Author Topic: Model T output transformer options  (Read 5160 times)

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Offline Lungs Music

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Model T output transformer options
« on: January 29, 2008, 05:10:29 pm »
Hello, I have a '75 Model T Super (second generation) with a blown output transformer. My local amp tech says it will cost me several hundred dollars and many months of waiting to have Mercury Magnetics build me a new one. The benefit is that after they dissect and analyze mine, they will offer a replacement OT for the Model T in the future.
Has anyone sucessfully replaced the output transformer in a Model T? I've read posts on this forum about people researching the Hammond 1650T. Has anybody used this transformer? The specs say it is rated at 120 watts rms. Is that adequate for a 150 watt amp? I've found that tranformer for about $100. If it will work, I will probably go that route.
Thanks,
Jesse

Offline mckinnon audio

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Re: Model T output transformer options
« Reply #1 on: January 29, 2008, 05:57:12 pm »
  Hi there,I've had great success with Hammond trans.,both power and output types. I have used that particular trans. for replacement,but not in a Model T. Hammond trans. can be run up to their full ratings and they last forever. Still, having said that, I don't know if I'd use one in the T, I'd prob. look for a rewind job,good luck Mel.

Offline Lungs Music

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Re: Model T output transformer options
« Reply #2 on: January 30, 2008, 02:03:00 pm »
Thanks Mel, I think what I'll do is order the Hammond transformer and use that until I can afford the rewind from Mercury. I'd like to get this thing working right away. I found another source that said the 1650T can handle from 120-180 watts. I'll try that, if it doesn't work then I should only be out $100. I believe I also have to find another impedence selector switch, but that shouldn't be a problem.

Offline cromag

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Re: Model T output transformer options
« Reply #3 on: January 30, 2008, 04:05:37 pm »
i ran in to this problem myself awhile back.   there is no known "ready to drop in" aftermarket OT for a second gen model T.  i was in touch with a guy that also said his company would re-wind mine, then have the specs to be able to build them for aftermarket use.  can't remember the name now.  have to check my email.  but it was going to be rather pricey.  upwards of 500 bucks.   then as it turned out (thanks to joeaarthur walking me through testing and replacing a few parts) my OT wasn't blown at all.   the tech i took it to didn't really know much to help me out.  that's a whole other thread....... 

Offline the_bleeding

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Re: Model T output transformer options
« Reply #4 on: February 12, 2008, 11:52:54 am »
dynaco still makes the output trans that they used in the early model t's.  Afterall, most sunn's were designed from dynakits.

Triode electronics carries them.

http://store.triodestore.com/a4dyoutr43oh.html

120$,

Offline mckinnon audio

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Re: Model T output transformer options
« Reply #5 on: February 12, 2008, 12:05:43 pm »
  Hi there,that's not the output trans. for a Model T, there isn't any 2 ohm winding and it's the "stand up" style not the "side mount" style that's in the T's.It'll prob. work in a 200S or a 2000S,though,good luck Mel.

Offline the_bleeding

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Re: Model T output transformer options
« Reply #6 on: February 12, 2008, 12:17:01 pm »
  Hi there,that's not the output trans. for a Model T, there isn't any 2 ohm winding and it's the "stand up" style not the "side mount" style that's in the T's.It'll prob. work in a 200S or a 2000S,though,good luck Mel.

well yeah, other than the 2 ohm and the side mount. does anybody really run it at 2ohms anyway?

It would probably work if you jimmied it in and ignored the 2 ohm thing heh.

does anybody ACTUALLY make a direct replacement?

Offline mckinnon audio

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Re: Model T output transformer options
« Reply #7 on: February 12, 2008, 01:46:04 pm »
  I've looked,but haven't found anything that I would actually want to use or reccommend to anyone,Mel.

Offline cromag

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Re: Model T output transformer options
« Reply #8 on: February 12, 2008, 02:29:48 pm »
as i have mentioned above.  no.  no one does make an aftermarket O.T. that is ready to drop in and go.  at least in my research.  there might just be, though.  i'm actually surprised that there isn't one available at this point.    you can't tell me that no one evr blew up a T and then decided not to replace the O.T.   maybe sunn are indestructable.

Offline EdBass

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Re: Model T output transformer options
« Reply #9 on: February 12, 2008, 05:22:26 pm »
  Hi there,that's not the output trans. for a Model T, there isn't any 2 ohm winding and it's the "stand up" style not the "side mount" style that's in the T's.It'll prob. work in a 200S or a 2000S,though,good luck Mel.

well yeah, other than the 2 ohm and the side mount. does anybody really run it at 2ohms anyway?

It would probably work if you jimmied it in and ignored the 2 ohm thing heh.

does anybody ACTUALLY make a direct replacement?

That A431 from Triode is a 60 watt transformer, designed for a pair of KT88/6550's, not a quad. It won't get the job done no matter what you do to it. I'd go with the MM repair job.
Big $$$, but sometimes you don't have other options.

Offline the_bleeding

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Re: Model T output transformer options
« Reply #10 on: February 12, 2008, 06:21:15 pm »
if i'm not mistaken, that transformer can be hooked up for 120 watts and 60 watts.  :?

Offline deathfaces

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Re: Model T output transformer options
« Reply #11 on: February 12, 2008, 10:32:09 pm »
is there an aftermarket for a first gen model t available?

Offline the_bleeding

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Re: Model T output transformer options
« Reply #12 on: February 16, 2008, 03:00:45 am »
hey, just posting about the dynaco a431.

it is not a model t replacement at allllll. Its 60watts with 2 tubes, but you can use it at 120 watts with 4 tubes but the load on the tubes will be halved, and the impedance leads will change their value to 2,4,8 ohm taps.  =/

Offline pombagira

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Re: Model T output transformer options
« Reply #13 on: March 01, 2008, 03:56:22 pm »
i have a first gen model t and today it sounded to me at least like the output transformer was saying goodbye to the land of the living. Lots of background crackling when playing the guitar, and after a while the amount of distortion when playing clean increased, although the volume didn't necessarily diminish. So what could it be, in other amps I have had, albeit they weren't not sunn amps, this has been the sign that the transformer is giving up the ghost, and compared to my second gen model t I used alongside it, it sounded so much quieter. Anyway, I took it to my amp guy here in london and he said that with regards to output transformers, that if a replacement has to be made that it might be possible to put an svt ampeg transformer in. So what do people think about that, is that really possible without it seriously effecting the quality of the amp? It seems to be that everybody has the same opinion, that getting the old transformer rewound is the only option.