Any experience with Atmasphere OTL amps? Specifically the S-30?

joeinid

joeinid

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Anyone have experience with any Atmasphere amps?

I remember hearing the Counterpoint SA-4 OTL amps over 20+ years ago and being literally blown away. I owned Counterpoint gear and loved it. My dealer at the time had a lot of reliability problems with their SA-4 OTL amps so as wonderful as they sounded, I was not prepared for all the heartache.

I assume that Atmasphere has been so refined that reliability is not an issue anymore.

Have you lived with these amps on a daily basis? Any thoughts? I’m curious what you guys think.
 
No direct experience other than hearing the guy with the huge Classic Horns every year at Axpona who used the gear.

From what I hear Atmosphere is one of those companies you can call up and talk to the owner/designer. Paul Speltz uses the gear and has made autoformers to allow it to used with a wider variety of speakers. If memory serves the OTL like high empedances.
 
Yes, power is higher on 16-18 ohm speakers as opposed to 8 or 4 ohms. I think current OTL like Linear Tube Audio is clean and clear. I know Ralph Karsten is on all the forums answering questions.
 
The Counterpoint SA-4 were awesome, if you ever get the chance to hear them driven off an SA-9 and SA-11 do it! One of the very best systems Ive heard back in the day used Atmosphere MA-1s driving Celestion SL700s--of all things. The last set of Atmospheres I heard outside of show conditions were a pr of M60 driving Sheldon Stokes rebuilt ESL 57s that I bought that very day, it was quite good.

Im sure Ralph will eventually chime in but the S30 driving 18 ohm horns looks like a slam dunk on paper. The one caveat is self-noise, the Avantgardes are ruthless in revealing hums, buzzes and other bugaboos when no signal is present.
 
That’s the Counterpoint system that absolutely floored me and changed my view of recorded music and my life forever. An absolutely incredible sound experience.

The possible noise scares me. Even with my GAT2 and its relatively high gain on the SIT3, my system is dead quiet. No issues at all.

Hmmmm.
 
I had M60 MKIII's as well as their MP3 preamp for quite some time. Ralph was fantastic to deal with, very responsive, definitely knows his stuff. He was always refining the designs and offering reasonable upgrades. They use 6SN7 variants for drivers, so there is a lot of tube rolling for those who want to do that. They're also very stable and easy to live with. The sound was highly speaker dependent, the right match was very nice (such as Merlin my VSM-MX;s at the time), others not so much. I also had Joule Electra VZN100's (OTL 6C33's) from Jud Barber. Those were very fussy with bias, hotter than you know what, noisy at times, but sounded great. Not easy to live with at all.

These days, I'd still choose an LTA Ultralinear or 40 Reference all day long. Just a solid well thought out design, good support, great sonics with proper associated speaker choices.
 
I love Atma-Sphere equipment. I have had both the MA-1 and MA-2 amps (current system). They are incredible sounding, and incredibly robust for a tube design, let alone an OTL. Ralph has done a heck of a job and provides incredible support on all of his products with tech support and upgrades for everything as he improves the designs. I have Soundlabs, and these provide a match that various solid state amps never could match. Definitely worth a listen, at minimum.
 
Thank you for the positive posts.

There’s so much I’d love to try. Not sure what is next, if anything.
 
Joe, I have a local friend that has an MP-3 preamp that was modified by Ralph to bring it close to the MP-1. He also has a pair of MA-1 monoblocks I believe. The system sounds very good despite his room being awful. I really like the Atma-sphere preamps. I have another friend (Swiss Strips) running an MP-3 with his Pass XS-100.5's. His system sounds fabulous.
 
Thank you very much. I have no doubt that the gear sounds awesome. I’ll have to try and get a demo.
 
I have a little Graaf 20OTL and absolutely love it !

Needs 8 Ohm load, so can only drive my Sf Electa Amator 1 and Aida Acoustics Galatea, but still. Fast, transparent, quiet and spooky real sounding !
 
Thank you Adam. If I remember correctly, that’s one of the holy grail amps. Very nice.
 
It is a real gem. I have been hearing great things about this amp for many years, so when an used one poped up - I bought it unheard from a dealer in Holland (paid 2000 EUR). With the right speakers, it really is up with the best.

I have Dag Momentum Stereo, MSB M202 monos, Nord PuriFi based monos - Graaf betters them all.

Easy to drive, 8 Ohm (or higher) speakers that do not dip below 6.5 Ohm, are absolutely essential for this amp.
 
Yes, higher impedance is a must. That’s an awesome statement.

I’d love to get my ears on that one.
 
puroagave said:
Im sure Ralph will eventually chime in but the S30 driving 18 ohm horns looks like a slam dunk on paper. The one caveat is self-noise, the Avantgardes are ruthless in revealing hums, buzzes and other bugaboos when no signal is present.
Click to expand...

We found that with the S-30 there was often a swept resonance occurring between the B+ transformer for the output tubes and the associated rectifiers. If you had a really efficient speaker, this meant you got a bit of buzz. Replacing the rectifiers sorted that out nicely. The thing is, depending on which rectifier we've used over 27 year history of the S-30, the noise didn't always show up. At any rate its no longer an issue. 18 ohms is a nice load for the amp and we have a number of customers using the Avantgardes, some for decades at this point. On a speaker like that, in most rooms you have unlimited power!
 
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