I purchased an Audio by van Alstine Ultimate 70 in March, 2006. I had been familiar with Frank's work since the early 1980s and had already had great results with AVA upgrades to solid state electronics (an OmegaStar PAT5 and an OmergStar 170EX). I am just as pleased as punch with my Ultimate 70, and would have reviewed it sooner, but I felt that my lack of a frame of reference would not make for a very instructive review. But I'll give it a shot anyway.
I have heard three iterations of a Stereo 70. When I became interested in the idea go going with a tube amp, it was the Untimate 70 that was responsible. I had read about it here. I had been more or less a collector of Dynaco solid state gear for many years, but I did not have a Stereo 70. I started playing around on ebay, and eventually won a stock unit. When I first plugged turned it on, I was struck by the soundstage, but the tonality of the amp was horrible - like singers holding their hands in front of their faces. I recognized that this amp needed recapped. A few weeks later I saw another amp, this refurbished by triageaudio. He keeps the units mostly stock, replacing caps and tube sockets and resoldering everything. I'm not sure why it was that I got into a bidding war on it, but I ended up paying $431 + another 30 for shipping. This unit sounded much better; had pretty good tone in addition to a great soundstage. I still use it in my 'extra' system.
But I really wanted an Ultimate 70, so I saved up and shipped the first unit off to Frank. When I got it back, I was amazed. The clarity and presence of the mids and highs was immediately impressive. Up until that point, I had been having trouble with people using the word 'sweet' in describing an amp or preamp. But the upper registers were warbling sweetly and the bass was good and tight and the tonal balance was excellent and the soundstage was even better than what I was used to with my solid state AVA rig. Then I also understood why tube sound was sometimes called 'warm' because compared to this Ultimate 70, the refurb unit had a sound that could be described as warm. This was just clear. Another term that was lost on me until that moment was 'engaging.' But with every note I heard, I keep wanting to hear how the next would sound.
I tried it with several solid state preamps and a stock PAS3, then found a deal on a Super PAS Three with the black face plate. No surprise that this is the best pairing with the Ultimate 70.
I was originally planning to someday have my refurb unit upgraded so I can run two bridged in mono, but with my degree of satisfaction with my single unit balanced against the cost of a phase inverter, I am now trying to sell the refurb unit. I told a prospective customer, "If the old stock unit is a 1 and the AVA upgrade is a 10, the refurb comes in at 6, maybe 7."
