Majestic 745 with Tube Amps

Speakers:
Sound Lab A-1 PX Bass Focus (90 degrees)
Sound Lab A-3 PX (120 degrees)
Amplifiers:
Audio Research VT-150 SE mono 130w (GE 6550 output, Telefunken E88CC input)
Audio Research Reference 160M MKII mono 150w (KT-150 output, 6H30 input)
Audio Research Reference 150SE stereo 150w (KT-150 output, 6H30 input)

All three of these amplifiers systems sound exceptional driving both pairs of the Sound Lab speakers and I find the 16 ohm and the 8 ohm outputs provide a somewhat different balance and dynamic…both output taps sound excellent.

It stands to reason why Atmosphere sells the majority of Atmosphere OTL amps and preamps to SoundLab speaker-owners

VAC (Valve Amplification Company) amplifiers also work very well with Sound Labs. I am using a Sigma 170i with Majestic 545PX speakers.

Yeah Bigtwin. Sounds like power won’t be a problem. 😎 That color in the cover is great!

@BelleMusic is right. I never imagined recorded music could sound like this. It sounds real. Jaw dropping.

Very interested in your review. particularly interested to hear how the newer panels scale.

Hello Bigtwin,

I’m driving A645 with Atma Sphere MA-1 tube mono blocs, 2 x 140W, OTL. I have also a matching Atma Sphere MP-1 preamplifier. Previously I have owned all Quad speakers and a couple of other ESL including big Stax ELS speakers.

Congratulations on your purchase of Majestics. You have just purchased a pair of the very best speakers ever made on this planet.

While many owners of SL drive these speakers with Parasound, Krell, Pass Lab and other SS amplifiers, in my humble opinion electrostatic speakers will work best with OTL tube amplifiers. The best match for your SL is actualy Atma Sphere MA-2 (which is quite expensive), but MA-1 model will work as good.

There are several technical reasons why OTL amplifires work so nicely with electrostatics but I will not enter into this subject.

To properly setup this system you will need to replace small tubes delivered with your amplifier (ans preamplifier). Old NOS tubes sound much better. Good power cords are very important. Good XLR cables are also VERY important contrarly to what says the notice, power regenerator is mandatory in all circumstances, as well as heavy room treatement. You need time and patience. Each system optimisation and upgrade will reward you with huge improvements in sound. I’m talking from my first hand experience.

Feel free to coontact me for more details.

Hi Bigtwin! Good to see you over here. Congrats on your SLs.

Couple things-

First, Roger West is pretty responsive to questions. Ususally responds to email next day. I peppered him with questions about subwoofer crossover, speaker setup in my difficult room, and more. In the process I found out Roger listens to Benchmark ABH2s. He uses two as monoblocks. Gets his highest recommendation.

Second, my SLs are preowned M1s with upgraded backplates that I got last August. My experience has been that, like the Quad63s they replaced, you need power. Both the Quads and SLs will suck dry either a McIntosh MC352 or MC2500. I use a subwoofer to handle much of the lower frequency load, trying different crossover frequencies right now. I like to listen to jazz/pop/funk 80-85 dB with tops 90 dB peaks. Classical music peaks around 80 dB tops live. So your Mahler is easier to handle.

My panels are 20 years old but in excellent shape. But they don’t have the Bass Focus feature and maybe other upgrades. So YMMV.

Will be interested in your report. FWIW, my wife, who has been agnostic about my audio purchases over the years, thanked me for buying the SLs.

You might want to also consider the Parasound JC-1 amplifiers. They’re ideal for driving these electrostatic speakers, for their power curve is the opposite of the speakers impedance curve. I drive five 945’s with five JC-1’s above actual symphonic hall listening levels.

The impedance curve of the SoundLabs range between about 3 Ohms at 20KHz, up to about 30 Ohms at 20 Hz. But acoustic music requires almost all its amplifier power below 200 Hz, and very little above 10KHz. So with the JC-1’s +/- 100V DC power supplies, the amplifier never gets out of class A operation, but delivers very satisfying listening levels of classical acoustic music.

Tom

Have you tried the Naked Zero autotransformers between your tube amps and the SLs?

<https://anticables.com/store/%E2%80%9CNaked%E2%80%9D-ZERO-Autoformers-p14644819&gt;

They help with impedance matching to transfer power more efficiently and they will enhance the SQ without adding distortion. Ralph at Atma-Sphere recommended them to me. They work great. I have even been able to drive SLs with Atma-Sphere M60s (60-watts tube mono-block amps}

@Bigwin How did the tube amp work out?

Bigtwin,
Congratulations! You will be thrilled.

My recommendation is to try them and see. Amp suitability depends on your listening volume, room size, preferred music, etc. That said 50W is not a lot when it comes to driving my Majestic skinny 745s. My AtmaSphere MA1s (140W OTL class A triode) and Benchmarks (400W Class H solid state) both drive the panels, but not to “live levels”–both run out of gas about 95 dB at the listening position.

If you decide to look for more power, PM me as my MA1s may be available.

Evan