All is good with the combination, Michael.
As I kind of touched on above, I was not necessarily seeking to buy a replacement amp at this time. I have used JBL drivers in several mock-up systems. All of these JBL woofers have a common characteristic in the ability to gel well with high-current amps. Therefore, I had a prejudice in thinking that a tube amp would always be lacking in a big way compared to a solid state amp. Not so much in delivering a good sound but rather by being limited in the extremes (bass, high end and dynamics). So, with this prejudice in play combined with the thought of tube maintenance, it really was a lark for me to put in an order for the Ultravalve. What I have heard since receiving it makes the purchase seem like a good decision rather than just a flirt with old technology.
I can’t effectively rate the T8 pre amp because I don’t have a deep and broad experience with all that many pre amps. I am convinced that the T8 is all it is promised to be by AVA and all that reviews have said about it in the press or in forums. What I especially like is the easy drive and the sense of liveliness that helps good source material pop out into the room. No distinct coloration or unusual sound artifacts (e.g., tube sound). It is a good match for a solid state amp that has a power supply able to deliver higher current levels with a good amount of head room.
As with the T8, I can’t really compare the Ultravalve to other tube designs. Compared with my solid state Belles and Odyssey amps, the low end is not as firm or rock solid. Not a critical deficiency by any means, just noticeable. Also, there is not quite the same amount of pressure in the room (the snap of a snare drum does not have the same bite on the air). On the other hand, the transients are not at all blurred or glaring, and the sound image is full and extends well out from center. Nothing missing in terms of musical tone and presence. A really fine attribute is where the harmonics linger in the air with a very nice and a very natural decay.
The amps work very nicely together. Some may claim a lack of overall warmth or liquidity (if that is even an appropriate word choice) but given the right source the sound is very pleasing, both lively and musical. Frank is quite right about the amp "sounding" more powerful than the rated wattage suggests.
One final note, I will not be able to use the Ultravalve year round (booo!) as the heat output is not a good fit for this home in the high of summer.
-David