Building A Stereo Tube Amp

Step 4 Layout/Planning

This is probably the most important step of the whole project, as Poindexter points out. Just putting everything in the right place to begin with can make the experience so much nicer. Being new to the while tube amp thing, mine isn't exactly pristine, far from it. But it works, so there.

You'll want to keep the power supply and the audio circuit as two separate sections/sides. All the tubes should go together in one area, and the output transformers somewhere nearby. Putting transformers too close together can apparently cause hum, but I'm not picky enough to complain about it, so mine are pretty close together. Some of the hum issues can be solved by putting metal covers over the transformers and grounding their cases properly. In this amp, the bolts fixing the transformers to the case are firmly attached to the ground plate by nuts. Apparently, the positioning of transformers relative to one another also helps to eliminate hum. If you rotate the transformers 90 degrees, so that they are not in line with each other, you get a certain decrease in hum. The angle isn't always 90 degrees though, so if you're very picky and patient, carefully adjusting the angle until it is optimum is definitely an option.

The circuitry in many tube amps is implemented a little differently than in other electronic projects. printed circuit boards are not always used, and they weren't here. It's more of a free-form circuitry type thing, with components soldered directly to each other, and terminal strips as little hubs of connections. This isn't the most organized way to do things, but it's faster than designing and ordering PCB's, and proto-boards can take up more room than is available in your enclosure (although now that i think of it they might work just fine).