Using a tube amp with a Solid State preamp

you won't have a problem with impedences using a ss pre amp. you want the pre-amp output impedence to be no greater than 1/10th of the imput impedence of the amp. most ss preamps have output impedences of l ohm or less (whereas tube preamps typically have high output impedences anywhere from 500 to 3500 ohm, more or less, which require high imput impedence in the amp. tube amps typically have high impedences and will match well with eith ss or tube preamps. the same cannot be said for matching tube preamps with ss amps - thats where the trouble can be. Relax about the electrical match. However it would seem to me, sonically speaking, that you would have a much better realization of the benefits of a tube amp by using a tube preamp to go with it.

What you want to look for is an amp with a high input impedance(say, 35k ohms or higher). You will want as low
an output impedance on your pre-amp as possible. The reason for this has to do with transferring power, buffering, etc.

If you mix, most people I know will use a tube preamp and solid state power amp.

As far as what you might gain or lose with this setup, not much.

In all logical sence there will be no problem whatsoever as to mating amps(not the speakers) More impedance match to consern when you're using tube preamp with SS amp but SS pre with tube amp will never cause the problem since input impedance of tube amps are usually infinitely large compared to output impedance of SS pre(no matter if direct or transformer coupled)

Rcprince, in ideal case(something like ss-pre and tube amp)you would definitely want an output impedance to be approaching to zero and input impedance to be approaching infinity like Newbee mentioned above.

These are two cases in mixing amplification that can be argued between each other:
In case if you're using tube preamp and SS amp you have some tube signature, very often a tube midrange presence along with punchy and fast drive, sufficient current delivery onto the voice coil.
In case if you' running SS preamp with Tube amp there is certainly tube sound but more on the analytical side with more details and often better stage and imaging.

If to drow the budget vs. performance curve there are I bet the points where you rather get SS or passive preamp having a tube amp.

To my experience all tube preamps significantly colour the signal unless you go for the level of AudioNote M5 where you feel the dynamics of an active preamp and transperency of a passive at the same time.
In all other cases SS preamps in general are more transperent than tube.

Marakanetz and Newbee--you're right, I had it backwards. Thanks for the correction.

I use a Pass Labs Aleph P with a Berning ZH270; I think it sounds great. I tried my friend's BAT VK5i with the Berning and me and a couple of other guys thought it didn't work so well. Now the BAT is an EXCELLENT piece; so my point is that there can be strange interactions with any given combo.