The BrianGT Non-Inverted Gainclone (LM3875)
| Introduction This simply must be one of the simplest projects ever. The above link goes to chipamp.com, where a fellow named Brian Bell, aka BrianGT at DIYaudio, sells kits for gainclones. I bought an Avel transformer (300VAC to 30-0-30), followed the directions, and had a working gainclone in mere minutes. The quality is breathtaking for the $80 spent on the total project. It was so simple that I decided to challenge myself by building a discrete preamp. Otherwise, here is a play-by-play of construction. Click any thumbnail picture for a more detailed picture. |
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| Heatsink: I found a pretty blue leftover heatsink from one of my CPU projects from ages past. |  |
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| The arrangement didn't quite work, and I had difficulty attaching the chips to the heatsink. A piece of wood and a long screw did the trick. |  |
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| Testing Phase: Even without proper grounding, it already sounds awesome. |  |
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| Wiring: This is a leftover from a project I did on the house. The individual wires are braided, but they were still thicker than the posts on my 15 amp mains connector and switches. I have average sized hands, for reference. |  |
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| Chassis I: This wood is leftover from a shelf that was left in the house when we moved here. It also provided wood for my Hohl Flutes. Anyway, since this amp is really not going to be seen, I thought I'd practice at woodworking by putting the thing together with pegs I made. |  |
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| Chassis II: Here is the chassis and chassis wiring. Ignore the grounding scheme. I don't know for sure, but I think that this grounding scheme, combined with a key broken soldering joint, will cause a purchase of new transistors for the preamp. Otherwise, the chassis works great. |  |
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| Nuuklear ReaGTor: The corny name I coined for wiring the BrianGT and Nick Whetstone (aka Nuuk at DIYaudio) preamp together. Click here for details on that. |  |
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