Columbia Engines - Chip amp modules-LM3875.

What no printed cct. brd? With such a small component count (only three resistors) and the opportunity to do a little point-to-point wiring, why go any other way. These Columbia Engines (LM3875 chip amp modules with large line caps) lend themselves perfectly to this type of "get-your-hands-dirty" construction. With the ability to deliver an easy 56W RMS pc @ as low as .06% THD, these small, powerful and excellent sounding chip amps can be the centre of any high-end amplifier construction. The Gaincard from 47 Labs is based on a similar chip.

This is a view from the bottom and from here you can see the line cap (10,000uf) snubbers (.1uf polies). Also obvious is direct wiring to the the amp module with no clamp-down or plug connectors. Every connection is direct soldered. All wiring is heavy duty. Earth is a perfect "star" configuration. I use the component leads as part of the cct. Less than 1" of additional heavy duty copper connecting wire is used on the cct. brds. and this is an all one piece wire which is also the Ve- PS wire and part of the fuse assembly. The rest of the "hook-up" wire is the component leads themselves. No hook-up wire, no printed cct.

Resistors share the same mounting hole as the chip leads and are rapped around the chip leads, with one other connection if required and silver soldered all together. No tracks, no additional hook-up wire no added signal path length. The feed-back resistor is also mounted in the chip lead holes resulting in a feed back path the total length of the .5 W metal film resistors itself. And with the whole chip less than an 1" long, and this is the amplifier complete, you can only guess how fast these chips are. With excellent PSRRR and SPiKe these chip are very tough and dead quiet. Don't want to build your own - I can supply for $90 each (minimum of two) including in-line fuse housings and fuses. Why not build your own. Here's how: diyaudioprojects