Recommended Speaker List for Atma-Sphere OTL Amplifiers.


OK, I am not sure how many times this has been disscused but the information is found all over the forum. I would possible love to compile a list here.

I personally own the Classic Audio Loudspeakers T1.5

I am now looking to build a second room with the M60 Mono Blocks and MP-3 Pre-amp.


Would love fellow audiogon memebers posting any feedback with speakers they have used with these Amazing OTL sounding Amplifiers.
dragon_vibe

Showing 9 responses by luisma31

I believe you should have no problems running the M60s with the Klipsch line, if you are coming from the SET world where typically you manage less power than what this OTL can offer you should be fine. Yes you could run the amp removing tubes but I personally wouldn't, others have said and I have my subjective feeling and like many other cases that running with full capabilities will provide better sound at lower volumes with high efficient speakers than with same settings and tubes removed. I have MA-1s BTW and I run all 28 tubes all the time with high efficient speakers, the power tubes in the Atmas are very inexpensive and they last a long time because the way their circuit operates, the mk3 revision improves this as well if I'm not mistaken so it might be worth sending the amps to Ralph if you have the financial means of course to check them and reactivate the warranty and upgrade.

Which preamp are you planning on using?
How big is your room and how loud you listen to music?


I personally was thinking mainly on impedance more than in sensitivity terms, you are correct impedance is big part of it, most of klipsch is usually 8 ohm nominal and above 93 sensitivity, I have P37f as secondary speakers and very easy to drive with the Atmas, mains are AudioKinesis which are 95 dB and 10 ohms.Anyway, could you recommend me an amp like bourbon? Not much into chocolate milk.
Joking aside, the preamp used could have a lot to do with your SET comparison but I have to ask which type 300b?

Thank you, I asked because I can't comment on the 300B SET as I haven't had a chance to compare one on my system, I have a PSET in which I tried many different tubes combinations (not 300B) and when it starts clipping and distorting is not very pleasant, still better than a SS but obviously distorted. The Atmas on the other hand (and this is not apples to apples as I have MA-1s) are wonderful driving 10 ohm speakers.
If you are listening to low volume the PSET is pretty good.
Keep in mind the m60 have 8 power tubes vs 14 on the ma1 so you are accounting for 60 percent or so of the ma1 power, which is IMO sufficient
Ask Ralph Karsten of atmasphere about your speakers, pre etc he is very helpful even on used equipment, my opinion is irrelevant here, if you like to listen to music at high volume the m60 might not be enough
it doesn’t support the balanced standard
Hi Ralph, good to see you chimed in.
Just for education purposes when you say it doesn’t support the standard do you mean "it is not differential", aka duplicate stages + and -?Hope you are doing well


I’m sure you will enjoy the amps Glen, I believe you could use the Sansui with no issues except you will need to short pins 1 & 3 per the Atma manual (see below)
"If you use the RCA input connector, make sure a shorting jumper is installed between pins 1 & 3 on the XLR connector else a buzz may result"
The most important tubes for the sound are the driver tubes the 6SN7’s, I know you are not buying stock but the stock tubes that comes with the Atmas out of the box usually chinese Shuguang Brown Base 6SN7s are very decent, that said you could improve with NOS tubes or even some Chinese Boutique tubes, if you need more on the subject I can provide more details and I’m sure others will do as well.The power tubes "sonically" won’t provide much, not many options either, the Russian 6AS7G Svetlana’s 6H13C are very very stable, sound is magnificent and to me these are the tubes to go on this amps as far as power tubes is concerned. The NOS RCA’s 6AS7G could provide a little more power at the expense of reliability and headaches, and money too. I went that route and turned back, my MA-1’s do fine with the power offered by the Russian power tube the way Ralph designed it. If you need more details I will be happy to provide such but my advise if your speakers do fine with the Russian tubes don’t change them, I experience one of the RCA tubes heavy arcing, smoke came out of the amp (or tube) and it is very common with these tubes, IMO reliability is an issue. DO NOT USE 6AS7GA on that amp, the tube IS NOT COMPATIBLE, stay away from GE’s 6AS7G, you will run into problems.Let us know what tubes comes with the amp and I’m sure Ralph or someone else or myself will be able to help.Maybe I missed it but your speakers are sensitivity? and nominal impedance?
Actually I’m confused by @glennewdick comment, the mismatched tubes could be driver tubes which as long as it complies with atmasphere recommended any 6sn7 except for the single position (which should be GTA or GTB not GT) would be fine

Power tubes should be all the same