- Sanders Magtech Stereo Amp(click here to read the PDF of the article)
Robert E. Greene
This has to be short, so I’ll get right to the point: If you paid $5000 or more for a presently available amplifier and did not check this one out first, you should have. There are, in some important ways, very few competitors for this design.
And some of these, like the Lightstar and its relatives, you cannot buy any more. This is not to take anything away from other power amplifiers, many of which work really well and sound all but perfect when they are not being stressed out too much. But when the going gets really tough, not just for loudness as such but for the complex and current demanding loads that speakers present in the real world, what one needs is a regulated power supply. Hardly any contemporary amplifiers have this; this one does. This idea is not news to long-time TAS readers. Back in issue 25(!), Dave Wilson, then a TAS reviewer, wrote of some solid-state amplifier “The power supply is not regulated per se, but it is so stiff and so responsive that even on very deep, very loud material it is like unto a brick.” Implied was the idea that regulated would be even better!
In practice, regulated power supplies are a true rarity in the output stages of power amplifiers of any substantial
power, though they are almost universal in amplification devices at lower signal levels like preamps. They are almost universal there because they work better. And it seems they work better for large-signal purposes, too. They are just hard to arrange.
I do not have room to explain what is going on here or even what a regulated power supply is. You can get the basics at Wikipedia and there is further information on this amplifier specifically on the Sanders site (sanderssoundsystems.com).
The Magtech does not have a switched-mode power supply, the usual way to get power supply regulation in a practical form for power amps. The Magtech has a patented linear regulation system, and that makes it unique.
Does that matter? I have not run double-blind tests and so on, and of course there would be other variables since there is no way to un-regulate the regulated power supply for comparison. But in informal albeit concentrated listening, the Magtech not only drove the tricky Prince II electrostatic load very well, indeed, it also delivered truly superlative performance into dynamic speakers. The sound from my Harbeth M40s (original version) sounded precise, controlled, defined, dynamic, perfectly balanced, and extremely clean with unusually silent background and extreme solidity even in demanding passages. Thundering piano music, for example, was as solid as a rock. The Sanders Magtech amp has power to spare, 500 watts per channel into 8 ohms, 900 into 4. But it sounds as if it had infinite power into anything with total stability. The Sanders Magtech joins (really only, in my experience) the Lightstar family and the DALI Gravity in extreme ability to handle anything and sound perfect while doing it. An instant classic in my book. Try it before you decide I am exaggerating. REG