Columbia and Spice Engines

We have seen audio amplifiers move from valves to transistors. Of course the next step on is to place many transistors on a single substrate. Yes the integrated amplifier or monolith is born. Not integrated in the normal way we think of amplifiers with preamp, attenuators, selection switches, tone controls and power amps all combined under the one lid. But integrated depletion layers and resistors on a tiny slab of silicon. Less than 1" square and weighing but a few grams some of these chips can put out 100s of watts. My axe of choice when it comes to chip amps is the LM3875. My nanoo and mono blocks use the same chip and the amp modules shown here are what I base all my chip construction on. See the next Blog for more detail about these powerfull little amps or visit diyaudioprojects.

Spice Engines (LM3875 with 2000uf of low ESR line cap) are used in my mono blocks. In the nanoo the same chip was used with 5,600uf caps which form a Columbia Engine (bigger caps-the one pictured uses 10,000uf line caps). I have currently built Spice Engines with 1000uf low ESR line caps for a special project yet to be completed. Why the small and large caps? Simple, the smaller the cap the better the mid range especially with low ESR caps. You may lose heavy bass or extreme dynamics at high volumes with this design though. So I build different engines for different amp uses and styles. If you constantly played loud hard rock with difficult speaker loads-the Columbia Engines would be for you. Quiet jazz or simple jazz or classical trios or a lot of acoustic content with vocals-Spice Engines.

I always use the same chip amp PS. This has not varied to date. Usually UF diodes are employed but the one pictured used a diode bridge. As you can see from the photo the amp modules are very easy to construct and build into a full system. See the next Blog for more information. As noted below I will build these amp modules for $90 each.