Magtech Amplifier

Carl...you might want to give Roger a call or email. Mine never ran hot to the touch and I was driving Martin Logan CLSIIA's and Maggie 3.6's. Mine was well ventilated.

I may have to...The first one I bought died shortly after I got it, and he just sent me a new one. Great service. Apparently a part on a board was too close to something and they redesigned the layout to solve the issue.
He did say that 3.7's, indeed all jaggies, are very power hungry. And i do like to crank the volume ...just worries me when I see all the comments about the amp running cool...
Just got a used Ref 3 to drive it, and naturally it sounds better so the tendency is louder still..))
Thanks for the feedback...

Hi Brrgrr,

You may have seen my review comments HERE (Post #65) about the Magtech running cool.
The Magtech runs cool because its transistors have an extremely linear transconductance function and therefore do not require much bias to eliminate crossover distortion. Understand that most of the heat produced in a Class AB amp is produced by the bias current. The sole purpose of the bias current is to eliminate distortion. Through the use of the most modern and linear “Thermal Trak” transistors very little bias current is needed to eliminate all distortion and the amplifier as a result runs very cool. Impressively, the Magtech idles with each channel drawing only about 16 watts of power, so the total idle power used by the amp will be about 32 watts.

The inch deep heat sinks along both sides of the chassis, which look oddly insufficient for the amplifiers power rating, mercifully lack sharp edges and are child safe but closer inspection of the heat sinks however reveals there are no less than 53 fins, each with a surface area of 10 square inches. When you add up all this area, plus the area of the aluminium chassis, which also dissipates heat, the total heat sink area in the Magtech amplifier is nearly 10 square feet! As a result, the heat sinks are adequately designed to keep the amp cool.

That said, exactly how cool the amp runs will of course be a function of the load and the ambient temperate of the room. I used mine in an air-conditioned room and in that situation if the room is cooler than the amplifier, the amplifier will be barely warm to touch.

Kiwi,
My room is cool as well, but the amp runs very hot when I"m playing music at fairly loud volumes. It sounds great, I'm just wondering why all the reviews/comments talk about how cool this runs, when in my case this is not occurring.

Hi Brrgrr. How hot is very hot? Have you measured the tempurature? Can you touch the top cover without getting burnt?

While I have not tried the Magnapan 3.7 in my own system, I have auditioned them twice in dealer systems. They are not an especially tough load and dealers were using amplifiers in the 100-200w range. No issue for a Stereo Magtech to drive the 3.7. I used the Magtech to drive some ESL speakers that presented impedance ranging from 1.5 ohm to 250 ohms. No issue at all for Magtech and I could touch the top cover.