Wilson WP 7 with Air Tight ATM 211

While advertised as a highly efficient speaker that can be driven by lower wattage tube amps, the WP7 drops well below 3 ohms in the bass and features a high phase angle at around 60 Hz., the result being that only a small handful of tube amps will be able to control its woofers and drive the speaker with authority. In addition, the speaker's somewhat tipped up midbass would exaggerate any difficulty a tube amp would have controlling the woofers. Air Tight makes very fine gear and the WP7 is a great speaker, but you don't want to run a speaker like this with such an amp (not unless you limit yourself to chamber music).

Thanks for your response. I've seen WP7s driven by 18WPC Lamm SET gear and sounded wonderful. Are the ATM211s less capable of handling difficult loads than the Lamm ML2s?

The Lamm's use extremely expensive output transformers and have excellent power supplies, the result being that their wattage rating is largely meaningless and they can control speakers that ostensibly much more powerful tube amps cannot. I still doubt, however, that they are as quick as they need to be to accurately reproduce upright double bass on a speaker with an impedence that drops below 3 Ohms in the bass.

As for Air Tight, I think it is superb equipment, but a $10k tube amp made by a builder having Japanese labor costs is not going to have output transformers of the quality needed to control a speaker that drops below 3 ohms in the bass (output transformers are by far the biggest single cost in building a good tube amp, and really good transformers are really expensive). The $50k Air Tight Reference, however, is another story, as are Audio Valve's big Challenger monoblocks, the CAT amps and VAC's best amps. I can suggest the VAC 70/70, as it can drive low impedences (it is totally dual mono, all the way down to two separate power cords), is very transparent and can be had for $5k-$6k used, but there will still be some tubbiness to the bass.

Have you considered the darTZeel?

The Air Tights probably don't have the most robust power supplies. However, their transformers are made by Tamura -- one of the best in the industry. It probably has more to do with the design topology. I've heard good things about the darTZeels but they're out of my price range. Thanks for the feedback.