The diyAudio Firstwatt F6

The far transistor needs to be over the centerline of the 5U case's heatsink - it is a two-peice extrusion, and this way each Mosfet will be on it's own heatsink.

The 4U is a single extrusion, so it being off-center means little.

A bit closer to the transformer is not a bad idea however... 🙂

Jim, I am thinking about getting another chassis but thinking something that will work with more projects here and possibly going F6, would you suggest the Deluxe 5U?
 
Jim, I am thinking about getting another chassis but thinking something that will work with more projects here and possibly going F6, would you suggest the Deluxe 5U?

There is no doubt that bigger is more flexible, more room inside, more heat rejection, etc... of course this comes at the cost of being, well, bigger. I always suggest to people this; make a quick mock-up of the chassis out of cardboard and see if it's as big as you think. If it's ok, wonderful! (And remember, Papa said "There is no such thing as too much heatsink!")

The 4U is still plenty enough chassis for F5, F5C, F4, AJ, F6, Honey Badger, and 6-deep Burning Amps. You only really need the 5U for F5T and Burning Amps with a second set of output transistors.
 
Just for the record AJ runs hot in 4U 🙂

Yes, it's right on the edge. Turning down the bias a bit helps.

Ooh -- look what showed up in the post today... 🙂

Beta testers, I'll get them sent off today.
F6_proto.jpg
 
Last edited: