Still time for a quick one before it’s ‘BYE BYE 2016’! :)
While building my TTSH I also got myself a DIY kit of a Arp 1601 sequencer clone. The build itself was so straightforward that I didn’t see the point in blogging the details. However I made some LED mods to it and thought maybe this would be of interest to owners of this device. So if you ended up here looking to change the color of LEDs on your Arp 1601 clone, look no further! If you’re in a hurry, check the summary section at the end of this post.
While you can also find my posts related to the mod at Muffwiggler (Muff) forum, I thought my blog here is a more compact way to present the information. For one, since forum threads at Muff are created by product / project, there’s a number of discussions going on at the same time (esp. if a DIY build). So a thread can become convoluted. Second, threads which span years (or multiple production runs of a kit) can become l-o-n-g, adding to the ‘needle in a haystack’ effect. Third, if you’re not logged in the board system won’t show post attachments or the like. So it can be quite the dig looking for information you need.
But don’t get me wrong, I love the Muffwiggler board and a lot of highly skilled people dwell there. It’s just that often the format isn’t good for finding information that you need instantly.
Well maybe my ramblings aren’t either, but let’s not follow that tangent! :D
If you’re all new into how analog synthesizers can be controlled, you may first want to take a look at this Wiki article on CV/Gate for some jargon busting. Other than that, let’s dive right in.
Among the first electronics mod I wanted to add to my TTSH was the Gate Booster. To fully open the ADSR envelope generator of TTSH a +10VDC gate needs to be applied, thus in it’s stock config the envelope can’t be fired properly by using eg. any external gear that outputs a +5V gate. Add to the common CV/Gate specs, the TTSH envelope generator also needs a trigger signal (very short pulse) to work properly. This can be used to restart the envelope without disabling gate signal.
So what the Gate Booster does is, it converts low voltage level gate signals to higher voltage and generates the trigger signal from the gate input. The particular circuit board I bought for myself is this modified version (sold by Oshpark) with a socket for a Midimplant MIDI-to-CV/Gate converter board. Having MIDI (keyboard) input just made so much more sense than eg. building a CV keyboard like the Arp 3620.
A little personal history: Macintosh Plus, commonly referred to as “linnunpönttö” (birdhouse) in finnish, is a computer I got to test hands-on way later than it was released. By the time I did, Amiga 500 had been ruling the home computer hobbyist scene for years. Familiar with A500’s awesome capabilities the Plus (with it’s small gray-scale monitor) simply was, in comparison, a uninteresting relic.
Fast forward ten (or so) years and I found myself looking at one in a second hand store. With a near yours-for-free-if-you-take-it-out-the-shop price tag, the Plus powered on nicely but came only with a keyboard (minus one key cap). The lack of OS disks and mouse made it pretty much a unusable piece-of-shit. Nonetheless, I took it with me and stored it away to wait for closer inspection. Then life had its funny ways, and the Plus sat in the basement waiting.. and waiting, right up until this august when I dug it up thinking “maybe it’s about time..” And here, we start to close in on this post.
There is a lot of info about Mac+ out and about the net. But as it often is with these retro systems, not everything is necessarily applicable or usable, or you’ll simply come across a bunch of dead links. One of my ideas with this post was to compact my findings and provide one usable solution for “how to get that damn can of worms up and running“. If you, like me, acquired a second-hand Plus with just a keyboard, this one is a definite read for you. Maybe you’ll have a little less grandiose mission getting your Plus back in action ;)