Zero Feedback: Atmasphere vs. BAT

It's a tough choice. I think if I want Atmasphere amps I will sell my Spendor's which I really like for their natural sound. I would look for something that could run on the M30, I thought that AudioKinesis Jazz Modules looked good with an M30.

I think with my S8e's I could enjoy BAT VK75 and then try a second and run Mono down the road if more power is required.

The question is should I sell and go with horns and low power class A? Should I keep what I have and go with something like the VK75? "Gold Plated Decibels", maybe that is what keeps the common man from having a world class system. Bottom line you may need effecient speakers to have the best gear feeding them at a reasonable cost.

That's where I am at today. Been listening to Spinnerette, Ghetto Love to distract me as I think about system re-design.

Thanks for your input.
Scott

Scott- Both of those amps are balanced. Are we correct in assumming you have a true balanced output pre-amp? I had a BAT pre-amp a few years ago and then a pair of M-60s. (BTW, its an s-30 stereo amp @ 30 wpc or an M-60 monoblock pair at 60 wpc). Both are quality products w excellent support; I would say that Atma is next step up from excellent, whatever that is. If you send a used product back to them for a check-up they will re-warranty it. Ralph was also very helpful when I was considering sending a used R to R tape deck to him for refurbishing. He actually advised me that the cost of having him do the work would greatly exceed the potential return. The Atma amps are pure class A and IMO do heat up a room, but so will a pair of the VK-75s w those huge output tubes. I've had a Joule VZN-80 that has the same complement of output tubes as the BATs, I'm pretty sure. They both get HOT!!! FWIW, Duke @ Audiokinesis also offers outstanding support. He sells Atma amps among others. Based on his contributions to this site, I would expect him to give you a very honest assessment of the differences between those two amps driving his speakers.

The BAT topology is not exactly push-pull, but rather single-ended floating bridge(similar to Atma-Sphere), as described by Victor Khomenko:

"The VK60 is neither a traditional single-ended design nor a push-pull design. We refer to the VK-60 through VK-1000 amplifiers as single-ended bridge designs. This fundamental circuit dates back to the early 1950's and was invented by Henry Wiggins while working for the ElectroVoice Company. The original name for this type of output topology was Circlotron. The single-ended bridge design relies upon two single-ended amplifiers arranged in a floating bridge formation. This differentiates it from other forms of bridge topologies, most of which effectively incorporate two push-pull sides. The output circuit is inherently balanced and is driven differentially from a preceding stage. The two DC bias currents that exist in each half of the output stage cancel each other in the load. It is a more expensive way of building an amplifier as it requires multiple floating power supplies, as opposed to the more traditional ground-referenced supplies. The benefits of this approach, however, include enhanced symmetry when compared to push-pull designs and lack of the DC saturation problem inherent to single-ended designs."

After hearing an Atma MA-1 I was ready to sell my VK-75SE, but instead set about modding the piece to the point that I feel I'm getting similar performance. Both manufacturers provide excellent customer service, with Ralph at Atma going the extra mile regarding customization, upgrades, and long-term personal relationships with customers.

You can't go wrong with either of these similar designs. However Atma OTLs need to be closely matched to speakers with benign impedances, and they do run hotter.

Atma-Sphere's RK has been very public here on Audiogon about his conviction that feedback is a no-no in amplification.

Hi Dgarretson,

Thanks for the message confirming that if you want an Atmasphere amp, start with that choice and then roll forward. If I go Atma, it would be an S30 and then find some speakers that can go with it. I was thinking of DIY speakers to try and get world class sound on a budget.

I checked out your system, I am blown away by your engineering of basic components into something totally unique. Amazing.

Cheers!
Scott