![\"IMG_3463\"](\"http:\/\/farm3.static.flickr.com\/2573\/3726053553_569dac1565.jpg\")
<\/a><\/p>\n(That’s a flickr-hosted photo so you can click on it to find a larger version.) I thought I’d put this photo up not because it’s a stellar example of my DIY skillz–it isn’t–but because I was amused at how it inadvertently ended up being a little showcase of circuit-construction techniques. On the right we have a PC board I laid out and had fabricated by BatchPCB<\/a>. You may recall having seen this PC board on my blog previously<\/a>. If you look closely at the photo above you’ll see that the chip labeled “HDAC” has been removed from the board. That was the quad 16-bit digital-to-analog converter I was going to use for pitch CVs. I don’t know what happened but I burned up two of those chips (at about $25 a pop) before giving up. I don’t know whether I made a layout error, whether my power supply was bad, whether I had overlooked some key piece of information in the spec sheet, or whether I just plain had bad luck. In any case, after the Magic Smoke came out of the second chip I decided to try a different DAC.<\/p>\n That decision led to the small board in the center of the row. That’s a PC board I etched myself. On its underside is a quad 12-bit DAC which actually has better INL specs than the 16-bit unit has. It also has the bonus feature of not burning up when I apply power to it.<\/p>\n On the left of the row is the brains of the system. It’s an Atmel ATMega128 proto board from Futurlec, mounted on a piece of stripboard with inline sockets. Just to its left you can see the optoisolator for the physical MIDI interface and a JTAG header for writing the code. (No ISP for me–life’s too short to prototype without source-level debuggers.) An ATMega128 is overkill for this application but I had the proto board lying around already. It talks to the DACs over SPI and TWI via the jumper cables between the boards.<\/p>\n So, there you have it: stripboard, hand-etching, and commercial fabrication all in one project. In true lo-tek fashion they’re all hot-glued to a piece of stiff cardboard. This is the sort of thing that I can get away with because my modular synthesizer sits on a table and doesn’t get hauled around the country on tour, unlike some people’s <\/a> synthesizers.<\/p>\n","protected":false},"excerpt":{"rendered":" I recently finished a MIDI to Control Voltage converter I’ve been working on for awhile. Here’s a photo of it before I installed it in my synthesizer’s cabinet: (That’s a flickr-hosted photo so you can click on it to find a larger version.) I thought I’d put this photo up not because it’s a stellar… Continue reading MIDI-CV Converter<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,1],"tags":[],"class_list":["post-1191","post","type-post","status-publish","format-standard","hentry","category-studio-nebula","category-uncategorized","entry"],"_links":{"self":[{"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/posts\/1191","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/comments?post=1191"}],"version-history":[{"count":0,"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/posts\/1191\/revisions"}],"wp:attachment":[{"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/media?parent=1191"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/categories?post=1191"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/studionebula.com\/blog\/wp-json\/wp\/v2\/tags?post=1191"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}