Top ten tube amps

With due respect to the contributors to this thread, there are not a lot of people out there who have enough meaningful experiences with enough tube amps to put together a top-ten list. What can safely be said is that the following tube amp builders, in no particular order, have a reputation for making well-built to very well-built amps that can sound very good in the right systems:

- CAT (Convergent Audio Technologies)
- VAC
- Atma-Sphere
- Lamm
- Air Tight
- Audio Valve
- BAT
- Thor

The above list is partial and derived only from what immediately comes to mind. The list is also overly simplistic, as I could also have a category for "Very model-dependent" (Audio Research, Cary), "Very era-dependent" (Jadis), "Only now playing in big leagues" (Siegfried vintage VTL), "Great stuff, but builder dead" (Audio Note Kondo), etc.

The thing to remember is that the vast majority of tube amps, regardless of their wattage ratings, will not have power supplies or output transformers of sufficiently high quality to allow them to properly control typical, modern full-range speakers; in fact, it is rare to find either a tube amp or speaker designed with the limitations of tube amps in mind (e.g., CAT amps have massive power supplies and really high quality output transformers that allow them to handle almost any load, and Verity speakers tend to have benign impedences and low phase angles that a good tube amp can handle), and they are invariably expensive. Another approach, which is an intelligent approach in my opinion, is to run a tube amp with monitors presenting an easy load (e.g., ProAc) having little output below 50 Hz. or so that are partnered with a sub.

Wavestream Kinetics V-8s

Raquel makes a very good point. For that matter, the OTLs have a limited variety of speakers for which they are best suited. Within that limit, I would certainly keep Joule on the list.

Audiojoy - I agree. Have you ever noticed the same effect with cheap boom boxes? Not the big ones that boast of Mega Bass, but the simple little ones. I've thought they have great speed / transient response on things like picked guitars and drums. I think it's the single driver and lightweight paper cones. I remember hearing a little Sony playing a recording of a guitar at a flea market, tracking it down to see what it was, and was embarrassed to myself when I found out what it was.

The following factors, which have not really been discussed in this thread, are highly relevant to any comparison of tube amps, namely, the amp's weight, the amp's price and the listener's choice of tubes.

As for tubes and output tubes in particular, their contribution to the performance and character of a tube amp is monumental -- people shouldn't say anything about the sonic character of a given tube amp unless they have spent a few hundred hours each with three or four different sets of output tubes on that amp.

If you really want to judge a tube amp in a general sense, however, the best way, in my experience, is to look at its weight and price. Much of the cost of a tube amp is determined by the cost of its output transformers and power supplies, the better output transformers and power supplies both being progressively heavier and more expensive. Although rated at only 100 watts per channel, the discontinued CAT JL-1 Limited Edition monoblocks cost $50,000, weighed 192 lbs. each, were all point-to-point wired, and could drive speakers better than monstrous solid-state amps. Why? Because they had incredible power supply capacitance (more, for example, than the 600 watt per channel ARC Reference 600 monoblocks, which, it should be noted, weigh 22 lbs. less), had outrageous output transformers that weighed 55 lbs. each and cost a fortune, and used very specially culled output tubes.

Another indicia of quality is whether the amp uses circuit boards, which make assembly less time-consuming and thus cheaper, or discreet transistors which are individually soldered in and thus more time consuming and costly to use ("point-to-point wiring"). Due to both the high cost of point-to-point wiring and general contraction over the last ten years of the two-channel tube-gear market at the expense of easier-to-operate multi-channel solid-state gear (I did not write "easier to own" -- tube amps are ultimately easier to own in my opinion, as they tend to be easier to fix if they break and basically become "new" when they are re-tubed -- some older solid-state gear cannot be fixed at all because the transistors are no longer made), it is is now hard to find a tube amp that is point-to-point wired. Highly respected manufacturers like VAC and CAT used point-to-point in the 90's, but have stopped doing it. Atma-Sphere still uses point-to-point exclusively, which is one reason why Atma-Sphere gear is expensive.

In any event, if you need a friend to help you lift it and it cost more than your Toyota, you can be pretty sure that you've got a good tube amp.