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

Oh, one issue I forgot to address are the chassis of the M60 MKII.3.

There are currently THREE different chassis available.

The old style, with the tubes in the front, transformers in the back, and the squared off transformer covers. This is the classic M60 design.

The "other regime" style, with the transformers running longitudinally down the middle of the amps, with tubes on either side. It looks like the S30 and MA1. I believe Ralph is not a fan of this design and it will be going by the wayside.

The third style is the Rendition, which returns to the classic M60 layout, updated with rounded transformer covers and a stainless steel plate in front of them. It's a takeoff on the original design.

To my eyes, the Rendition looks like the 1940's (streamlined - aerodynamic), whereas the other design looks like 1950s (modernist - contemporary). I like them both. Which do I prefer? I don't know, I keep going back and forth...

While 4 ohm speakers are not kind to the M60s, a lot of people use Reimers with low powered and SET tube amplifiers. I would at least try it. And, regarding the Zeroes, Ralph knows I find they detract from the sound (you lose the AtmaSphere magic). Atma means "soul", and I guess I would just call them Spheres at that point. Still, a lot of people are fans, so you might want to give them a try and see where you stand.

The Atma-Sphere M60 can be ordered in any of the three styles Trelja describes. The Rendition Audio M60 looks pretty much the same, one exception being the meter which functions as a VU meter on the Rendition.
Brian

Trelja, your NOS 12SX7's that you bought, are you talking about USA or EU brands, or Chinese, Russian, or Yugo brands? I'm not sure, since you say that the 12SX7's are not being produced, so all tubes would technically be considered NOS. What are the sonic advantages of the 12SX7's over the 6SN7's? I just sent my M-60 Mk. 2.2's back for circuitry upgrades (but no A/B mode for me, thank you very much!) Hopefully, you are also using an Atma-sphere pre-amp, as well. And what are you using for speakers?

711smilin, I agree with Trelja. You will be buying a great product, while helping people who are definitely in need and badly hurting. I didn't mean to sound callous concerning my comment about a charitable tax deduction; I just didn't want you to get a big surprise from your "Uncle Sammy"!

Fatparrot, the tubes I picked up last week were just about all grey glass RCA 12SX7 tubes. I think that two of them were General Electric as well.

By the way, my favorites so far are a pair of RVC (RCA Canada) grey glass I picked up in the fall. They have the RCA 6SN7 grey glass kind of sound, which is a really fat midbass, lending some welcome (for me) warmth to the sound, in addition to a whole lot of slam. I use them in position V1, which is where I like them best.

It is kind of hard for me to describe their superiority over 6SN7, as the amps that I have that use them came that way. I was never able to listen to them with the 6SN7 tubes. It is a unique pair, and probably one of the finest sets of M60s in existence. They're certainly superior to my former pair, which needed the power supply upgrade as a start.

I will say that the sound of this pair is extremely liquid, relaxed, and natural sounding. Yet, at the same time revealing of astonishing detail, with a good bit more powerf in the bass. This particular pair has a lot of advantages over my former amps - better passive parts (teflon film/foil caps, etc.), a big bump in the power supply, and no negative feedback. There are a few other things with this pair of amps, such as test jacks on each output tube to measure it, the B+ supply has been modified with voltage regulation(I have no idea...) and a "pi filter" has been added to the driver stage power supply. Basically, they were sent in with the mandate to do every possible upgrade known, and that was that.

From other people who are more familiar with the before and after of the 6SN7/12SX7 with their pair of M60s, they are considered a super low distortion tube. I have heard that they take a lot of the best traits of the RCA (big time bass) and the Sylvania (superb midrange and treble) and put them into one tube. Hopefully, someone who has done the surgery can chime in with their opinions here, as I am beginning to drive past my headlights in this post. It's probably also time for Ralph to put me in my place...

Fatparrot writes:

711smilin, call Atma-sphere (Ralph or Bill) since they will be able to best help you with your decision. And forget about the tax write-off, which only comes into play for an amount OVER the fair market value of a charity item!

Thanks for the clarification on the tax issue.

Regards,