New output transformer break-in ?

[pula58]

I had a Hammnond "1750M" OT in my 50W AB763-type build. Today I swapped-out the Hammond and put in a Magnetic Components 50Watt 4/8 ohm output tranny:

http://www.classictone.net/40-18008.html

The amp now seems noticeable brighter. It might be psychological, but, I was wondering what your experiences were with output tranny break-in. Like, does an output tranny break-in at all? I would expect that it does not, but would love to hear opinions/experiences others at this forum have had.

Thanks!

P.

[Phil_S]

No moving parts. What break in?

[David Root]

OTs definitely improve in tone with age. Ask anyone who has an amp with old iron in it. Why? Gassing off/hardening of insulation varnish possibly. The highs smooth out.

Pickups improve with age, probably for similar reasons. They lose the rough highs and smooth out. I've compared new humbuckers in $1500 to $3500 Gibsons with a pair of '65 Gibson HBs, no contest, even with those old pickups in a new guitar.

No moving parts in an acoustic guitar either, but they sound better as they age too. Resins in the wood oxidize and harden, focusing clarity of tone.

Pity this doesn't apply to the human body!

[Koop]

An acoustic guitar actually does have moving parts. I was thinking about capacitors though, they're said to have a break-in period and I don't believe they have moving parts.

[David Root]

The strings and the top mostly, OK. They still improve with age, because the woods change with age. 5 years for a mahogany body, maybe 15 for rosewood.

Capacitors, and resistors, are widely believed to have break-in periods. Being subject to electrical voltages and currents, AC and DC, over time this causes changes we call break-in. Both components definitely change with age, some more than others depending on the materials and methods of construction. Values drift up or down, mostly up in my experience.

[Reeltarded]

Pity this doesn't apply to the human body!

hahahahah... Speak for yourself... My resins have hardened.. I'm fin.. ouch.. Ok, so I might be a little stiff, but I can still get around prett.. ouch...

Ok, so I have some joint trouble.

[Cliff Schecht]

The laminates of a EI core transformer are made of some form of iron oxide. With age the layers literally rust together which surely changes how the ferrite core reacts to magnetizing currents. I could see this being worse in grain aligned steels but don't quote me on this yet (I need to call in the experts on this one, gimme a day or two!).

There are also the changes in the other construction materials, the paper insulation and magnet wire specifically, that must be taken into account. Both of these are things that degrade over time (copper wire corrodes, paper takes on moisture) and change in their electrical properties. While these changes may be for the worst in terms of mechanical stability, there again is probably an audible effect that I don't think I've ever seen discussed.

I use old hifi iron (Stancor mostly) in almost all of my builds and can attest to the fact that old iron sounds great. I don't necessarily think it's because of the age as much as the sheer quality of the design and construction but I'm yet to have one of them fail on me (granted I try to treat my stuff nicely). Even in old guitar amp designs, I really think it's the construction methods and design choices that make old "classic" transformers sound great, not the age.

Or perhaps there are flaws in these old transformer designs that are accentuated by the highly non-linear distortions present in a guitar amp. Ignoring the effects of undersized iron (*looks at Leo*), different transformers react differently when operated at high flux densities. Although I typically look at the first few stages components having the biggest effect on the sound, when you are pushing an amplifier into distortion any component nonlinearities will be accentuated to some degree. Of course negative feedback is meant to reduce this but it can only do so much (and is sort of unpredictable) under heavily distorted situations.

[Cliff Schecht]

To the OP's point with one transformer being brighter than another: You have to look at all of the factors here. What is the frequency response of the two transformers? What is the core material used (grain aligned steels, etc..)? What is the interwinding capacitance? What is the real part of the impedance? There are lots of subtle things that we tend to ignore that do have an influence on your amps sound. Some people call it mojo but I say if you can't measure it, it's not there! The real performance of output transformers tends to get swamped by BS and blanket statements, the same marketing hype that the rest of the guitar world deals with really. Let your ears be the final judge, if it pleases you aurally then you've done your job as an amp builder.

FWIW I personally find Mercury's way of business almost offensive. Almost no information available on their products yet their charge three times the price. What are they, Apple?

[Reeltarded]

Sometimes the thing that has to break-in is our ears too. You get used to a thing and find the beauty in it, or not.. things grow on us. It's not overtly bright, just more umm articulate... maybe.

Give it a chance! Let the transformer live!

[Cantplay]

As the transformer heat cycles a few times it will change slightly. It expands and contracts and takes slight change as the windings shift and relax.

John

[Diablo1]

I can't believe there is any break-in on a transformer. There can be very slight changes in the steel as it heats and ages over years of time. But I doubt you could measure or hear the changes through the speaker. If you sub one transformer for another, the reason they sound different is they have different number of windings, different type and amount of steel. The two transformers also may have a different turns ratio and impedance, so the output tubes operate on different load lines.

[Phil_S]

I can't believe there is any break-in on a transformer.

Someone ought to do a scientific study. I expect what will be found is some subtle change, but not enough to account for any meaningful audible difference.

I believe, after they are varnished, they are baked. They've already been "stretched" at the factory.

[benitor]

OTs definitely improve in tone with age. Ask anyone who has an amp with old iron in it. Why? Gassing off/hardening of insulation varnish possibly. The highs smooth out.

Pickups improve with age, probably for similar reasons. They lose the rough highs and smooth out. I've compared new humbuckers in $1500 to $3500 Gibsons with a pair of '65 Gibson HBs, no contest, even with those old pickups in a new guitar.

No moving parts in an acoustic guitar either, but they sound better as they age too. Resins in the wood oxidize and harden, focusing clarity of tone.

Pity this doesn't apply to the human body!

hi David,
where did you get the information that magnetic iron suitable for transformer changes its properties after time?
Please do not be confused with permanent magnets used for PickUps.
Transformer iron is a different material from PU magnets and has got very different magnetic behaviour.
IMO the differences in tone that you hear are for sure due to something else, f.i. the quality of iron produced 50 years ago is of course different from the one produced today, old speakers sound different due to suspension elasticity, and more....
regards
benitor

[pula58]

HI,
OP here.

I guess what I was trying to ask is whether I might like the tone of my amp with the new OT once the OT breaks-in (if OT break -in is a real effect).
Obviously the new OT sounds different from the one I had in there before(it is, of course, a different transformer). But the question is, will the brightness of the new OT wear-off a little, for example: in a few months time?

[gldtp99]

HI,
OP here.

I guess what I was trying to ask is whether I might like the tone of my amp with the new OT once the OT breaks-in (if OT break -in is a real effect).
Obviously the new OT sounds different from the one I had in there before(it is, of course, a different transformer). But the question is, will the brightness of the new OT wear-off a little, for example: in a few months time?

You probably just like the sound of the Hammond over the MC--- it can be that simple. They're talking about an older transformer that has yrs (if not decades) of use/age sounding different than it did when it was new--- it probably does.
But your MC transformer isn't going to magically 'break in" and sound drastically different with a few hrs of use----- if you like the sound of the Hammond better, put it back in...........................gldtp99