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Rust on transformers


Brian M. Watson (mrroundel)
Username: mrroundel

Registered: 06-2007
Posted on Sunday, November 06, 2011 - 07:10 am:   

The hefty fee that I'm paying for having a professional replace the electrolytics, and "going through" my 212 HD 130 w/12AX7 PI, prompted me to learn more about my amps. I spent some time learning to read schematics, to some extent, and perused the site here for ideas as to why my amp might be putting out "only" 100W on high (Tech's assessment). I remembered that the 212 does show a little bit of rust occurring on the output transformer. I then checked the board for such things and it seems that folks here believe that a rusted transformer would be a negative when shopping for an amp. I then browsed around the web looking for opinions as to why that might be, and whether it is indeed the consensus opinion. I just found this article by the head dude at Mercury Magnetics. He claims that rust can actually be a good thing on transformers. In other words, he's challenging the conventional wisdom. Here's the link to that article, which looks like it ran in Vintage Guitar Magazine in '09. Food for thought?

http://www.mercurymagnetics.com/pages/ne ws/VGmag/VGAug09Hamernik.pdf
Mike Kaus (mm210)
Username: mm210

Registered: 05-2006
Posted on Wednesday, November 09, 2011 - 02:30 pm:   

Yeah, I've seen both sides of this argument and honestly don't know WHO'S right. I know a lot of people say NOT to wire brush them off but just paint them with Rustoleum. That's what I have done in the past. HAven't cleaned them off but mine weren't THAT rusty. When I've had a cust amp to repair, I won't TOUCH them because THAT'S when stuff breaks and then they want YOU to be liable. So much today is about who they can blame. If it comes in rusty, it goes out rusty. I've been burned by people who SWEAR that I did something to their amp and it's my fault, even though all I did was maybe tighten up a loose jack or clean the corrosion off a jack. I even had a guy who SWORE I swapped out his KNOBS! Like I wanted his crusty looking things. Luckily, I've gotten in the habit of snapping a digital photo of the amp as it comes in. I showed him his pics from before and of course, he folded up like a cheap suit. The old X-Files creedo-- TRUST NO ONE! Mike.