Thought on OTL tube amps

Sorry to say that the atmas are not stand alone OTL tube amp but need output transformer  plain and simple.

realdeal- You are incorrect.  Many, many people use Atma OTLs direct to speakers that have the appropriate impedance characteristics, including myself, and they sound terrific.  Have you ever heard any of Ralph's amps driving the appropriate speakers? 

realdeal, you are truly misinformed. I have run three different levels of the glorious Atma-Sphere OTL amplifiers S-30, M-60, MA-1 Silver on numerous loudspeakers with no issue whatsoever! All were played without autoformers, all were played through 8-16 ohm nominal impedance loads. It is abundantly clear that you have no proper, real life experience with these amplifiers. You really should do yourself (and the rest of us) a favor, and go out and get a good solid audition of these babies and then come back with an honest opinion.

Happy Listening!

The Zero autotransformer will not make  amplifier output impedance and the speaker input impedance higher as  Paul Speltz claim,It only decreases impedance on both input and output but it increase output  power due to less impedance and more current.There's a lot of Paul explanation about the Zero  are wrong.

Realdeal, as I indicated in my response to the very similar comment that was made by Xonex77, that is simply not correct. A suitably designed autoformer can transform voltages and impedances no differently than a two-winding transformer can. Although there are obviously other differences between the capabilities of the two kinds of devices, most notably the obvious fact that an autoformer can’t provide electrical isolation.

You (and Xonex77) may want to read up on autoformers a bit more. You might also want to reflect upon the various McIntosh solid state amplifiers which use autoformers at their outputs. Which by presenting the output stages with the same load impedance when a 2 ohm speaker is connected to the 2 ohm tap as when a 4 ohm speaker is connected to the 4 ohm tap as when an 8 ohm speaker is connected to the 8 ohm tap, enable those amplifiers to have identical power ratings into 2, 4, and 8 ohms.

Regards,
-- Al