Unity gain with tube buffer?

If you desing a unity gain buffered preamp, what difference might there be between a tube buffer versus a SS buffer - are they both equally effective, does a tube buffer create a tube like preamp sound? What is the difference between the buffered approach and TVC/AVCs?

In this case the tube is driving an output transformer and the step down of the output transformer is why there is little if any gain. The output side can drive 50-100 feet of cable, balanced or single-ended. Yes, it will sound better than a semiconductor system- that does not change. The advantage of this system is that the transformer can be properly terminated so there is no ringing or frequency response anomalies, and at the same time the position of the volume control will not act as a tone control since it is buffered.

Sounds like an elegant solution for digital sources - less complexity should be better, or at least the idea of simplicity appeals to me.

my Red Wine Audio Isabella tube preamp has a switch
that allows it to run on 0dB or 12dB. in 0dB it is a tube buffer because it is not adding voltage gain. it is a seriously good sounding battery tube preamp and my version has the built in isabellina dac and it is a pleasure to listen to every day. not cheap but worth every penny, imo!

- Nate

How does using the Isabella without gain compare with using it with gain? I'm working on the assumption that the process of gain can only damage the source signal and if you avoid gain stages, you do yourself a favor assuming a proper impedance match between source and amp -- with or without a buffer. I just don't understand how adding gain to a signal, only to attenuate can possibly sound better than a signal that does not go through all that gain - how it can it possibly help matters assuming sufficient volatage form the source to drive the amp to full power. I've heard arguments regarding the controlling of various ICs which can present a capacitive problem for certain equipment, but isn't that addressed by having a buffer (tube or SS)?