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Amp Camp Amp Version 1

I decided to have a go at building my first amplifier.  The amp camp amp by Nelson Pass has a low part count, and is designed with highly sensitive drivers like the Fostex 206EN I own in mind.  The schematic and theory is freely available here.

I ordered the components, a mix of RS online and ebay.  I build the circuits on copper strip board.  I had planned all along to dissipate the 50W of heat using a CPU heatsink.  This one is a Zalman heatsink I think.  It is rated to 90W dissipation with the fan active.  Conveniently it has a metal bracket with holes to attach to a motherboard, which means I could bolt it down to a case with ease.  I used a DC-DC step down circuit from ebay to step down the 19VDC switch mode supply to 5VDC to (under)drive the cooling fan.

I find the heatsink aesthetically pleasing:

Making a box:

Clamping, gluing:

I spent a while deciding on a hole arrangement for the various connectors:

Found some scrap metal to act as a heat spreader beneath the MOSFETS, which are to be sandwiched between the box and the CPU heatsink:

A more finished box:

Cutting a hole in the top for the CPU heatsink to peak out of:


Stained and varnished the box with a rustic look (intentional, honest):

Placing the MOSFETS, prior to clamping down with the heatsink:

Used kapton tape to electrically insulate the heatsink from the gate of each MOSFET:

The finished prototype, eek spaghetti wiring, was too excited to tidy:

A satisfying connector arrangement I think:

Very impressed with this amplifier.  Only 5W of audio power per channel, but maximum volume is unsocial.   Completely destroyed my understanding of audio power: