Q&A with Ralph Karsten of Atma-Sphere

Tubed power amplifiers,
Tubed preamplifiers
Q&A with Ralph Karsten of Atma-Sphere

Atma-Sphere Music Systems, Inc. has been making vacuum tube amplifiers since 1976. Headquartered in Saint Paul, MN, the company is known for its output transformerless (OTL) amplifiers.

What ignited your interest in the high end? Did it come from the music side or the electronics side?
My mom always played music at home. I was always taking things apart to see how they worked. Tubes were always fascinating to me. By the time I was in high school I was refurbishing old tube amps for my stereo. But my first piano lessons happened when I was four years old, and I played a variety of instruments all through school and beyond, and still do. These days I’m in a rock band playing keyboards.

How do you define the difference between hi-fi and high-end audio?
That’s easy—it’s all about intention. Hi-fi is all about money.

What was your first high-end system? What year was this?
I think that probably happened when I was introduced to Robert Fulton, who had Fulton Musical Industries (FMI). Essentially I used his model 80 for a while with the modified H/K Citation gear I was running at the time.

What kind of education did you receive?
I attended the University of Minnesota and did the lower division of the EE course before changing my program to something called University Without Walls with a focus on audio. I finished that program and also added two years at Northwestern Technical Institute to broaden things out a little.

When did your interest in tube amps, and OTLs in particular begin?
The tube interest goes way back to my earliest years. The OTL idea was my trying to give tubes the same ability as solid-state by getting rid of the transformer. I was thinking about the idea late one night and dozed off; I had a dream in which the schematic solution of how to make an OTL was presented to me. Somehow I woke up, wrote it down, and later built it. It worked as soon as I made the final connection. I was ecstatic!

What is the greatest misunderstanding that people have about this segment?
We actually sell more preamps than amps (since we made the first balanced line preamps or amps for high end, and after 27 years the balanced linestage has come of age). People outside of the high end are not surprised at all by the idea of an OTL. People inside of high end are! Outside, the big question is, “Where do you get the tubes?” Russia, China, Eastern Europe. Inside, it’s often assumed that because it’s an OTL, it must be unreliable. We’ve been in business going on 40 years as a result of our figuring out how to make OTLs as reliable as anything else!

The other big-deal question is “What about the heat from those tubes?” Well, there is heat, but it’s not so much from the number of tubes as it is the class of operation. If the amp is in Standby all day you can grab any of the power tubes and hold on to it without getting burned. But if the amp is stone cold and you turn it on full, within a minute the tubes are too hot to touch. Put another way, if you have a Class A solid-state amp it will produce about the same heat for the same power.

Are you surprised at the resiliency of high-end two-channel and the comeback of vinyl playback?
Not at all. I don’t know how long the LP will continue but it’s got a lot of life left—the period of least production was 1992–1993. The recording industry declared the LP obsolete in about 1987. I think it has suffered as a result. The LP has now been “obsolete” for nearly as long as the timeframe when it was the primary medium. Market forces being what they are, if it were really obsolete or inferior it would be long gone. But kids like it and when I ask them why, a common answer is, “It sounds better.”  

What are the greatest challenges confronting the high end today?
High-end audio exists because people got inspired by music. Maybe they heard a cool system or something when they were a kid. For high-end audio to remain vibrant, kids have to continue to be inspired because they fuel the market of music in general. We do as much as we can to be involved in the local scene, and I think any audio company should do the same.

Outside of audio, what do you do for fun?
I like to build and ride bicycles and motorbikes and I’ve been flying hang-gliders since the late 1970s. I really enjoy primitive camping and survival skills too—likely because my mom did as well when I was a kid. I love playing in my band (Thunderbolt Pagoda) too.