My DIY Amp project

[Hdale85]

Going to be ordering aluminum for the chassis. Also gotta buy a drill press probably something from sears for 100ish bucks. And ordering the FETS. Then I just needa get the tranny and caps for the psu and I think thats about it other then connectors and what not.

[Nathan P]

On the heatsink note, if you use the copper layer look up arctic silver compound, it's used in PC CPUs and is great stuff, 99,9% pure silver, best heat transfer coating type stuff ever.

[Hdale85]

Yeah I have about 3 tubes of Arctic Silver I build all my PC's so it gets used a lot.

[Johnloudb]

Going to be ordering aluminum for the chassis. Also gotta buy a drill press probably something from sears for 100ish bucks. And ordering the FETS. Then I just needa get the tranny and caps for the psu and I think thats about it other then connectors and what not.

Sounds great.

What type of package do your output transistors have? If it's TO-220, the metal mounting tab is likely connected to the drain of the transistor. So, you'd need to electrically isolate the transistor from the heatsink. But, you probably already know this.

From what I can tell the surface of anodized aluminum won't electrically conduct. At least my DMM measures infinite resistance, even when scratching on the surface. But, you'd need some teflon shoulder washers so the mounting screw doesn't electrically connect the drain to the chassis.

If anyone has better info on isolating transistors when mounting, I'd like to know.
I'll also be building an amp in the future.

[BobEllis]

Yes, the anodized coating is an insulator, but it's one of those "probably could get away with it but it's not the best practice" deals. Mouser and Digikey both carry insulators for various packages. Mica and grease is the old standby, with lower thermal resistance than silicone. The silicone pads are cleaner to work with, though.

Yes, be sure that the screws do not short out your circuit, and make very sure that there are no burrs to cut through your insulator.

[Johnloudb]

Yes, the anodized coating is an insulator, but it's one of those "probably could get away with it but it's not the best practice" deals. Mouser and Digikey both carry insulators for various packages. Mica and grease is the old standby, with lower thermal resistance than silicone. The silicone pads are cleaner to work with, though.

Yes, be sure that the screws do not short out your circuit, and make very sure that there are no burrs to cut through your insulator.

Thanks!