July 2019

Sanders Sound Systems Magtech Stereo Amplifier
Clear, clean presence that sounds alive and breathing.
Review By Ron Nagle

  What follows must be a story of evolution. And in a broad sense It will serve to illustrate some of the technical advances that have been made to bring music into our lives. Driven by our need to experience music we keep technology in a constant state of flux. Ever reaching for an elusive totally immersive experience. Back in May 2008 within the pages of Enjoy the Music.com I wrote about the original Sanders ESL Audio Amplifier. It was made to drive impossible electrostatic speaker impedance variations. And more specifically it was intended to power the designer Roger Sanders own Innersound Electrostatic speakers. At that time, eleven years ago, I owned and enjoyed a pair of Quad 63 Electrostatic speakers mounted on eighteen inch high Gradient woofers. And subsequently I purchased that Sanders ESL amplifier to power my Quad and Gradient speakers.

Back Story
Roger Sanders is an interesting story unto himself. Back in 1974 he authored an article in Speaker Builder magazine about electrostatic speakers. And then in 1976 this was followed with an article on amplifiers designed to drive them. In 1980 he wrote about the construction of an electrostatic speaker with a curved diaphragm and he was the first to develop this curved profile. You might remember that a similar Curvilinear electrostatic radiating surface is the hallmark of the loudspeakers made by the Martin Logan Company. He is best known for his contribution to the state of the art in his book, The Electrostatic Loudspeakers Design Cookbook published by the magazine The Audio Amateur in 1993.

In 1997 Roger Sanders joined Raj Varma to form the Innersound Company. Their products were a hybrid loudspeaker with a cone woofer and a flat electrostatic panel and the Innersound ESL amplifier designed to drive their loudspeakers. Both products received a lot of good press in the audiophile articles written at that time.

In 2003 the Innersound Company moved from Georgia to Boulder, Colorado. In 2004 Roger Sanders left Innersound and in 2007 he formed Sanders sound Systems now located in Conifer, CO. It is important to note that Mr. Sanders has managed to continue to make and improve his ESL amplifiers and he has resumed production of his innovative electrostatic loudspeakers. With the new Sanders sound systems Model 10 loudspeakers he abandoned the curved electrostatic panels that he developed. Explaining that the curved surface introduces a new set of problems not inherent with flat electrostatic panels.

The Years 2008 And 2019
Fast forward, to a time eleven years after I reviewed and then subsequently purchased that original Sanders ESL amplifier. Back then my reasoning was simple, it produced a bullet proof 360 watts per channel and was capable of driving less than one Ohm loads. Therefore, it would drive any speakers that might come my way. The cherry on top was that it came with what was for all practical purposes is a lifetime warranty and against manufacturers defects. Fast forward to the present time, that was when old man curiosity grabbed hold of me. The exact date and place was April 16, 2019. On that date I was covering the AXPONA show in Chicago and I stopped In room 1492. Roger Sanders was demonstrating his $17,000 Model 10 Electrostatic speakers with his $4500 Preamplifier and his $5500 Magtech Stereo Amplifier and a pair of $17,000 Magtech Monoblock amplifiers along with his new LMS, Loudspeaker Correction System. This was most certainly one of the better audio demonstrations at the show.

I sat down to take a photo and for a brief listen. Then I started a conversation with Mr. Sanders. I commented that some years ago I had reviewed and purchased an earlier version of his ESL amplifier. The conversation shifted to all the advances and the improvements he made with the redesign of the current Sanders Magtech power amplifier. Roger Sanders explains that the new Magtech Amplifier is physically the same size as the original ESL amplifier. It measures 17" wide, 5.5" high and 14" front to back and it weighs in at the same 54 pounds. Without getting into deep technical stuff Mr. Sanders mentioned that much of the work centered about designing a new very innovative linear Voltage Regulator.

This new regulator is 99% efficient and is stable regardless of the amplifier load and the line voltage. It is the only amplifier on the market using a linear Voltage Regulator in the power supply for that purpose. The Magtech is claimed to be the only transistor high power audiophile-grade amplifier on the market that is fully regulated. Biasing and stabilizing any amplifiers output transistors had perennially been a problem due to heat causing thermal drift.

Motorola solved this problem just a few years ago with their invention of the "Thermal Trak" transistor. This device contains a thermal sensor inside the transistor itself. So it immediately senses and "tracks" the temperature of the transistor. This makes it possible to immediately provide feedback to the amplifier's bias control circuitry so that the bias automatically adjusts itself virtually instantly. As a result, amplifiers that use Thermal Trak transistors have vastly more stable bias than conventional designs that do not use Thermal Trak transistors. Now the Magtech amplifier is so stable that no matter how the load on the speaker might vary the biasing of the output devices remains rock solid and constant.

The Magtech amplifier with additional output transistors now produces 500 Watts into 8 Ohms and 900 Watts into 4 Ohm's. As I read through the Magtech list of specifications I found they were simply everything that I could want in an amplifier. In this audio thing that we do, can we truly ever find the end of the rainbow? There is always something up ahead, an elusive best. And so hat in hand I inquired of Roger Sanders if he could/would upgrade my old original ESL power amplifier, and he graciously agreed.

