Atma-Sphere Music Systems Factory Tour
by Marc Mickelson, Doug Schneider

The neighborhood around Wheeler Street in St. Paul, Minnesota is nondescript, though nice. There are many older houses, two stories, of the type built all over the US from the 1920s to the 1950s. The streets are lined with trees and the lawns well-kept. It's a peaceful neighborhood to be sure.

But there are a few reasons to notice 160 South Wheeler. First, there are the cars parked out front on the street -- only a few, but enough that you wonder what's going on inside. Then there's the windmill in the back yard. Is it a remnant of a bygone time or its owner's progressive thinking? There are also large cardboard boxes on the front porch and smaller boxes of…vacuum tubes?

Ralph Karsten has been running Atma-Sphere from his house for 23 years, although he's only been designing and building his products full time since 1985. His house seems to fit his business and mirror the retro look of his products, but a move to a larger space is in the plans, so Ralph can have his house back. Some of the neighbors must wonder why UPS is at Ralph's door so often, but audiophiles can guess what's up: taking away new products and delivering older ones for upgrade.

Ralph's living room and dining area -- what would be the dining area -- are for audio, his system and music collection dominating the space. Atma-Sphere's current electronics line, which rarely loses products because of Ralph's commitment to upgrading, consists of three mono amps, a stereo amp and two preamps. But the first product we spied was not an output-transformerless amp or tube preamp -- Atma-Sphere's specialties -- but rather a turntable, the Atma-Sphere 208. It starts life as an Empire 208 'table, which Ralph says is "one of the most speed-stable turntables ever made." He finds the turntables on eBay, tears them down, and "works on controlling resonances." The addition of a platter mat "that would transform most turntables by itself" is the most outward change. The finished Atma-Sphere 208 costs $2500 and has a new armboard and suspension, but it retains the Empire's motor.

The work of designing and building electronics happens downstairs, an area suited to such work but certainly cramped. We walked in on what seemed like a particularly busy day, but were told it was normal. Unlike some sterile manufacturing or office space, Ralph's basement has atmosphere. There's a certain vibe to the area where the technicians labor across workbenches from each other. Each is a specialist of sorts because he's trained to build certain models. Old-world, cottage-industry charm permeates in a market where mass-produced electronics prevail. The level of involvement and near-fanaticism reminded us of Championship Vinyl, the record store depicted in the movie High Fidelity. This is a team of audio fanatics building components for discriminating listeners -- and they care. Each MA-1 Mk II.2 mono amp takes entire week to build, while the mods done to older MA-2 Mk II.2s can take even longer.

But Ralph's crew -- John, Adam, Leif and Eric -- do beautiful work that they often sign inside the chassis. The neat layout of the components and routing of the wiring has the look of art, at least to our eyes. And once you see the work that goes into each Atma-Sphere amp or preamp, you know that training someone to build them, even if he has electrical and soldering chops, is no simple task.

Atma-Sphere's technicians work in close proximity to each other.	Adam builds a MA-1 Mk II.2 amplifier.
All of the detailed work underscores the hand-crafted nature of each product.	Internal view of a MA-1 Mk II.2 amplifier shows the skill and complexity involved in creating the product.
Leif shows Marc Mickelson the intricacies of a MA-2 Mk II.2 -- currently Atma-Sphere's most powerful amp.	The signature inside a MA-2 Mk II. It was originally finished on August 14, 1997. It's now in for upgrading.

An Atma-Sphere product is designed top to bottom by Ralph Karsten himself. And even what seems to be the most simple of components can be incredibly laborious to make. For example, the volume control for the MP-3 preamp has 96 fixed resistors, while the volume control for the MP-1 takes six hours to add all of its resistors!

The MP-3's volume control is an intricate piece to complete...

...but the MP-1's volume control is even more complex.

Despite the old-fashioned craftsmanship and the use of (gasp!) tubes in the design, there is an almost contradictory sense of modernization too. Ralph began using Autocad to design his products in 1989, and he now uses it for all metal work and circuit boards. Atma-Sphere's circuit boards are made of special materials and have high-quality pads for making connections. And Ralph is especially proud of the fact that he began using audiophile-grade parts -- Caddock, Vishay, etc. -- perhaps years before anyone else. And his choices are not arbitrary -- he's listened extensively to each component and uses only the ones that perform best in his amps and preamps. Ralph joked that people call all the time and ask about modifying a pair of amps they own, adding new resistors or caps. "Don't bother," he says. "We've already done it."

We got a sneak peek, in Autocad of course, of Ralph's newest creation, the MA-3 mono amp, a two-piece, all-vacuum-tube monster with three meters and a tube tester built in. Each MA-3 will have 42 output tubes and ten driver tubes, but the amp can be run on separate banks of tubes for less power. We doubt any audiophile in his right mind would spring for such an amp and run it at less than its full capabilities, but this attribute speaks volumes about the integrity of the design. The MA-3 will also have built-in power-line conditioning that also uses tubes. The MA-3 will be available sometime in 2002. The cost? Nothing set now, but no doubt expensive!

In a break from factory-tour etiquette, our visit did not end with a listening session. Instead we were treated to a demonstration that was no less entertaining than hearing Ralph's system -- MP-3 preamp, M-60 Mk II.2 amps, Classic Audio Reproductions speakers. Instead, Ralph wanted to show us that his amps are "unconditionally stable," which has not been the case with all OTL amps. To prove his point, he first put on some percussive music and played it loud. He then took quarters and shorted the amps at the speaker terminals. The music stopped, but we saw no smoke or flashing tubes. Once Ralph removed the quarters, the music began to play again. We were impressed.

But Ralph wasn't finished. He next grabbed an oven mitt, and again while the music played at ear-bleeding levels, he began to remove output tubes from the amps. The music continued to play. He put the tubes back in. Same thing. He then explained that all of this was possible because the amps use a true differential circuit, which he is more proud of than his use of the OTL topology. We urged him to do these demos at the CES; they were the kind of things we wanted others to experience.

We also went upstairs to see Ralph's collection of studio equipment, including a cutting lathe and tube mastering console (yes, you may see an Atma-Sphere LP sometime in the future), and then out to his garage to see his collection of vintage motorcycles -- Moto Guzzi, Laverda, Indian, even a Honda Ascot. The motorcycles echoed the equipment that Ralph makes -- vintage looks but high performance.

Our visit to Ralph Karsten's house, aka Atma-Sphere, was enjoyable precisely because it wasn't a factory tour as we have come to know them. Instead, we were reminded how the SoundStage! Network operates: lots of ingenuity and hard work from down in the basement.

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To find out more about Atma-Sphere, visit www.atma-sphere.com.