Atma-Sphere M60 or David Berning ZH270?

For those who haven't kept up with everything, Ralph has ALWAYS favored the old chassis of the M60. It's his seminal design, it is HIS amplifier (in any and every way you can think of). If you put a gun to his head and told him he could only make one product, this would be it. As a picture is worth a thousand words, you can see that he has returned to what he believes in. We should ALL be ecstatic about that.

John (Sutts) and I almost always agree, as we do here. So, a classic tube amp seems to be the way to go with the Coincidents. I will say that a good friend of mine ended up with the Coincident Triumph UHS because they were one of only a couple of speakers that we found that could be driven with his absolute flea powered AudioValve integrated - supposedly 25 watts, but it sounds like 3 wpc to me.

Laoyuap, yes, my Coincidents are modded. The mods are quite extensive.

The original Vifa tweeters were replaced by ScanSpeak Revelators that I got from Israel. The Seas midwoofers were completely rebuilt by the BEST speaker guy in the world - this mod is more significant than I can explain to you. Let's just say that naturalness, speed, and slam all jumped up several steps. The wiring was replaced. The cabinets were damped, but not overdamped, and stuffed. What was a very nice speaker came to realize its full potential.

And, OTL amps have always been rare. If Coincident wanted to keep going in that direction, nothing would have stopped them.

As our very dear friend Michael (Swampwalker), has owned the Berning ZH270, AtmaSphere M60, AND a Joule Electra, he is the authority here. From his experiences and perspectives, which I trust a great deal, the Atmas are a bit warmer and richer than the Bernings. This would suggest a better marriage with the Coincidents...

But, as Spencer pointed out, with my Coincidents, which are incidentally warmer and more full bodied than any other pair you will find out there, the OTL sound does not seem to suit them as well. Not that the sound is bad, but it is does have a bit of harshness and brightness that I was never able to get rid of with my MKII.2. The MKII.3, plus a lot of upgrades instills the liquidity that I need into the sound.

Still, after the holidays with my Granite monoblocks, and ESPECIALLY this past weekend with my Jadis, I am more or less convinced that the Coincidents sound best with a transformer coupled tube amplifier. I know that the rumor is that Israel Blume has used the M60s to voice his speakers (and a call to him will show he knows A LOT about the amps), when he released his own line of tube amps, they were transformer coupled SET 300B based. And, at CES, for the past several years, he has partnered with EveAnna Manley, to rave review.

In my experience, an OTL amp seems to mesh better with a more relaxed speaker, such as Spencer's Merlins. That Dynaudio Esotar is a much smoother tweeter than the ScanSpeak Revelator used in many of the Coincidents. This is not to say which tweeter is better or worse, as both have their legions of devoted followers.

And, for whatever reason, as Spencer said, my specially modified pair of Frieds (they were Bud's own pair up until we got him a new pair of Studio VIIs this fall), seem to just make really good sound with the AtmaSphere M60s. I think it's the "resistive load" loudspeaker that meshes so well with the OTL (remember, Ralph owned Frieds for so many years).

For what it's worth, I am not a fan of running less tubes in the Atmas. Yes, you'll throw off less heat. Yes, you'll use less electricity. Yes, this. Yes, that. But, if you are really concerned about these issues, I would say that the sonics of the two amps are probably similar enough to say that the Berning would be the obvious choice.