The Dumpster Transformer Topic

[wiredbecker]

Found this great transformer training this evening

[EWBrown]

The VM power trannie had a "mystery" 120VAC secondary which was wired to an "auxillary" octal socket. A little research turned this up:

Turns out that the VM console's AM/FM stereo tuner used series-strung filaments in the usual cheap "AC/DC" format, and the 120VAC winding was simply a built-in isolation trannie for the tuner.
So the power trannie had the usual primary, HV CT secondary, FOUR 6.3VAC filament windings, 5VAC rectifier winding and the 120VAC "isolation" winding. Needless to say, it had a plethora of leads, and they didn't necessarily follow any normal color coding scheme. For the 6EM7 PP amp, I just wired all four 6.3V windings in parallel, so I had more than anough current available for the 4 tubes @ 925 mA each, or 3.7A total. I figured that VM wasn't going to engineer in any unnecessary extra current, so I used all that it could offer, just to be safe.

Weird, indeed.... VM and "Mad Man Muntz" both used some rather innovative "value engineering" in their products. In other words, they made them as cheaply as humanly possible, which could still (supposedly) work well.

/ed B

[MashBill]

This thread should be "stickied". Great info!

[LinuxGuru]

I see no reasons to pick up dumpster transformer, new one custom ordered from factory should cost in USA around $100.

[EWBrown]

For me, half the fun is using free / junk / salvaged / cheap parts in my designs and builds It helps to have hamfests and swapmeets in your area, or at least good active local flea markets. Don't overlook the local dump (recycling center / transfer station) for a swap table or a scrap metal bin, if they will let you "dumpster dive".

Yard sales can be fruitful, best to llook for sales at old houses, especially if they have barns or large sheds. Newer houses and condos yield mostly used baby clothes and toys, or broken VCRs and TVs, and are generally sparse for good tube stuff ;-)

/ed B

[nyazzip]

a hundred bucks is a lot of cheap beer.
i still recall how me and a buddy furnished an entire "party room" in his mom's garage using stuff people set out on the curb for garbage pickup. you should have seen us move a couch on top of a '79 Trans Am. i STILL have the Pioneer SS receiver from those exploits

[mr2racer]

Wiredbecker,

There used to be a link to a photographed article here. It told you how to test a power transformer to get its output and approximate current rating. Do you have a copy of it? Or can you tell me how to get one? What the hell is CJB.com anyway"

Kevin

[Geek]

What the hell is CJB.com anyway

Just a hotlink-blocker.

If he can see it here, it's in his cache.

Cheers!

[Tom Bavis]

CJB.net used to offer a free domain service. So I got to use the domain audiophool.cjb.net for 10 years for free. Now their website offers no clue how to renew, no way to reach a human - perhaps they just want them all to expire. Anyway, the domain audiophool.com had become available, so I grabbed it, and my site lives on at http://www.audiophool.com. The transformer article is still there: http://www.audiophool.com/Misc/XFMR1.JPG and http://www.audiophool.com/Misc/XFMR2.JPG

[Geek]

I remember cutting my internet teeth in the 90's on CJB.net/Spaceports.com and got my first domain and hosting with their parent, Tera-Byte

Those were fun times!

Then they went public with an IPO and went spiraling down the toilet ever since