newbie question on TUBE gears.

You need to tell us what speakers will be used. I personally love tube amps and have owned various ones for 23 years. However, I also like tube pre-amps and the well designed ones are virtually maintenance free. Maybe replace the small tubes every 3-5 years depending on how much you leave them fired up.

There are damn good SS amps such as Plinius, Ayre, etc. However, if your speakers are amenable, I'd look into tube amps and not worry about upkeep, etc. I have an EAR 890 which is about 2.5 years old and I'm using the same power (big) tubes. Importer has told me they still have another year of two left. Years ago I fretted and worried about sutff like leaving the amp on, how many times I turned it on and off, etc. I now just use it when I want (it makes beautiful music) and realize the KT90 is a very easily available tube.

Also, you might let us know what kind of music you like and how loud you listen (along with IDing the speakers being used).

By the way, I agree with everything Newbee said.

Looks like your system is more of a dedicated theater to me. I would suggest upgrading your processor to a 568. You could also gain some improvment with some accoustic panels behind your front 3 speakers. Integrating tubes into your system is not going to be easy. You could try a tube Pre/Proccessor from Cary Audio. Another option would be to buy a 2-channel tube amp and see how you like it against your Bryston amps.

1. Is it ok to mix and match SS preamp and tube poweramp?

ABSOLUTELY. IT HAPPENS ALL THE TIME. MANUFACTURERS EVEN MAKE WHAT THEY CALL HYBRID INTEGRATEDS. MUSICAL FIDELITY EVEN SELLS WHAT'S CALLED A TUBE BUFFER THAT PEOPLE CAN INSERT INTO THEIR SS SYSTEM.

2. How often do you need to replace the tubes?

YOU NEED TO REPLACE A TUBE WHEN IT FAILS PREMATURELY, DIES BECAUSE ITS DONE OR BECAUSE YOU WANT TO "ROLL" THEM.

A TUBE FAILING PREMATURELY IS RARE. I KNOW IT HAPPENS BUT IT'S NEVER HAPPENED TO ME AND I DON'T KNOW ANYONE WHO HAS HAD THIS HAPPEN. MOST TUBES WILL LAST THOUSANDS AND THOUSANDS OF HOURS. YOU WILL MOST LIKELY EITHER ROLL THE TUBES OUT OR SELL YOUR EQUIPMENT BEFORE YOU HAVE TO CHANGE A TUBE THAT HAS RUN ITS COURSE. TUBE ROLLING IS PART OF THE ALLURE OF OWNING TUBE EQUIPMENT. YOU WILL PROBABLY WANT TO EXPERIMENT WITH DIFFERENT TYPES (KT88 VS. 6550) AND/OR BRANDS.

3. How easy/hard to get extra tubes and the cost?

ANYONE CAN FIND ANY POPULAR TUBE TYPE ANYTIME. THE "HARD" PART IS EDUCATING YOURSELF ABOUT TUBE REPUTATIONS AND THEN DECIDING ON WHAT TO GET. OF COURSE, YOU'LL PROBABLY END UP TRYING DIFFERNT TYPES UNTIL YOU FIND THE ONES YOU LIKE. THERE ARE NOS TUBES THAT TEND TO BE RARE (THEY'RE NOT MAKING ANYMORE NOS TUBES!!) AND NEW TUBES THAT ARE ABUNDANT AND COST LESS. JUST LIKE ANYTHING, THERE'S A WIDE RANGE OF VARIETY AND PRICE

4. How easy/hard to replace the tubes? Is it easy enough to DIY or do you need to take it to dealers?

IF YOU CAN SCREW IN A LIGHT BULB YOU CAN REPLACE A TUBE

TRY TO GET SOMETHING THAT HAS AUTOBIAS IN THE DESIGN