rust on output transformer?

[jzucker]

Does this automatically mean problems if there is rust on the windings?

[HipKitty]

It depends on the amount of rust penetration. I had a SF Bassman 50 come in that has lived through a flood. The customer wanted...short of demanding...that he wanted to keep the tranny's stock. Looking at the amp, I honestly had my doubts...checking the voltages, everyhting was within spec, so, the tranny's stayed and have been doing regular duty 3 nights a week without fail for the last 4 years.

[recto-robbie]

Not a pro on this subject but ive seen many brand new amps still in the store with rust on their trannies.
I dont mean flaking off rust,, just a slight surface rust.

[brad347]

I'm not sure there's a hard and fast rule about it. Sometimes it can be fine, sometimes not. If every amp with rusted transformers were taken out of service, I'd bet we'd have a lot fewer amps in the world.

[v-verb]

Go to the FAQ's om Mercurymagnetics.com.

Here's an excerpt: "What’s this mean in plain English? Back in the early years, manufacturers of laminations intentionally exposed their iron to moist air to encourage rust to naturally form on the surfaces as an insulator! Like a fine patina on an antique bronze the rust on your transformer could be viewed as badge of honor. Assuming that your transformer doesn't have other problems like coil (http://mercurymagnetics.com/pages/nav/FAQ.htm#coil) damage from excessive moisture exposure (common with paper bobbins (http://mercurymagnetics.com/pages/nav/FAQ.htm#bobbin)), you can actually expect some improvements in output transformer (http://mercurymagnetics.com/pages/nav/FAQ.htm#Output_Transformer) tone and lower losses in power transformers as rust develops."

[brad347]

how about that shit. Never heard that before. But the Mercury folks know their stuff.

[v-verb]

Yep - I used to stress about light rust on trannies - no longer.

[Structo]

That is strange, as I have always thought (or been told) that if the steel or iron laminations of the core of the transformer has rust invading it, it can degrade the properties and thus the performance of a transformer.
Live and learn ( I guess).

[guitarsnguns04]

beware of eddy currents...lol

[nitehawk55]

Rusty tranny = reliced amp :)

[jh45gun]

I have never seen where rust ever helped anything except for the browning of gun parts which browning and blueing is a controled rust process to help preserve the metal. Maybe Mercury does not coat their trannies so they rust, so they came up with that story so folks would not worry if they got a rusty tranny. Just a guess on my part as I never have seen a Mercury Tranny. Like I said this is a guess on my part so if I am wrong ok.

[SatelliteAmps]

They coat them as well as everyone else. I've never found a single brand that didn't rust. The Mercury FAQ is pretty correct.

[jzucker]

i would think if nothing else, rust would be conductive between wraps. That can't be good.

[brad347]

i would think if nothing else, rust would be conductive between wraps. That can't be good.

Iron oxide is non-conductive.

[jh45gun]

They coat them as well as everyone else. I've never found a single brand that didn't rust. The Mercury FAQ is pretty correct.


OK that shoots that theory LOL