Hi I was wondering if anyone else has thoughts about this I have a couple of 16-MCD1000D M class series Memphis amps I came a crossed this on the output side I assume there is a extra output fet location on the board that is not used on both sides of the amp where the 9640 and 640 outputs are located does it hurt to add another output fet there or not because I have one amp with all output slots used on the board and seems to work good I do know the older style Memphis amps studio verion 16-st1000D only runs 2 irf640s and 4 irf9640s per side if I added a extra fet to each side of this amp it would either be 3 irf640s 4 irf9640s or 2 irf640's and 5 irf9640's I just don't understand what Memphis's purpose was to add the extra spots on the board if they wasn't going to be used does it improve the amps performance or life span or is those empty slots there for testing purposes?
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You need be careful when posting the model number. Sometimes a small difference in the model can mean a completely different amp. Is there a D on the end of the model number on the amp?
The extra spot is for an N-channel FET. That's the only possible addition that you can make. They may have left it out because it was unnecessary. The extra load that the transistor would present to the driver circuit may actually make the amp less reliable because it would add stress to the drivers. If it's your amp and you want to experiment, feel free to do so but if it causes premature failure of the drivers, it may take months of use for them to fail. The amps are reliable as they are. The only thing you may want to do is replace the IRF640s with IRFB31N20Ds.
The extra spot is for an N-channel FET. That's the only possible addition that you can make. They may have left it out because it was unnecessary. The extra load that the transistor would present to the driver circuit may actually make the amp less reliable because it would add stress to the drivers. If it's your amp and you want to experiment, feel free to do so but if it causes premature failure of the drivers, it may take months of use for them to fail. The amps are reliable as they are. The only thing you may want to do is replace the IRF640s with IRFB31N20Ds.
Mouser, Digikey, Future and Arrow.
https://octopart.com/search/modals/allPrices/e65c2f53ef95399b
https://octopart.com/search/modals/allPrices/e65c2f53ef95399b
Yes I do the insulator is torn from previous owner cutting it while trying to remove the spring clips and yes I do because when the spring clip isn't installed I pushed each fet one by one to the casing soon as the fet touches the casing the amp starts shorting going into protect mode
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Confirm that the transistor doesn't have a burr on it. It takes a fairly large tear for a flat transistor to contact the sink.
There are a couple of options (at least). Since the rectifiers are fully encapsulated, you can remove the insulator from those (applying heatsink compound between the rectifiers and the sink) and cut a piece of it to place behind the shorting transistor. You could also use a different type of insulator, like kapton tape. If you use a different type of insulator, you need to use the same type of insulator behind all parallel transistors.
There are a couple of options (at least). Since the rectifiers are fully encapsulated, you can remove the insulator from those (applying heatsink compound between the rectifiers and the sink) and cut a piece of it to place behind the shorting transistor. You could also use a different type of insulator, like kapton tape. If you use a different type of insulator, you need to use the same type of insulator behind all parallel transistors.
It's typically very expensive ($1+ per transistor). If you find it for a reasonable price, post a link.
The following is supposed to be a 12"x18" sheet. If it's the right material, it's a fairly good price.
A15397-03 Laird Technologies / Thermal Solutions | Mouser
The following is supposed to be a 12"x18" sheet. If it's the right material, it's a fairly good price.
A15397-03 Laird Technologies / Thermal Solutions | Mouser
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