[RGordonpf]

http://www.zeroimpedance.com/products.html


The above product raises the impedance your amp(s) see by a factor of 2X, 3X or 4X.  For those of us driving our VMPS speakers with OTL or SET amps the opportunity to raise the impedance is attractive.  The website lists VMPS as one of the speakers that customers have used with the Zero-autoformers.  Does anyone on this forum have first hand experience with either the Zero-autoformers or the Z-Transformers that Atma-Sphere used to sell with their OTL amps?

I am curious as to the whether the drawbacks of adding additional iron to the signal path is secondary to the benefits gained by having the amps see a higher impedance.

Thanks for any experiences that you can relate.

[jaxdr]

I am in the process of purchasing an Atmasphere MA1 MK3.1 and will trial a autoformer with my RM40's. I will let you know my comments. I have heard one positive comment on a RM40 with the autoformer. Did you gain any further information on VMPS with the autoformer.

[warnerwh]

Back in the 70s I listened to a Mac and a Phase Linear 400 amp through the same system at an audio store. The sound from the Mac in the highs seemed subdued or the Phase Linear had a slightly tipped up high end. The sales guy said the reason for the sound of the Mac was because it had autoformers. Whether that is true or not I don't know.

The difference was very obvious between the two amps to the point that anyone could tell in a double blind test 100% of the time. My friend liked the Phase Linear better and bought it. I liked the Mac better myself. The idea of using autoformers though I think is a good one in some cases like yours. I don't know if Mac still uses them or not.

If you want to know more about autoformers email this guy:  http://www.roger-russell.com/
He was an engineer for McIntosh and can tell you about autoformers.

[John Casler]

How interesting;

The OP wrote his post in July of 2007.

The first response was Dec 30 2011!!!!

Roger, you still out there?   

I hope to see you in VEGAS.

[zybar]

http://www.zeroimpedance.com/products.html


The above product raises the impedance your amp(s) see by a factor of 2X, 3X or 4X.  For those of us driving our VMPS speakers with OTL or SET amps the opportunity to raise the impedance is attractive.  The website lists VMPS as one of the speakers that customers have used with the Zero-autoformers.  Does anyone on this forum have first hand experience with either the Zero-autoformers or the Z-Transformers that Atma-Sphere used to sell with their OTL amps?

I am curious as to the whether the drawbacks of adding additional iron to the signal path is secondary to the benefits gained by having the amps see a higher impedance.

Thanks for any experiences that you can relate.

No experience with the Zero/Atma-Sphere MA-1 MK 3.1 combo with RM40's, but I use them with my Vandersteen 5A's and have heard them on Wilson Sashas, Omega Revolutions, and Emerald Physics CS2's as well.

In the case of the 5A's and Sasha's there was a clear improvement in not only the lower octaves (bass was "faster", as well as more articulate and defined), but the midrange and highs also improved.  The midrange was clearer and more open sounding, while the highs were a little more extended and airy.

While the Zero/Atma-Sphere combo has worked its magic with the 5A's and Sasha's, it won't necessarily work for every speaker.  When I tried Zeros and Atma-Sphere M-60 MK 3's on Omega Revolutions (single driver Alnico based speakers) and Emerald Physics CS-2's (open baffle), not only wasn't there the substantial improvement that I hear with the 5A's and Sashas, I could hear a slight haze or dulling of the music.  Could be that each of those speakers presented such an easy load for the amps that there wasn't a benefit.   

I think that Paul (Speltz) offers a trial period, so you can judge for yourself.  I am glad I gave them a try and once inserted into my system, they haven't come out.

George
While the Zero