My second GC (progress pics)

[maxw]

I really enjoyed making my first one.....so I sold it so I could make a second

This time its dual mono and regulated or high-cap with snubber, still haven't decided.

BrianGT amp PCBs, Digi01 reg PCB, 25Vx2 160VA transformers and 2x 6800uF caps per LM3875, custom aluminium case work by me .......but I think like the the last one it will be about 20 mins of soldering and 20 hours of casework

[maxw]

I got this bit of aluminium from a scrap metal yard for a couple of bux..

[maxw]

and cut it with a circular saw with a wood blade (!) into these:

[maxw]

Thats all for today

But I have a question though: If I mount the LM3875 onto the rear alu panel (which is 7mm thick) will that be enough of a heatsink?

[Stocker]

That depends on how much you turn up the volume. Quite possibly yes. If not, it would be cake to strap another heastink on the back (or inside). Run it loud for a while before you finalize the chassis' design.

[Nuuk]

It also depends on if you go with regulated supply or snubbered one!

[maxw]

Originally posted by Nuuk
It also depends on if you go with regulated supply or snubbered one!

Why? which one runs hotter then?

[Nuuk]

Why? which one runs hotter then?

The regulated supplies run hotter.

[maxw]

Originally posted by Nuuk


The regulated supplies run hotter.

I know that the LM338 produces a fair amount of heat but I am just talking about the LM3875 here because the LM338 will be mounted else where

I thought you were saying that the LM3875 ran hotter when using a regulated PSU.

[Nuuk]

I thought you were saying that the LM3875 ran hotter when using a regulated PSU.

Sorry, poor English on my part!

When you use a regulated supply with an LM3875 chip, the chip runs hotter so you need a decent heatsink.