LED mods for Arp 1601 clone

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

My finished 1601 build

Klee, switched-on cables

Klee is starting to get cabled up!

I chose to go about it using flat cables: These result with somewhat as clean a solution as the “bundle method” which Klee build issue 6 manual suggest using, but without the added work stage of having have to bundle up the cables.

It’s been such a long time since I last did cable crimping, that I conveniently forgot how much I actually hate the task. Starting out it took me about 30 minutes to cobble together the first 8-pin cable! Subsequent cables of course went a lot faster.

Nonetheless, the vexing start made me think that it might be a good idea not to overly annoy myself with this. Build projects are supposed to be fun and all that, right? If I was to approach the work stage by, say, making a maximum of 4 cables per day, it should prevent excess of vitutus maksimus arising (pardon my finnish). This way I’ll have the cables sorted out some time early next week. Good enough pace for me.

Not too many cables installed, and things already look a bit messy..

Klee, mech fuckups

What a nice week of milling fuckups with the Klee mech.

After milling the top panel, I noticed I forgot to draw in three SPDT switches. No idea how this slipped past my radar, as I did check the drawings many times prior to milling. Situation was pretty much saved by the fact that I had at least reserved space for the switches. Just add the holes and the project is back on track..

Three missing.

.. or it would be, had I just drilled these holes by hand. Instead, I chose to go all fancy and use the router! Aligning the board on the CNC table for adding these holes was of course a total annoyance, but I got it right eventually.

Just to have a bit of extra crap thrown in, the CNC program decided that these three holes should have a 1mm offset on Y-axis. Something I of course noticed right about the moment the milling bit went in :). No idea why it turned out this way, after all zero location was ok and I did check for it three times. But whatever, the 1mm difference was persistent so I just compensated for it by offsetting the zero location.

Klee, parts parts parts

As it turned out, Farnell UK wanted to sponsor my Klee project a little bit by hooking me up with some parts! Having gone through a good amount of sourcing for this project, this lead me to think about parts in general. As things are on hold anyway until I get the SP8T rotary switch, I might as well go through some of the items I’m planning to use..  Good news is, I do now have a source for the SP8T so I can soon shut up about it. Yay for that \o/

The boring shit

Anyone who’s into DIY electronics (or repairs) probably knows that selecting and sourcing all the bits & bobs needed can (more than often) prove bit of a headache.  Building up knowledge of reliable/usable parts sources takes time and any short-comings here can easily bring a project to a halt. Not that every shop stocks every single part you might need either.. Add things like specific part properties or plain ‘meh, done that already‘ to the mix, and you’re instantly in need of a wider shop selection.

Klee, panel sketch #2

Nearing final version with the panel layout! For this one, the overall width narrowed down to about 34cm, so the final enclosure should definitely fit well within “desktop limits” too.

2nd version

Next up on the “design menu” would be completing the sub-panel design. This will most likely require some minor adjustments to the layout too, as I’m yet to completely factor in all parts according to their third dimension too. Let’s see how tricky this gets.. Draftsight is 2D, so all the “3D” has to be done with physical items, pen and paper.

Parts-wise I’m still stuck looking for that (damn) SP8T switch, so the current layout is dimensioned according to a SP12T Lorlin rotary. In the picture above, this is the biggest circle immediately to the right of slide potentiometers. Hopefully these rotary switches come in enough a standard size, that leaving a clearance of few millimeters around the part will make most variants fit!