Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Yosser on July 08, 2026, 12:48:39 pm

Title: Testing the frequency response of a TXOP OOOO1 output transformer
Post by: Yosser on July 08, 2026, 12:48:39 pm

I would like to test the frequency response of the above to see it it would be suitable for use in a tube hi-fi amplifier.
There are sweep generator and spectrum analyzer apps which work with a pc sound card and may help to do this.
Has anybody done this, if so, I would like some advice?
Some people insist that tube guitar amplifier output transformers are substandard because guitars have nothing above 5K and are therefore built to a cost and not to a specification
I don't believe that as quality guitar amplifier output transformers a multilayered as stability is also required.
A test would help to clarify these thoughts.

Title: Re: Testing the frequency response of a TXOP OOOO1 output transformer
Post by: pdf64 on July 08, 2026, 04:27:27 pm

I've used a scope and sig gen to check the amplitude-phase-frequency linearity of a few OTs.
Hammond provide bode plots on some of their OT model info.

If doing it yourself, the test signal power level, source impedance and load resistance are variables you'd need to consider.