300b lovers

I am extremely pleased the Amity, Raven, and Karna designs are having their public debut. The only people who have heard them before were very adventurous DIY builders, but now, thanks to Don and the team at Spatial Audio, we are moving steadily towards production. Don has taken the amplifiers a long way on his own initiative, and it’s been a lot of fun having him as a collaborator.

I look forward to seeing you all at the show, and even more collaborations and products in the future.

People ask me about a phono preamp. Well, no. That’s an entirely different set of skills.

Speakers? My neighbor here in Colorado, Thom Mackris of Galibier Designs (turntables), and myself are completing a high-efficiency large-format 2-way loudspeaker loosely based on the Altec Valencia and Model 19. Will it be manufactured by anyone? I have no idea.

I have a friend in the UK who has built an SQ quadraphonic decoder based on my Shadow Vector patent (1975), except realized in software and with 8 spectral bands operating in parallel. It would be a real blast from the past to hear that again ... I lost track of the handbuilt Audionics prototype in 1976.

I occasionally fantasize about a quadraphonic system using Shadow Vector, a quadraphonic Raven, and four Karna triode amplifiers powering four of my speakers. That would be fun, with sound probably much like Todd-AO 70mm movie theaters from the early Sixties.

It’s been a fun journey. A summer job at NASA in 1969, during the Apollo 11 mission, running 16mm sound projectors, the Altec sound system, and working in the darkroom. Inventing Shadow Vector, which got me the job at Audionics. Going to the UK and meeting the BBC quadraphonic team and Laurie Fincham at KEF. Building the Shadow Vector prototype and designing several speakers at Audionics. Working at Tektronix as a tech writer in the Spectrum Analyzer division, and meeting Rich Cabot, who would go on to found Audio Precision. Landing on my feet after the 1988 mass layoffs and becoming a tech writer and editor for several magazines, designing the Ariel speaker, Amity amplifier, Raven preamp, and Karna amplifier. Moving to Colorado after thirty years in the Northwest, and meeting Thom Mackris, who is my neighbor only a couple miles away.

Last but not certainly not least, my collaboration Don Sachs, which began with phone conversations and many, many emails after I bought Don’s preamp. Naturally, my preamp had to be different, with a balance control ... the dual-mono Khozmo volume control. One thing led to another, with Don curious about both the published Karna amp and the hard-to-find Symmetric Reichert, which some folks in London had built. The project evolved from there, gaining in refinement each step of the way.

Don was also curious about the Raven, so we discussed how it could be improved and brought up to date. To my surprise, he went ahead and built it, and we agreed on a cascaded power supply ... Don's favorite followed by my favorite, a VR-tube shunt regulator for each channel.

Actually Lynn said if I built the Symmetric Reichert it would be the best amp I had ever heard.  I like a challenge.   Then I decided if I was going to build it we would figure out the best way.  So we ditched the driver section and came up with a much better one, and I prefer power supplies done my way, to the max so we worked on that approach too.  A year later here we are.....

Weirdly enough, both Thom Mackris and Don Sachs came up with the 6V6 driver within hours of each other. Thom was hacking around with his SET 300B amp and swapped in the 6V6 driver and was jumping up and down about it, and Don calls the same day. OK guys, you win, tell me how it’s going.

Thom plays electric guitar and has built his own guitar amp, as well as his 300B SET for his hifi system, so he’s really into tone. The 6V6 is famous throughout the guitar community for its tone. And Don’s a big fan of the 6V6 too. I’d been casting around for a replacement for the unobtainium 45 (in matched pairs no less), and both my friends say the same thing on pretty much the same day. And yes, Don and Thom chat on the phone on a regular basis. I think they have an ESP thing going.

This degree of insight is so interesting and appreciated. I do recall the introduction of the Galibier 300b SET a few years back. Three highly regarded audio veterans sharing thoughts, ideas and concepts. This is precisely why I believe that there will always be a place for high quality well implemented tube audio components. If done right, sublime sound is the successful result.

Charles