Bogen T725 Audio Transformer


In stock

SKU: BOGEN-T725 Category:


The Bogen T725 Audio Transformer is an excellent audio matching transformer for your crystal radio. This allows you to use lower impedance headphones with your crystal radio set.

This Bogen T725 has 3 black wires. The outer two black wires are 8 ohms. The inner black wire is the common (ground) connection.

Bogen T725 Specs:

Color Impedance (Ohms)
White 40K
Gray 20K
Violet 10K
Blue 5K
Green 2.5K
Yellow 1.2K
Orange 600
Red 300
Brown 150
Inner Black Common
Far left black to far right black 8 ohms


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Have a question or something to discuss?

November 16, 2017

o1A tube output transformer to speaker
Could this transformer be used in a 01A tube type vintage radio for impedance matching to a speaker?

Mike Lowe
November 16, 2017

I do not know. However, if your circuit is within the specs of the transformer you should be ok. The spec sheet can be found here