need some help identifing output trans

[mark enger]

i found a whole box of ot there old magnavox probly less than 15 watts numbers are 320130-5 t939 i also got a huge amount of nos cap sprague bumblebee tropical fich ceramics atomics just about everything

[PRNDL]

Here's how to figure the output multiplier for an unknown transformer.

Basically, you hook up an AC wall wart to the primary and measure the AC voltages on the secondary. DC voltage won’t pass through the transformer. 12 VAC is handy for power transformers, while 10 VAC makes the math easier for output transformers.

This example uses 13.7 VAC. Hook the output from the wall wart to the tube side of the transformer. Measure the speaker side with a digital VOM set on AC volts. This will give you a number like 0.4 volts (actually somewhere between .4 and .5 as my VOM doesn't show more precision than 1 decimal point). Divide this number into 13.7 and you should get number like 34.25. This is the turn ratio. If you square this number you get the impedance multiplier which in this example is 34.25 * 34.25 = 1173. If you are using a 4 ohm speaker then the impedance will be 4 * 1173 = 4692. This is just right for a champ. (Remember champs like to see around 5000 ohms impedance.)

Most people estimate the power rating by size, which along with the impedance gives a clue to what tubes it is designed for.