is under speced and prone to failure. I just want to fix it before it dies/quits. Thanks in advance ,Greg

[J M Fahey]

I wouldn't fix what's not broken.

The common Internet knowledge that it's "bad and unreliable" actually means that instead of 1 in 1000 , maybe 1 in 100 fails.
Or less.

And no guarantee that the aftermarket one is actually better.

Plus: ..... how old is your amp? .... 15/20 years? More?
And the original transformer is still working? .............

[Enzo]

In my last truck I had a Sears Die Hard battery. Said it was a "5-year" battery right on it. The thing worked just fine the entire time it was in the truck, something like 12 years. SHould I have replaced it at 5 years?

The thing is transformers will occasionally fail, but most don't. In fact in the repair biz, transformers are the last thing on the list of likely failures. It is unfortunate when they do, but mostly they do not fail.

Reading about amps on the internet trying to get a sense of things is like hanging around the repair counter at a Best Buy store - all you ever see is people with problems. Not only that, the things they sell the most of are also going to be the things most often repaired. Why? Because there are so many more of them than the less popular stuff.

A common human foible is to look out the window and think what you see is what the world is. A common mistake is to assume if something happens to your amp, then it must be happening to all of them. It ain't so. 5 guys chime on on some thread about an amp with a bad transformer, and it sounds like every one of the darn things must have blown up. But it was just 5. What gets lost is the 10,000 other amps of that type that did NOT blow up. One thing I teach techs to understand is there is a large difference between a part failing a lot, and that part often being at fault WHEN a failure occurs.


I am with Juan here, if the amp is 15-20 years old, and working well, why should we decide now that the transformer is going to turn unreliable. I;d say 15-20 years of working is DAMN reliable.

[The Dude]

+1 to that! Why fix something that's not broken? Again, who says the new part is going to be any more reliable?

(not necessarily for the op, rather in general) This is precisely why you won't see me responding in threads that start with "recapping an amp" or the like. The concept of wholesale replacing of perfectly good parts is silly and nonsensical to me.

[TarheelTechinTraining]

Thanks for the reality check fellas. And yeah its almost 20 years old though it has been modded it still kick butt. Once again thanks,Greg

[soundguruman]

I've got a JTM60 with the original OT but I'd like to upgrade it. I've read the OT is under speced and prone to failure. I just want to fix it before it dies/quits. Thanks in advance ,Greg

The people who complain that Marshall OT is "prone to failure"
are the people who ABUSE the amplifier.
1. incorrect speaker impedance
2. bad defect speakers
3. incorrect speaker wiring
4. bad junk speaker cable...
5. bad old tubes...
6. incorrect bias adjustments
7. ignoring proper maintenance
is almost ALWAYS the cause of failure. IF user would pay attention to all that stuff, and operate the amp CORRECTLY,
then amp would usually keep working...and OT would not fail.

BUT typical musician ignores ALL that stuff. Blames problems on amp, instead of the REAL cause. This is typical stupidity and ignorance.
Also blames tech, who works on amp...because it's an easily available scape goat...to compensate for user ignorance.

UPGRADING OT?
Transformer manufacturer promises "huge improvement," but most people would not notice anything.
Professional Musician will notice frequency response is better...low frequency is better...cleaner...
but typical user, student, will find nothing noticeable.

If the transformer is BAD, then you could buy a better one...
But replacing a good transformer...with a better one...yields very little cost effectiveness.

IF you want a "better sound," doing modifications, carefully planned, will produce a much more noticeable and cost effective improvement.
(only if it's done RIGHT, avoid HACKS!)

[g1]

Yes, any time a Marshall fails, it is because of user error.
But any failure in any other brand is due to design flaws.
What a concept to base your entire perspective on.