Builder’s Profile: Anthony Roos of At Mars Amps

Tell us about the history of At Mars?

at mars 010 After playing and buying tube amps over the years the either didn’t sound right or work right, I decided to try and build something for myself so I could have some control over both of those issues. After completing one project I would put it up for sale in order the fund the next. The feedback was usually favorable after something was sold, and that’s how At Mars began



What’s your background?

I have been playing guitar and tinkering with things since I was a kid.

What was the first product you offered for sale?

The Specialist head was the first product.

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Which has been the most popular?

There are still more Specialist heads out there than anything else.

How did you come up with the idea to take tube amps from old film projectors and build them up into these great amps?

at mars2I started out building some kits and doing some mods to modern amps in the pursuit of a personal amp that I could tweak and service myself. When I felt I was ready to take another step forward I realized from research that it was a lot cheaper/easier to modify and re-purpose an old tube amp than start a build from scratch. Not knowing what kind of trouble I could get into, I wanted to use a platform that had a successful track record. I read that there was a guy in Canada who had done several conversions using filmosounds. Of course, the first one I got a hold of was the one model that was completely inappropriate for what I was trying to do. When I finally got one that would work, the guts were so ancient and tightly packed in the tiny chassis I almost immediately decided modifying it was going to be more trouble than it was worth. So, I just gutted it and built a completely new circuit inside the chassis. I showed it to a local guitar player who had come over to buy another amp I had for sale. After playing it, he wanted to buy it. So, I built another to replace it, and one thing led to another.

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What’s the difference between the Specialist and the Torque?

AR: Although they look the same on the outside and use the same tube compliment, the circuits are completely different. Among other differences the Specialist is cathode biased and Torque is adjustable fixed biased. Sonically, in a nutshell, I would say the Specialist has a more organic and spongy feel where the Torque is stiffer with a more modern break up.

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What are you working on now?

AR: There have been a lot of requests since the outset for a combo version of the amps. Since a closed back cabinet is the original benchmark sound for what I build, and the open back combo is an inherently different animal, the challenge has been to find a box shape and speaker that puts the combo, sonically, in the same territory. I think recently I have found the recipe that works pretty well. So, the plan in the coming months is to make people aware of the combos.

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Find At Mars Amplification online:




T-Bone Mathley is the host of T-Bone’s Prime Cuts on WICR 88.7 in Indianapolis. Contributing Editor for Volume Treble Bass. Music journalist,  Guitarist, Doggy Dad, Detroit Tiger fan…




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