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Steampunk SOHA tube headphone amp

written by Gia Ferrari on 2011-05-17

This is a project that has been floating around in my head for a while. It had fairly innocent beginnings - a few years ago, I bought a nice pair of Audio-Tecnica ATH-M50 headphones. They work great, but I thought adding a headphone amp would make them sound even better. I thought of building the excellent CMoy amp, which the standard DIYer solution to this desire. I decided, however, to use this project to satisfy my curiosity for those charming relics of the past: vacuum tubes. If nothing else, I figured it would make me appreciate today's solid-state devices to a greater degree 🙂 Since I'm an absolute noob when it comes to tubes, I settled on the simple SOHA design by by Alex Cavalli, Mark Lovell, and Bill Pasculle, hailing from HeadWize. It's ideal, since it has a simple power supply, no lethal voltages, and uses only one tube. It's also mildly interesting in that it uses old tubes along with modern high-quality op-amps. That's all well and good, but about the all-important case? You can't have a cool electronics project without a swanky case. Many ideas kicked around: half-plastic-half-wooden case to show the marriage of old and new tech (discarded because I'm not nearly skilled enough in fabrication to pull that off) , a case made from a clear acrylic tube (tube amp! eh? EH?), even an IKEA photo frame. Ultimately though, I realized Steampunk projects are awesome and headed off to an antique store to find a suitable box. $15 later, I had a great box. Guy says it's probably a small-scale sample used by a chest salesman or something. It's pictured below. I haven't finalized the external layout yet, but it's going to involve tubes sticking out the top and the (ab)use of whatever other steampunky bits I have around.

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