step up for mc

You've got it right, Herman. Those very tiny variations in frequency aren't always going to be able to be reproduced on the other windings. Now, put those tiny fluctuations on an even smaller signal and they really get lost. It's a smoothing effect.

Like I said, I've never heard of a lower amplitude limit on a transformer. Anything to support your position other than your somewhat un-scientific explanation?

You're putting words in my mouth, Herman. I said nothing about a lower amplitude limit. The entire signal does not get through a transformer intact and what does get through is changed. It is even more evident with low output MC cartridges. If you've ever heard a well implemented SS gain stage you'll understand what I'm talking about.

That's not to say the signal is not being changed in a FET stage. But to date, it is the best sounding solution I've heard. Not to say I've heard 'em all by any means.

Ok, three things.

1. I am talking about high quality transformers.

2. High quality transformers only act as filters at very very low frequencies, like <5Hz, which is a positive thing in stereos, and at very high frequencies which isn't a problem for music.

3. Every circuit component in the world has a bandpass characteristic. Nothing is perfect so nothing has infinite bandwidth in either direction.

As you and I have already said, it's all about implementation. But you can't deny the elegant simplicity with which a transformer gets the job done.

By the way Dan, how do you like your tube amp's transformers? ;)

Arthur

Dan, I guess I misinterpreted your post but in my world signal level = amplitude. I don't see what else it could mean.

Below a certain signal level the transformers will act as a filter because some of the minute changes in the original MC signal will be insufficient to induce them in the secondary windings. The result is a loss of low level detail.

I've owned and heard some of the most highly regarded SS and tube phono stages that did not use transformers (including Aesthetix and Pass Xono) and my present one that does, among others. To my ear the transformer stages were better.

Back to the original question. Your choices are very limited for a stand alone active stage to boost the signal so your MM stage can use an MC. CJ used to make one a long time ago but I don't know of any others. I think you will be very happy with a quality transformer.