RMAF LogoI just got back from the Rocky Mountain Audio Fest in Denver, my third time there. Attendance was up from last year and the emphasis of the show is decisively two-channel - there were few “home theatre” set-ups. There were good talks on turntable set-up, room tuning, and record mastering. As with my write-up on the AES convention, the comments here reflect my audio interests and the limited time to see everything, so don’t be disappointed if your favorite vendor isn’t mentioned.

My view of the show is skewed by the fact that I know a lot of the Denver high-end audio crowd, and they were well represented at the show. Throw in other friends, such as Frank Schröder and Dave Slagle and the show became more of a place to schmooze than anything else. Still, I tried to at least stick my head into every room. Here are the highlights of some of the outstanding rooms:

Just to start out, here is a nice display of the technology that excites me (in Jeffrey Jackson’s Experience Music room):

Jimi & Tubes

Big horn speakers were in evidence - the most impressive being the Cogent electro-dynamic horns and the Azzolina horns. Here is Jim Hagerman of Hagerman Technologies with his tower amplifier and a pair of Azzolina “Gran Sfera” horns:

Vinyl is doing quite well - many rooms relying on LPs as their high-definition source. There were lots of big turntables around. Thom Mackris’s company, Galibier Audio, had a good set-up with his turntable, the Artemis Labs preamp, Lynn Olson’s latest version of his push-pull power amp, and the Azzolina speakers. The sound of Thom’s room varied over the course of the show as the speakers and equipment were tweaked, but at the peak, was quite good, if a bit lean. Here is Thom giving the spiel in his room:

Chris Brady’s company, Teres Audio had several new products. He was showing a tube preamp and beautiful power amps using the Eimac 75TL tube as a single-ended amplifier. In addition to his earlier belt-driven turntables, he has come out with a direct-drive turntable, the Certus. It uses a rather large poly-phase motor with skewed gaps to reduce cogging. Cogging is further reduced by modifying the drive waveform to smooth the torque even further. They were being played through Edgar Horns and the overall sound was outstanding. Here are a pair of the Certus turntables:

Teres Turntables

On the left-hand turntable the motor controller sits just below the turntable itself. Next down are the Artemis Labs LA-1 line amp and PH-1 phono preamp (only the PH-1 was being used), and Chris’s preamp at the bottom. Here the stator and bearing assembly of the direct-drive motor. The rotor, which is attached to the platter isn’t shown, but consists of an array of rare-earth magnets that rotate within the stator.

Teres direct-drive motor

This seems to be the year of the Eimac transmitting tube - several other companies had amplifiers based on them. The most impressive, and one of the best sounding, was the Amber Wave Audio 200-watt mono-block amplifiers. They use push-pull 304TLs and a pair of 3B28 xenon rectifiers, along with more traditional driver tubes. The implementation was excellent. They are also huge - about 28″ wide each!

Amber Wave Audio

Jeffrey Jackson and amplifier

It should be mentioned that these amplifiers using exotic and long-obsolete tubes can only be made in strictly limited numbers, due to the scarcity of the tubes. Jeffrey’s amps are custom commissions, but I hope that Amber Wave Audio has stumbled across a forgotten stash of 304TLs! There really isn’t much of an alternative for their amps.

Probably the most impressive display was the IsoMike room - in a large, high-ceiling ballroom at the hotel. There were six pairs of huge Sound Lab ProStat 922 electrostatic speakers arranged in a large 4-channel set-up. IsoMike is an interesting organization. It developed a recording system of four isolated microphones and has made a handful of jazz and classical recordings using DSD (i.e. SACDs). They are located in Ogden, Utah, and use the facilities of Weber State University there. The sound was, as expected, huge, impressive, and pretty good, but not as good as the best systems upstairs.

Just so that you don’t think that the show had only single-ended amps and horns, there were plenty of giant inefficient speakers, welder-sized solid-state amps, mediocre sound, and terrible demo music. (How much Kenny G can you take?!?). I just didn’t spend much time with these systems.

On the whole, the RMAF is one of the best audio shows I’ve been to. It is more intimate and friendly than the CES, and reflects the growing high-end audio scene in the Denver area. As Lynn Olson mentioned to me, we are in a new golden age of audio, and the RMAF really shows this vitality.