Tubes v. SS: can you mix and match?

Gentlepeoples - I was under the impression that a tube pre was always mated to a tube amp. Likewise, a SS pre would be mated to a SS amp. Of course, different makes and models of pres and amps could be mated, but I thought tubes should stick with tubes and SS should stick with SS, and never the two should meet. But this doesn't always appear to be the case with some of you. So, when and how are tubes mated with SS? Is it just a question of what sounds good? Are there any parameters at all?
Hey, Zaikesman. Thanks for your input. Let me address your insights in the order presented.

I thought passive meant 'no tone controls.' Active meant otherwise. My bad. I'm just looking for the cleanest warm sound I can get.

I'm not really a bass enthusiast (even if I seem to be), but rather one who likes sharply defined bass (I don't like it loud, just accurate). So I don't need 'punch' for my music.

So you like the tube amp route? After filing my last post to this thread, I second guessed myself and began to wonder if a tube preamp/ss amp might be a better route. Listeners seem to be dumping a lot of ss amps on the market right now (for example, I've noticed a lot of Adcom 565 monoblocks on the market for relatively cheap). Conversely, seems that the new tube amps on the market in my price range have very low power ratings and the ones that specify the requisite power are older. And as related side questions, do you leave your tube amp on all the time? And is it a relatively new feature that some preamps and have have a power-on standby circuit?

Tunes4me: have you replaced the stock tubes in your Jolida? What did you give for it, if you don't mind me asking, and what did you have before it?

Thanks folks.
Webnick, I think if you consider setting your sights a bit higher (and maybe spending a bit more) than another Adcom - even a more powerful one such as the 565 - you'll be happier in the long run. The speakers you plan to get deserve it. Get the speakers first, then audition some amps, maybe in comparsion to a 565; I don't think you'll be very hard-pressed to find something better. Most audiophiles will allocate at least as much, and often more, to the power amplification than to the speakers. Getting yourself a pair of fairly expensive and revealing speakers, and then trying to power them on the cheap, will rarely work out well - the speakers often wind up highlighting the amp's inadequacies. Listen for yourself and you'll likely agree (and don't neglect trying a speaker cable upgrade at the same time).

You are correct in thinking that you can buy more power for less money going the SS route, although that will not necessarily translate into better sound, or even sound that sounds 'more powerful' - lower-powered tube amps have a habit of exceeding expectations in this area compared to moderately-priced SS amps, so don't get bogged-down in the numbers game of counting rated wpc. Go for quality over quantity.

Bass will usually be more "sharply-defined" with equivalent-quality SS amplification than with tubes. Again, this won't automatically mean 'better' (as in 'more natural') to many listeners, but these things are why you might want to try and hear some tubed amps for yourself before committing, if you can.

To answer your other question, a tubed amp will be turned all the way off when not in use, but it will arrive at fully-warmed-up sooner after being turned on than a SS amp would if it were not on stand-by. Stand-by on preamps is not new, but is more common for SS than for tubes, and running tubes continuously can shorten their life, although so can turning them on and off frequently. Probably most audiophiles turn their tube preamps off when not it use, but there is a large contingent than leaves them on - if you get a tubed pre, you can try this and decide for yourself.
Zaikesman: thanks; very informative. My gut said to wait on a SS amp purchase: I began to wonder if the older SS amp was the way to go. And if I'm buying new, why not go with tubes. I think I'll keep the Adcom around, though. It might be useful in a multi-channel setup powering a subwoofer. What sort of power in a tube amp do you think I need for the Energy Audissey A5+2s? What about tube amp configuration? Pentode, triode? Any particular features I should look for? What manufacturers make entry level 'acceptable quality' tube amps? Thanks for your help, Z.
Webnick, I'm not sure any more what the main thrust of your question is. Listen to some amps of both types if you can. Tube amps aren't made for the mass market, so quality will be at least "acceptable" or better, but sound and quality tend to be pretty comensurate with price until you get above the price range you're likely to be looking in. As for your present speakers, I'm not qualified to offer advice on powering them, but focus on sound quality, not watts. My point is that if you want the better speakers, get a better amp than an old Adcom - be it tube or SS - and I recommend either getting the speakers first or auditioning your amp options through those speakers if you plan on buying them later. The tube options you'll want to look at in your range will not be triode, and basic stereo amps don't have many features to compare. Let your ears be your guide. :-)
I guess I was trying to understand what makes a particular tube amp a quality tube amp. I think I understand now that you were talking in general terms, and that in general, tube amps tend to be of a higher sound quality than SS amps. I'll get to some local shops and start listening to tube amps. Do you have any reservations about three channel tube amps? Do you have any reservations about the Jolida tube amps?