I haven't heard the Trenner speakers and I emphasize that my earlier descriptions are of differences of degree. The Viva amp sounds beautiful and it will impress someone who hasn't a lot of experience with 845 amps as being fast, vivid and dynamic, compared with the tube amps most tube amp listeners have available to them. However, I'll also say that I've heard most of these amps through Zu speakers, which are themselves fast, dynamic and vivid, *and crossoverless*. My experience is that having a passive crossover in the signal path -- even a simple one for a 2-way -- diminishes the differences between amplifiers, particularly in perceived event speed, tone density and dynamics. The crossover is a choke point, compared to not having one. The Viva sounds slower and "voiced" to me by comparison. The Audion, more open, transparent and objective.
Now it's arguable that I might, for example, prefer a Viva amp on a Zu speaker over an Audion driving a Trenner. It's also possible that differences that are meaningful to me are too small to influence preference to someone else. And the number of 845 amp choices on the market continues to proliferate. There are more than ever, I think. But so far, while having heard many great amps (because it's hard to go wrong with an 845) I haven't heard better than Audion in an 845. Sometimes people ask me to recommend an 845 amp and I'll answer by tossing out five or six, advisng that any of them will do. But they always press for a "best." The Audion isn't cheap, nor is the new Sophia, but that's my answer.
One more point: In another thread some months back I pointed out how much can be done to improve an amp via power supply capacitors. Some amp designs are highly susceptible to beneficial alternation through recapping. Last year, Bob Hovland recapped my Audion 845 monoblocks, which further evolved every advantage the Black Shadow has over other 845s, without changing the essential character of the amp. I've heard much more transformative recaps on some other amps Bob massaged, including my Audion Golden Dream monoblocks, 300B PSET big sister to the Black Shadow. In the Golden Dream case, Bob's recap took what was already the best sounding amp I've owned (above 100 Hz) and made it not only significantly better but also rendered it effective in deep bass, where 300B amps are most problemmatic. The Golden Dream is a different take than the 845 Black Shadow, still more resolving and nuanced, but it costs more too, and packs more silver. Point is, if you have a Viva, for example, and want it to be more like I describe an Audion, send it to Bob Hovland or someone like him for an educated recap of the power supply. I heard a disappointing Tri 845 integrated. It was clearly voiced to the more traditionally romantic SET sound often heard in Japanese boutique tube electronics. But it also had many excellent qualities lurking in the mix. I have no doubt that if the owner had been willing to have the amp recapped, its performance could have been elevated to be satisfying more in the way the Audions are, for much less. Keep in mind that if your amplifiers have been priced to support channel distribution, your $10,000 amplifier has about $2,000 of cost in materials, labor and packaging. There are compromises made for economic reasons that leave some of the potential of a great design unexploited. A transformative recap might only cost a few hundred. Two electrolytics of the same rating can sound quite different, as other factors in chemistry, configuration and even shape affect their discharge characteristics. Also, there is more than one way to a destination. I generally favor the simplest circuits, but the Sophia, coming so close to the Audion, does it with more tubes, more wire, more parts than many others.
Phil
