[jtwrace]

Anyone using them?  I would like to hear any and all feeback.  I'm looking into replacing my current equipment with them.  Thanks.

[EDS_]

Anyone using them?  I would like to hear any and all feeback.  I'm looking into replacing my current equipment with them.  Thanks.

I had an older pair in my system for a while a few year ago.

Thoughts:
1. Extreme waste heat
2. Great sound when playing simple Jazz, lightish Opera or vocal centered blues or pop
3. Not as great with more complex music
4. The pair I had were old and reliable for the six or eight months I had them

[zybar]

Anyone using them?  I would like to hear any and all feeback.  I'm looking into replacing my current equipment with them.  Thanks.

Pluses:

Can really deliver the "you are there sound"
Great dimensionality and texture
Think of them as SET on steroids

Negatives:

Hot, Hot, Hot!!  Depending on the model and your room size this can be a serious issues
Careful speaker matching is a must! - 4 ohms and lower need not apply (unless you use the Speltz autoformer)
Low sensivity means careful preamp/front end matching
On older models self-biasing was a pain in the butt

I owned a pair of M-60's and did enjoy them.  I ultimately sold them as they didn't work with the system after moving away from high efficeincy, high ohm speakers.

George

[Brian Walsh]

3. Not as great with more complex music

I don't follow, because I get wonderful results on big orchestral, rock, etc. What was your associated equipment, especially speakers, and which model did you own?

4. The pair I had were old and reliable for the six or eight months I had them

That's not very long. Why did you sell them?

Speaker impedance is a consideration at least on the S-30 and M-60, somewhat less so on the MA-1. ZERO autoformers have been used successfully in some instances, for example one customer had good results with M-60s driving Martin Logan Summits.

Yes, the amps throw off some heat, but not dramatically more than solid state amps producing a significant amount of power in Class A. On the other hand MA-1s or MA-2s can be a bit much in small enclosed rooms in warm weather. My room is on the smaller side but is partly open to a couple of other rooms, and even driving the Sound Labs the MA-1s raise the room temperature perhaps 3 to 5 degrees.

The newer models with their self biasing are simple to use. No tube swapping needed, and average output tube life is estimated at 10,000 hours. If you accidentally short the speaker terminals with them on nothing happens, and the music resumes as soon as you correct it.

Disclaimer - I am an Atma-Sphere dealer.

[EDS_]

3. Not as great with more complex music

I don't follow, because I get wonderful results on big orchestral, rock, etc. What was your associated equipment, especially speakers, and which model did you own?

4. The pair I had were old and reliable for the six or eight months I had them

That's not very long. Why did you sell them?

Speaker impedance is a consideration at least on the S-30 and M-60, somewhat less so on the MA-1. ZERO autoformers have been used successfully in some instances, for example one customer had good results with M-60s driving Martin Logan Summits.

Yes, the amps throw off some heat, but not dramatically more than solid state amps producing a significant amount of power in Class A. On the other hand MA-1s or MA-2s can be a bit much in small enclosed rooms in warm weather. My room is on the smaller side but is partly open to a couple of other rooms, and even driving the Sound Labs the MA-1s raise the room temperature perhaps 3 to 5 degrees.

The newer models with their self biasing are simple to use. No tube swapping needed, and average output tube life is estimated at 10,000 hours. If you accidentally short the speaker terminals with them on nothing happens, and the music resumes as soon as you correct it.

Disclaimer - I am an Atma-Sphere dealer.

Hi Brian,

Sorry-I had to find some old documentation on the amps. They were M-60 Mark II.2.

I tired them with Hales Rev. III, Spendor S5e, and Triangle Antal speakers. At the time my favs. were the Hales. Clearly, the Hales presented a difficult match for the M-60s. I listen to and love everything from Slipknot to very old Heifetz.....my guess is the M-60 would jam like mad with horns or x-overless speakers.

Here in Dallas, my listening room sits on the west side of my house. Ergo the afternoon and evening sun heats my room anyway. The added heat from the M-60s was just too much. So I sold them-I must add the buyer, living in extreme south Texas, loves them.

I'd argue with you a bit about the waste heat. I have a Llano Trinity 300 (300 wpc with maybe 40wpc of that in class A). The Llano puts out far less heat. I use a Cary SLI-80 tube integrated too (2x 6922, 2x 6SN7, 4x KT-88 and 2x 5U4) the Cary might put out 25% as much heat as the M-60s did.

I'd bet someone could assemble a top notch system around Atma-Sphere amps.


Currently spinning Rainbow-"Power"

[Brian Walsh]

The heat produced is largely due to Class A operation, not whether the amps are tube or solid state. The Atma-Sphere amps operate that way throughout their power range. A Class A tube amp will put out perhaps 20% more heat than a Class A solid state amp of similar power output. For example, I own a Bedini 25/25 that puts out 25 wpc in Class A, and yes it runs pretty hot.

I would probably recommend at least MA-1s to drive Hales speakers well, which probably explains why you found the M-60s a bit lacking. Getting the right speaker-amp match is so very important.