flashgo
DIY Practitioner
Nice Job Flash
I see you have the speaker protection boards in there as well, did the heat sink come in one piece for that & the NCC300 ?
Hi Alan,
It's the original NAP135 heat sink, and it accommodates both boards on one heat sink.
Les warned me that you can't use the normal Avondale mounting scheme because the shelf on the heat sink is so thick (0.335") that any extra spacing will prevent the power transistor legs from showing through to the PCB. Instead, Les advised gluing some thin mica insulators onto the bottom:
I don't know if that's visible enough, but there's fresh glue between the holes on the metal lip. This was just before laying the micas into place. This worked so well, that there was still space for ceramic insulators between the transistors and the top surface. I kept the original tubes inside the passages through the heat sink lip.
The SPM1 is labelled "Loudspeaker Protection & Fan Control Module", so there's a lot packed onto the board. I still have to tune the fan module, but eliminating the turn on and off thumps is great! It adds to the sense of "blackness" with this amp. Meanwhile, the transistors and the heat sink are barely above ambient temperature!
Flash
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