Genesis
The original Rogers ESL amplifier had no detectable faults. I ran it for eleven years on a day by day basis up against any and all comers. It was a workhorse at the heart of my reference system. It served as a lab standard, comparing it to tube and solid-state amplifiers and speakers of every imaginable design. All of that time it was completely transparent, quiet and reliable. As is my habit even before I sent the ESL amplifier back to be upgraded. I looked up some on line audio chat rooms. No one had any negative things to say about the original ESL amplifier. And I could not find any negative comments about the Magtech amplifier. But, One or two of those on line audio guys said that they believed the amplifier needed 50 or 100 hours to perform at its best, we shall see!

When the upgraded ESL amplifier now the Magtech amplifier was returned and it was still stone cold and right out of the box. The sound was a transformation and a revelation. Not only did it sound like a completely different amplifier I don't remember hearing any solid-state amplifier that was so effortlessly clean and dynamic. I was getting tight controlled bass even from Pandora Blu-ray and from CD recordings I played a hundred times before. But never was there bass delineated and defined like this.

Understand I'm not at all concerned with how deep a bass frequency can go. My definition of bass rests on the ability of any amplifier to portray the smallest micro-dynamics and the most subtle timbral shadings even down to the lowest registers of music. That very quality is contained on my reference, a recording of Harmon Lewis and Gary Carr's duet performance of Adagio d' Albinoni. This is a recording of a large Pipe Organ and a bowed Bass Fiddle performed in a large stone walled cathedral. There are passages in this performances containing very deep sustained bass organ peddle notes that seem powerful enough to move and energize the stone walls.

The organ pipes echoing reverberation in this cavernous space seems to reinforce the timber of the reverberating wooden body of Gary Carr's Bowed Bass. At times his bowing produces a low moaning sound. That seems to cry out mournful feelings of pain and despair. At this point only a stone cold heart could ignore that deep quavering cry. For one split second, there is a pause in a repeating bass chord that mimics a heartbeat.

I can hear Harmon Lewis foot pause as he transitions to one of the organs foot pedals. In all the years I listened to this performance I never knew why there was a slight pause at that moment, but now I understand. I hate to fall-back on a tired old phrase. But small details emerged out of a very, "dark black background." Translation: A condition whereas the musical passages overlaid a clean clear field free of any extraneous electronic artifacts. In fact the performance was now capable of revealing subtle vocal details that had been buried in the performance. Also even at moderate listening levels I was impressed by new and unexpected dynamic contrasts a flowing tension/release that gave the performance a sense of life.

If I wanted to convey a living breathing presence than I can think of nothing better than a cut from a wonderful Clarity Cable Demo disc. First track on this CD is a really great recording of Peggy Lee singing what I believe is her signature song, Fever. It starts with a deep drum whack, following this is a resonant plucked bass fiddle line with a natural wooden resonance that imparts a structural architectural solidity to the bottom end. This acoustic bass line sets the tempo throughout the piece and supports Peggy's vocal phrasing. The bass reproduction is exactly as it should be warm wooden and organic, nothing added nothing lost. Those very same natural breath of life qualities place Peggy Lee about eight feet in front of me. The image is a clear clean presence seemingly alive and breathing.

Vinyl
Transitioning now to one of my reference vinyl recordings, it is Christopher Cross, the album is called, Another Page. A wonderfully made vinyl disc encompassing an all star cast. With backup vocals by Art Garfunkel, Don Henley, Karla Bonoff, Carl Wilson and Michael McDonald. The lead performance on side two is the track, All Right. Within a segment of the backing vocals you can clearly hear Michael McDonald voice deep in the background repeat the phrase, It's "All Right." Once again here is a music "passage I listened to many times before but never with the backup vocals carved in relief with such timbral resolution and clarity. If I were asked what single thing stands out and turns good into great it would have to be that dark silent noise floor. For it is just that quality over which everything else is painted with life like realism.

Coda
To say I am delighted by the metamorphosis of my Sanders amplifier would be a bit of an understatement. Even if I were to ignore all the l beauty and life it brings to music, then all the practical considerations should be a powerful inducement for ownership. If you take into account the fact that it can drive / complement any speaker you are likely to own, then common sense tells you it will serve as the foundation to build a complete audio system. Then add to that a 30 day in-home trial and a service warranty that is under normal use conditions is essentially lifelong. With that said, considering purchasing one becomes a real no brainer.

Remember Enjoy The Music & from me, Semper Hi-Fi.

Specifications
Type: Solid-state stereo power amplifier
Frequency Response: 5Hz to 100kHz (-3dB) 
Output Power: 500 Watts @ 8 Ohm (900 Watts @ 4 Ohm) 
Input Impedance: Unbalanced RCA 100kOhm, balanced XLR 1kOhm 
Gain: 26 dB
Damping Factor: Greater than 600 into 8 Ohm load.
IMD: Less than 0.002% @ 20Hz to 20kHz
Dimensions: 17" x 5.5" x 16" (WxHxD)
Weight: 54 lbs.
Price: $5500

Company Information
Sanders Sound Systems
12054 Deer Trail Road
Conifer, CO 80433

Voice: (303) 838-8130
E-mail : info@sanderssound.com  
Website: www.SandersSoundSystems.com