Tube Amp Monitor

Sparkfun contributor [Pete] really loves tube amps, but he’s a very safety-conscious guy who doesn’t like being electrocuted. This is a problem, since tube amps are usually very high voltage, and a small mistake can be fatal. To deal with this voltage issue, he built a tube amp with a control system built around a 6DOF v3 controller board. The control system is there mainly in case of a failure, automatically shutting off the high voltage transformer in any such event. It has the added benefit of filtering any 60Hz noise from getting into the audio, which happened before he installed the control system.

In addition to regulating power, the controller board also monitors bias points in the output tubes and displays its diagnostics on an LCD. Aside from getting great sound from the tube amp, [Pete] made it look great too, installing colored LEDs under the tubes. We love his design: just because safety comes first it doesn’t mean cool-factor can’t come in a close second.

5 thoughts on “Tube Amp Monitor

  1. Really cool project, however I’d say that it’s not the best use of a $400-ish board. For the amount of functionality required for a safety system, even a PIC would be overkill. Neglecting the voltage readout part, you could accomplish the same thing with some op-amps.

    But damn, it looks so cool.

  2. @justin:

    Yeah, this is something that’s concerned me about DIY electronics nowdays: the over-emphasis of microcontrollers. It’s so easy to just code up a brute force solution to most problems that we’re losing the art of designing elegant circuits. (It’s not just DIY either, commercial electrical engineering is leaning this way as well)

    Still, cool project!

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