Mixing Atma MA1s with solid state.

To really golden ears I think, SS will change the openness and delicacy of the Atma sound. I suggest you ask Ralph Karsten at Atma directly what he thinks of your suggestion.
He is a great guy and very helpful. Please let us know what you have found out. If you like, drop me a line and I'll give you his e-mail.

They will drive them. I bet Ralph will agree. I heard MA1s driving McIntosh XRT20s last week in a very large room with vaulted ceiling... incredible, powerful, lifelike sound. Go for it.

Thotdoc, if the mid-bass modules can be added with a passive crossover and the 1.7s are crossed over as well, then you have a good shot at it.

If they are simply added in parallel then you will need a set of ZEROs, which I would certainly try out anyway. They might allow more power and less distortion and won't wreck the sound of the amps (if they do it usually means you don't need them).

http://www.zeroimpedance.com

Maybe you can explain this Ralph: you make output transformerless amplifiers, obviously believing eliminating the output transformer yields great sonic benefits. Then you recommend Zeroes be placed in the signal path between amplifier and loudspeaker. What are Zeroes?

Transformers.

Sure, you can call them toroidal autoformers but the reality is that they’re outboard transformers. Rather than design them into your product—where you have complete control of their parameters—you recommend these outboard devices. Of course, this keeps the price of your product down since you don’t build the transformers in, but at the end of the day, the signal path is still transformer coupled, with all that that implies.

^^ I can explain this easily- I get this question a lot.

Actually the ZEROs are autoformers, with a very low turns ratios. They are used as problem solvers with a variety of amplifiers, not just our stuff.

One use that surprises many is that many transistor amplifiers benefit from the use of ZEROs when driving 4 ohms. This is because distortion in the amp is reduced. In high end audio, its usually about finesse rather than power.

In the case of an OTL, there are a number of cases where someone wants to use the amp with a speaker that might otherwise be a marginal or impossible combination. We used to sell our own outboard device years ago call the Z-Music transformer, but explaining why this was a good way to go became a lot easier when the ZERO came along, simply because it was not our own product!

In case there is any question, I like transformers a lot more than I like transistors. As audiophiles we are often presented with a situation where someone 'fell in love with a speaker' which might be a nice sounding speaker but not the best combination with a tube amplifier. At the same time they want to not just any tube amp but an OTL: problem solved.

BTW the effect of the ZERO is such that if the amp likes the speaker load, the ZERO will not be any help. An example is a set of M-60s on a set of Merlins. On a load where the amp is struggling (M-60 on a set of Magnaplanars for example) all of a sudden the ZEROs make a lot of sense. Due to their low turns ratio, the ZEROs actually have more bandwidth than the amps do, going from less than 3Hz to about 2MHz. This would simply not be possible with a normal OPT in a regular tube amp! The result is that the amp makes twice as much power into the 4 ohm load that it would otherwise, with lower distortion and longer tube life.

With MA-1s there is less benefit, so the ZEROs should be tried and the benefits weighed. MA-1s are much more comfortable with 4 ohm loads!