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Atma-sphere M60 II.3-Any good for 4 ohm speaker?

Guys, I like the idea of trying OTL, but, in looking at the mfg. web page, I see the power rating going down to 40 watts for 4 ohm load, and going up to 80 watts for 16 ohm load. I am receiving my speakers next week, and they are 95DB with a 3.8-4 ohm load(Reimer Tetons)What do you think of these amps with a 4 ohm speaker. Also, why does the power go down, not up?

Thanks in advance
711smilin
jwin's avatar
jwin
101 posts
 
Does anyone have any experience with MA-1 11.3 and Dunlavy SC-4a speakers? They are also 4 ohms, 91db and pretty stable.
Jeff
rushton's avatar
rushton
2,430 posts
 
Jwin, I've not heard this combination, but they might work depending on the minimum impedance, how smooth the impedance curve is, and the characteristics of the bass driver. Adding a "Zero" autoformer might be useful. The best answer would come from Atma-Sphere. If you call or email Ralph, he can tell you if he has customers using this combination successfully.

What I can say is that the Atma-Sphere MA-1 Mk.II is a stunning amplifier in its neutrality, transparency, speed and (with complementary speakers) tremendous bass control and impact. This is coupled with exceptionally truthful rendering of harmonic overtones and an overall musicality that is instantly addictive. Good Luck!
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jwin's avatar
jwin
101 posts
 
Thanks Rushton. The impedance of the Dunlays is pretty flat. It ranges from 3 ohms to 7.5 ohms max. Wouldn't a zero autoformer put a transformer in the circuit of the OTL design?
Jeff
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