Zero Autoformer good/bad for Atma/Quad combo

If I had to use Autotransformers with the Atmasphere, I think I would rather use a regular tube amp that has transformers built in. Defeating the purpose.

different kind of transformer... Does not defeat the purpose of a OTL. But, having said that, it is adding something else to the chain.

No, I would not expect any benefit from using Zeros with MA-1s driving 988s. M-60s might be a different story, but I would try them with and without.

M-60s drive Quad ESLs (57s) quite well without need for Zeros.

Jwm, just for the record, all ESLs have an input matching transformer. So if you used a set of ZEROs with a transformer coupled amp you would be passing the signal through three transformers if you were using ZEROs.

Even though we are an OTL manufacturer, (IOW if I say so myself) the use of the ZEROs **does not** defeat the purpose of the amps! A transformer like the ZERO would not even be possible if you did not also start with an amplifier that already has a low output impedance, since the ZERO loads the amps at 16 ohms.

Because of the very low turns ratio, the bandwidth of the autoformer is from 2Hz to about 2MHz- wider than almost any amplifier made. Even transistor amplifier manufacturers report that their amps sound better driving 4 ohms through the ZEROs rather than direct. The lesson here seems to be that while a transistor amplifier might double its power while driving 4 ohms, that is not the same as saying it sounds its best while doing so.

The same is true of tube amplifiers- the ZEROs can be regarded as a problem solver or assistance to any amplifier that has to drive a low impedance (so long as that amplifier does not make power too excessive for the ZEROs). So, it would be one thing if only OTLs benefit from ZEROs, but when **all** amplifiers do, its hard to say that they defeat a purpose :)

In the case of the MA-1s, they are a big enough OTL that it is hard to say if the ZEROs will help. Certainly with M-60s they do- the later Quads tend to have a generally lower impedance curve than the earlier 57s and 63s (which don't seem to need the ZEROs).

Have a Happy New Year!

Thanks for the input Ralph and everyone else!

So, I auditioned a set of Zero's (at home) and honestly I did not hear a beneficial difference in my system. Now, I'm NOT saying the Zero's aren't beneficial, there are definitely impressive experiences out there. I just did not find them helpful in MY specific system.

I tried the 2X, 3X, and 4X taps, tried running them over night, tried one speaker with / one without during mono playback... And what I heard was;

the 2X tap is VERY close to without. It does smooth out horns and dynamics -- not to my liking though. I feel like something "real" has been taken away and replaced with something "hifi". The dynamics began to sound slightly compressed, loosing the "punch" of say - drums. Horns were more sweat, some of that brassiness was lost.

The 3X tap moves voices forward on stage a bit. But, again, increased the dynamic smoothing described above.

The 4X tap brings voices forward more. But more-so flattens out liveliness.

Thus, for my liking, I couldn't see keeping them. Appears my system must be matching up well, I do have the MA-2 Power Caps installed in my MA-1's -- I don't know if that makes a difference, but nonetheless, I reckon I'm not experiencing any impedance problems...

On a side note, I say that Paul, at Zero Impedance, was the best -- he got the Zero's out to me fast, offered fast assistance / advice, did not question their return, and was fast reimbursing me. Absolutely great experience, even though the Zero didn't work for me. Thanks Paul (if you ever read this). --So, for anyone else considering the Zero's, trying them out is pleasurable to do.