Peavey Classic 50/50 transformers

[MakerDP]

I have a Peavey Classic 50/50 rackmount stereo power amp (this is NOT the Classic 50 combo amp) and I am wondering what to do with it. I bought it used about 15 years ago and I think I used it once on stage for the 2nd guitarist in my band for an outdoor show. It's been sitting in my closet ever since.

I'd like to know what you guys think I can do with it. Here are my options as I see it (there are probably more):

1) Sell it -- for about $250 if I'm lucky and can find a buyer. Don't want to ship it though.

2) Trade it in -- doubt I'd get $100 for it.

3) Use it as a power amp for my computer sound. I have a really nice pair of JBL bookshelf speakers to pair with it that will easily handle the power.

4) Raid it for the transformers, tubes and rackmount chassis. It has two nice JAN Phillips 12AT7's, a couple Sovtek 7025's and eight Sovtek EL84's. The tubes alone are worth the trade-in value and it has two 50-watt PP output transformers and quite a beefy power transformer to handle two quartets of EL84's at 400V to the plates. I have no idea what the transformer specs are and I can't find any info on the web about them. They are the exact same output transformers as the Classic 50 combo amp, there's just two of them obviously.

Do you think I could at least build a D'Mars ODS with these transformers and get it working, knowing that as I get the available cash I would replace the transformers with better ones?
 

[eleventeen]

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Kind of a cool piece. As long as you can work in a mildly confined space, I see no reason why you could not make a single channel guitar amp out of it, although before I did that, I think I would try some pedals in front of one of the channels and leave the amp alone just because of the notion that: right now, you have a "something". If you start to tear it apart, until you successfully make another "something" out of it, you have a "nothing".


The computer speaker thing is also an idea. I dunno, personally, I kind of prefer a solid-state tuner-amplifier for that kind of application, some used piece of junk you might get at a garage sale for $25.

It's also possible that if it's a "real" power amp it wants to see about a 1 volt signal as drive for each channel and your computer might not be able to supply quite that big a signal. I have not checked the specs for "input sensitivity". The cheap tuner-amp would definitely work and would have the easy already-there switching capability to choose various inputs. And it would not care if you leave it on all day. And be a radio and/or CD player when you want that for your room speakers.



A large part of the decision process is, are you willing to have a two-piece guitar amp, eg; head & speakers. You could spend a modest amount of money getting a rack case for the head and getting the speaker. It kind of depends whether your goal is to spend the least, get the D'Mars amp you seem to want, or end up with the easiest-to-deal-with package for the guitar amp you end up with. Etc; etc; I can't know which of those goals is the most important to you.

[MakerDP]

Thanks for the reply. All good stuff to think about.

The way I see it, I already have "nothing". Right now to me it's a heavy bigger-than-a-brick box taking up space. I've only used it once for guitar in the 12 to 15 years I've owned it and I won't start now.

If I take the output transformers out of the chassis and turn it over, mounting the OT and the tubes on the "bottom" of the chassis (the new top after i've turned it over) then there is actually quite a bit of room in there. It's also pre-drilled for six knobs and three switches on the faceplate and for all kinds of connections on the back. I can then either leave it as a rack-mount unit or build a head cabinet for it. I have speaker cabinets so that's not an issue for me.

[MakerDP]

I found a really good video on YouTube on how to measure the primary impedance of an unknown output transformer and came up with the following specs for the Peavey Classic 50 output transformer (also used in the Classic 50/50 power amp). I have not found this info anywhere else on the Internet, so hopefully this will help someone in the future:

Power Rating: 50W
primary : secondary
3197R : 4R tap
3258R : 8R tap
3265R : 16R tap

So basically, it's a 50W 3k2-ohm multi-tap secondary output transformer. Pretty useful item and I have two of them to use for projects! 

Should be good for a Bassman, JTM45, Plexi, etc.

I think I might try one in a D'MARS ODS build...