Couldn't agree more. All people in his business, or any other for that matter, could lean a lot from his business practices. A rare one!
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Well, the amp died last week. One of the 15 amp fuses broke:glass shattered, but the metal remained in tack. The speaker fuse blew, and no damage done. As to the possibility of cables occulting, as I am using Sanders speakers cable, I'm pretty sure I am ok on that matter. Will be sending it back today for repairs, and perhaps Roger will find something that will explain the heat when he does repairs. Given all the comments I've seen on the web about how these run cool, I'm curious if I just got one with an issue that slipped by and showed itself when connected in a system. This is the second trip back...first one died due to a bad board design that was changed shortly after mine was purchased, and Roger simply replace the amp. Excellent guy to deal with, and I'd recommend his products no question asked. Crap happens!! |
Most of the Coda Amp's are also using the Thermal Trak technology developed originally by ON SEMICONDUCTOR Company years ago. David Hafler back in the early 90's utilized the Thermal Trak technology with poor results due to voltage problems with his amps. Many of the Hafler amps at that time blew up and Hafler had a lot of refurbs for sale, but the problem became so severe that it caused Hafler to go out of business. David did much better with his Dynaco kits back in the early 60's. Doug at Coda several years ago informed me that yes indeed all the Sander's amps are manufactured by Coda in final completed section's and the final assembly into completed unit's is done by Sanders Sound Systems. |
If a Thermal Trak transistor fails it will cause the amplifier to run very hot on that channel even on idle. The entire top of the amplifier will be hot but if a measurement is taken one side will be hotter than the other unless there has been a failure on that channel too. I am not sure if there is a situation where a Thermal Trak transistor not working properly but not completely failed will only show up when the load is demanding. If anyone has a problem with a Magtech amplifier they should call or email Roger Sanders. He is very responsive. It is especially helpful if you can report actual temperatures instead of relative terms (e.g. hot). A multi-meter with a temperature probe is one useful option to measure temperature. |
It sounds like you may have a problem with high frequency (ultrasonic) instability. This may be caused by your speaker cables. Roger has a white paper about that on his web site and says that can cause the amp to run hot. I have to of his amps and they have never even gotten warm to the touch. I would recommend calling Roger and discussing it with him. |
Kiwi, It's hot to the point that keeping your hand there for more that 10 seconds starts to be painful. This is when the speakers are being pushed, and I like the volume up . I do know Mr Sanders told me that maggies are very power hungry, and take a lot of watts when they are pushed loud. Maybe it's time for the mono versions... Just concerned that this may be shortening the life of the amp, given all the heat. Maybe it's nothing to worry about... |
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. |
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. |
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... |
The Magtech is a superb amp, and not just for the money. I have two of them, driving the woofers and the panels of my Sanders 10c. I've owned many amps over the years, some much more expensive and both tube and solid state (e.g. VAC, Ayre MX-R). The Magtech is the best compromise of sonics, stability, efficiency, and cost that I know. |
I am presently using both Sanders Magtech and Sanders ESL MKII stereo power amplifiers. They replaced European amplifiers which were 3x the price. I was so impressed I penned a user review that can be found HERE . The secret about how good these amps are does not still seem to be out. Massively powerful, compact size, run cool and use hardly any power in idle. My only caution to owners and potential owners is don't switch them off! They take quite a while to come on song. |
Driving a 1 ohm load at 20 khz is different than driving a 1 ohm load at 30 hz. Stats have a very high impedance until you get to the high frequencies. Then the impedance drops like a rock. I expect the Sanders amps would do well with the Scintilla's but I would want to hear them first. Pretty sure they have a 30 day trial. You could also just call Roger Sanders and ask him directly. |
"So, does this mean that the Magtech amp is stable driving a 1-Ohm impedance?? Yes! My Martin Logan CLSIIAs drop to about .8ohms and the Sanders amp never even broke a sweat driving them. They also drive my Magnepan MG3.6s without any strain either. I agree with Cerrot, Roger and Angela are wonderful people to deal with. Some of the best in the industry. |
Oh good I found this thread!! :-) I've been eyeing this amp (both stereo & mono versions) for my 1-Ohm Apogee Scintilla. Does any of you know whether this amp will be able to drive a 1-Ohm load? The info on the website states that: The regulator in the Magtech amplifier maintains a stable voltage regardless of load or reasonable changes in the line voltage feeding the amplifier. Unlike other amplifiers, the distortion in the Magtech amplifier is virtually unchanged regardless of power level. The bias is stable regardless of load. So, does this mean that the Magtech amp is stable driving a 1-Ohm impedance?? Thanks for your inputs. |
Uhrn.... Norm, if that is the case, you are in good company... All solid state amps I have broken in this far (high efficiency class D) have taken between 1,000 and 1,500 hrs to break in.... and even my previous high bias class A/B amp, the venerable Rowland 7M, of which I have been the proud 3rd daddy, took about 24 hrs of steaming before giving its best after its power was cycled down to standby for a couple of days or so. I suspect that, if I needed instant gratification, I would need to change hobby, or at least target very different amps. Of course, ever the empiricist, I remain open to possibly discovering a high end SS high-efficiency amp that is not plagued by "late bloom syndrome". Yet for now, ripening cheeses, aging wines, and breaking-in amps... remains just part of the ever patient fun. Saluti, G. |
Primare_cd31, I am using the Magtech right now on my LSA1 Statements. I did review it for Dagogo. As you say it is very powerful, well made, fairly light weight, and certainly inexpensive. I am at odds with Roger Sanders about his excellent amp. I have found it does not like to be turned off and takes a good deal of time recuperating if this is done. Also, it is very responsive to proper isolation and to power cords. It also takes a long time to reach its best. My unit now has many hours on it. It is on a StillPoints Component Stand and has the Synergistic Research MIG isolation feet under it and is driven by a Syn. Res. Halograph A power cord. Each of these made a significant improvement in my sound using this amp. There is a clarity and effortlessness to this amp that I have not had with other amps. Of course, I have not had many very expensive amps, such as the Ypsilon, Tidal, or Sovereign amps in my system, but I see nothing wanting using it. I also know that it is selling quite well. |
