Recommended Speaker List for Atma-Sphere OTL Amplifiers.

I’m a little late to this thread sorry.

 I’ve come across some older M60 mk2 amps a friends has at his audio shop the price is right so I’m seriously looking at them. Question is will they drive high efficiency horns like the current klipsch heritage line. I’ve currently been trying  some modded heresy 3s with the thought to move to the new Heresy 4, Cornwall 4. Or La Scala in the near future. 
I’m very new too OTL Amps but am quite versed in SET etc. I’m coming from SET 300b Amp. So tubes are not new just OTL. 
Also I read the amps can be run with less tubes at lower power is this correct? 
I am considering a trip to the shop for and update-recap-etc as required.  Probably new tubes as well as the ones in it are unknowns and miss matched. I suspect the previous owner pulled his good tubes when he traded it. 
Thanks I’m advance 

glen 

thanks guys for answering in this older thread. 

luisma31 thank you for the tube quantity information. 

I believe the M60 Mk2’s i’m looking at have the mk3 upgrade already if not I’ll send them to Atmos for the upgrade. 

AudioTroy thanks for that quick comparison that makes sense to me after owning the Finale Audios 300b’s great amps, but they never left me with the feeling they were doing the speakers justice I had at the time (living voice speakers only 94db, I've since been experimenting with horns). 

I've owned and enjoyed a few ProAc models over the years as well so nice to know they are a good match. (older ones anyway). 

thanks all I've texted my friend and going ahead with the buy. consider me M60's owner. 

Now to decide if to keep my preamp or move to a balanced Pre. I have a completely redon Sansui CA 2000 that has every cap -diode - and various other things replaced. Its surprisingly good sounding now.  Its actually down right amazing now, with so much flexibility I forgot how much I missed some of the things old preamps had). 

But a simple Schiit Freya + may satisfy the balanced proposition on the short term as a reasonable cost alternative. I also have a balanced Schiit multi bit DAC Gumbi and Gold Note PH10 phono stage that's also balanced that may move me to a whole balanced system, well mostly my tuner isn't balanced. 


Cheers all

Glen

I’ve bought the M60s. It’s a rather different step then I was originally going to go but the opportunity to have some truly excellent amps was hard to pass by. I’m not a rich man being a retired military career man. I had originally got out of 300b amps they just didn’t do it for me that little power. I was going to play with vintage for a bit until I decided where I was going. The Atmos amps sort of fell into my lap so it’s changed my path somewhat.  
I only brought up the Freya as I thought it was a fully balanced peramp that could be a starting point. But I do have a totally rebuilt vintage Sansui CA 2000 I was planing for a vintage set up that’s actually quite good sounding but only single ended.

Obviously it’s a vintage preamp and not to the level of Ralph’s own preamps. But after spending money I didn’t really have on amps I’m not in a position right now to buy a preamp until I sell off the vintage gear I have. And let’s be honest my speakers are not going to show what they are capable of anyway at this point until I upgrade. 
Thanks for the advice my friends. Looks like my audio journey has taken a turn for the better.  I’ll be picking up the amps in a week or two once my friend reopens his shop.  Closed for cov19 at the moment.  From there I’ll buy a new tube set as they are questionable and mismatched brands. Actually any recommendations for tubes for that work well in the Atmos OTL would be helpful. 
Ralph thanks for the support. I believe these amps were sent to you in 2015 for the mark 3 update. I’ll check once I get them and if not arrange to have them sent to you. I can see one amps serial number in my picture it’s 236 I can’t make out the other amps. 
Exciting times in audio. 
Cheers my friends 

Glen  Newdick 

atmosphere:  
Thanks Ralph I'll take a look in a week when I pick them up. If there is upgrades to be had I'll send them to you. Looks from the paperwork he gave me they were updated to 3.2 status in 2012. but there is some paperwork form 2015 as well.

 I figure best to confirm with you off this thread. I'll write you in your company email when I get the amps in house. Just a side note one of the reason's I bought them is because of your continued support in the audio world and to us the customers (even buying used) its rather nice to see in this day and age. Thank you. 

luisma31 I think I may have 3 NOS RCA red base 6SN7's so maybe I can source a few more. I may have a source locally. I used them In my Finale Audio F 3008 300b integrated.I sold that few months ago so have a few tubes left over. Now I wish I had the Living Voice Avatar 2's I sold at the same time, I bet they would have been wonderful on the OLT's. 

 yes there is shorting plugs with the amps so good to go there for single ended. 


I'll probably get some Russian power tubes for it, But I'll have the ones in it checked (on a tube tester) first as they are all the same brand, just the drivers are mismatched.  

Thanks friends for all the advice and input, be safe out there and lets all get though to the other side of this Cov19. 

See how one pleasantly unexpected perches can derail your whole audio plan. 

cheers 

Glen 

Got my M60’s yesterday and found them to be updated to 3.2 status. Thanks again everyone for the help. 
So now I’m quite happy with the sound as I said first thought was; clear from top to bottom and the base is so much better then the 300b amp I had prior. Time for some hours and fun listening 


cheers everyone