Stancor transformer

[Eric_BK]

Hi,

I came across two Stancor transformers, one which has a number stamped on it A-8053, and the other which doesn't. The one without the number is a power tranny. I believe they were from an old Oliver G150 amp. I was was wondering if they might be used for building an amp other than 6L6 or 7025 based. I'm guessing they might be too powerful for a Marshall 18 watt build.

[Phil_S]

Here's the spec on the A-8053. Send that hunk 'o junk to me. I'll dispose of it properly

Nice to have one of those. In 1948, it sold for $18.25. According to the CPI inflation calculator, that is $179 in 2014 dollars! It says it's good for 25W. That is for a hi-fi application. It is good for more in a guitar amp. How much more I don't know!

You'll need to test the unknown PT. This has been discussed here. See if you can find recent discussion on this topic.

I see this is your first post. Welcome to TAG!

[dorrisant]

The impedance would not be a good match for the EL84s in an 18w build. Also, I suspect that the voltage from that power transformer is a bit high for an 18w build as well. You could sell that set to help fund the transformer set you are looking for, but to build it with the transformers you have would be a waste of great iron.

Maybe save them for a bigger build...?

Tony

[Eric_BK]

Thanks guys. I was looking at a few amps to build around these, maybe a Fender Twin or Super Reverb, based on the wattage that the G150 had (45 - 50 watts). I'll get the specs on the PT.

[matt h]

(deleted)

[Eric_BK]

Here's a few pics of the Stancor PT and OT.

[Eric_BK]

One more of the stamp.

[Phil_S]

You can do a bit of simple exploration with the PT. I'm about 99% sure the black wires are the primary and the red wires the high voltage secondary.

Bolt the PT to a piece of wood to stabilize it. Use a screw-type terminal strip for the wire connections. Something like this: http://www.galco.com/buy/Cinch-Jones/12 ... 7Aod9xsA1g Cut the end off an extension cord if you must for a wall plug and pigtails. Rig a 1A or less slow blow fuse in between the hot leg of the wall supply and one leg of the primary. Attach the secondary wires to other terminals. Set your meter to AC volts and see what the unloaded voltage is. It will be less under load, but this is a starting point.

Then, measure the ohms across the secondary.

Post this information.

[Eric_BK]

Thanks! Will do. It may take a few days but, I'll get the info for you. Hopefully I won't short out the building doing it

[Eric_BK]

Funny trivia about these trannies, apparently the amp sat in a storage room in a church for 20 years. The condition of the trannies is amazing.

[johnnyreece]

Yeah, I was surprised how pristine they looked after scrolling down. If you go the route Matt suggested, I know RJ had some 6L6G tubes a little bit ago.

[Structo]

The Red with Yellow stripe is most likely the center tap for the secondary.

The Green with Yellow stripe is most likely the heater center tap.

Yellow - 5V rectifier heater.

One of the red's may be a bias supply.

[Eric_BK]

Before I test this, considering that a few of the tails are short, is it possible to lengthen them by soldering extra wire and heatshrinking it, or should I use small wire nuts?

[Eric_BK]

Black - Primary
Red/Yellow (according to Structo) - secondary center tap (high voltage?)
Green/Yellow (Structo) - heater/filament center tap
Yellow (Structo) - 5v Rectifer heater/filament
Red x 2 - High Voltage Secondary?
Green x 2 - ?

@Phil_S - I have the terminal strips and fuse and will do the testing. Just wanted to make sure I don't electrocute myself

@Structo - thanks for the info!

[Structo]

The second red lead is probably the bias tap, usually around 50v or so.
So one will be in the hundreds of volts and the other should be much lower.

The two solid green wires are the heater taps.