2. amps-preamps
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Tube amplifiers and interstage transformers

Hi,

I have seen that a lot of very expensive tube amplifiers use interstage transformers to handle impedance between stages. There are other two methods to handle impedance between stages: capacitor coupling and RC. I would like to know if somebody with more knowledge can explain the difference in the sound of these 3 styles.

Somehow, it looks like some of the most expensive SET amplifiers have interstage transformers like Audio Note or Shindo.

I also read about the highly regarded amity and karna amplifiers that D Olsen built and they have also interstage transformers.

So, what are the benefits of using interstage transformers?

Thanks

Alan
alanbrain

Showing 1 response by larryi

larryi
4,326 posts
 
I am sure that one can find a lot of people in either camps -- those that hate "iron" (limited bandwidth, phase shifts, etc) and those that hate caps. I have not personally experimented with design, so I cannot speak to theoretical advantages. It just happens to be the case that the amps I like are in the "lot of iron" camp. I have a pair of Audionote (uk) Kageki amps. These are interstage coupled.

I also own a pushpull amp based on an old Western Electric 133-A design, and a linestage that is also based on a Western Electric design. The linestage has input transformers and output transformers (no caps other than in the power supply) and the amp has input transformers, and again, no caps other than in the power supply.

My phonostage has a step up transformer in lieu of an active gain stage for low output moving coils.
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