I had the opportunity to hear it at AKfest 2010 earlier this year with a pair of Salk Songtowers. Show conditions are usually very challenging and good gear can often sound mediocre. This was simply not the case with the Ultravalve and Songtower combination.
The Ultravalve sounded as good or better than much of the gear I heard at the show. Some of the gear I am describing was much more money.
I am incredibly picky when it comes to tube amplifiers. Frank and AVA have an excellent sounding piece of gear. The fact that is affordable is just a bonus for value conscientious audiophiles.
Below were my comments from my AKfest show report regarding the Ultravalve.
Salk Sound and Audio by Van Alstine: This room is one that I always look forward to because they both just seem to get better and better. Jim Salk and Frank Van Alstine are two very unique individuals that make an audio match made in heaven. I feel lucky to be able to listen to their fine equipment each year at AK Fest.
The Salk Sound and AVA room was one of the largest hotel rooms at the AK Fest. It was large enough to have two separate systems with their own unique large seating areas.
The first time I visited the Salk AVA room on Saturday I had the opportunity to hear the Salk Songtowers and the Audio by Van Alstine Ulimate 70 tube amplifier paired with AVA preamp and dac. The sound of this combination had some of the best synergy I heard at the show. The music was flowing in an effortless manner and sounded natural and dynamic. It was one of the best sounds and certainly one of the best values with both products having real world pricing.
I knew how good the Salk Songtowers are before the show. The AVA Ulimate 70 tube amp is amazing. If you are in the market for a new tube amp anywhere near the price of the AVA Ultimate 70 run don't walk to the phone/computer to order one from Frank. Check this out.
I also had the chance to hear the Salk Archos open baffle speakers with the AVA Ultimate 70. This is another winning combination. I am a big fan of open baffle speakers and the Archos did not dissapoint. This version with the ribbon tweeter was very musical and provided the enveloping sound that only ob speakers provide. I do not think it would be possible to go wrong with either the Songtower or Archos with the AVA Ultimate 70
See link below if you want to see a link to the thread that the above comments came from as well as some pics.
The AVA and Salk photos are in the bottom half of page one.http://www.audiocircle.com/index.php?topic=80847.0
Hope this helps.