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Extending the soundscape of a hexaphonic guitar pickup
sorveltaja:
Ade, thanks for the heads up.
I'm using Rhinoceros to draw the pcb layouts. Tracks can have any width, but I've used mostly the "beefy" 1,8mm ones, as they seem to transfer rather well. Sometimes, if some pcb has very thin traces, I just re-draw it to have thicker ones.
I guess all that could be done with something like 2d-vector software perhaps? I wish I could recommend something, but as I've used Rhino for pretty much everything, from 3d-modeling to 2d-stuff for years, I haven't looked for the alternatives. Ideas anyone?
I haven't heard of Martin Molin before, but will check it out. Thanks for the link :beer:.
sorveltaja:
I was going to test the hex pickup today, with the step waveform generator. I had completely forgotten, that it has a very quirky power connector, that needed to be wanked around to make a contact.
Like wallwart ones, that has a center hole in the plug. Both the plug, and socket are brand new, so perhaps they are of different size.
But yeah, that bugger ended the testing session effectively. Instead of feeling like flattened pancake, I'll get armed with the trusty stomping shoes.
I'm thinking of ordering mono jack -type connectors instead. Also the whole power supply scenario needs to be replaced with something more 'universal', or 'centered', having several regulated 5 and 9 volt outputs, and (possibly variable)split power supply outputs for 15-18 volts too.
Hmm. So many plugs and sockets, and wires. Maybe it would be a better idea to gather all, so far built circuitry, including power supplies, in a one larger box, that was mentioned earlier.
So that will be the subject of the next sub-project.
Other than that, I've been trying to find an article, that is about building 8-channel vocoder. I used to have copy of that article in printed form, but can't find it anymore. If memory serves, it was originally in Keyboard magazine. Even online search didn't give any usable results, although when I get to the mood for searching something, if it exist online, I tend to find it.
Anyways, I built that vocoder in the past, using perfboard. Apparently it didn't survive, having wildly running wires around, and all that stuff. But it was good fun to play with.
I'll have to admit, that having a vocoder is an obsession for me, as it could be used in so many more ways, than just 'talking' instrument. For those interested, Kraftwerk is one of the first/most well-known groups, that used variations of it to make the "robot" voices. It was used also by Walter/Wendy Carlos in movie Clockwork Orange's soundtrack. Cylons from Battlestar Galactica, and so on.
Fortunately, there are other versions to build. Possible candidates are the Elektor, Okita, and Mfos(music from outer space) ones.
Besides all that, easy shortcut could be to buy one of the digital ones, that have reasonable price tag, but in my case, no way Jose. There just isn't easy ways to modify/abuse that kind of devices.
sorveltaja:
The 8-channel vocoder, that I mentioned earlier, I found stuff about it on my hard drive. What makes it better, is that it's so much simpler, than any other ones that I've checked so far.
I'm going to draw the pcb using this image, as I haven't found any better images of it:
Length of that pcb is about 430mm. Too big for me to make, so I'll divide it to 3 or 4 parts.
sorveltaja:
The vocoder pcb almost redrawn:
It has some tight spots, that needs to be taken care of, though.
I'm redrawing the component designators also, as the image is too blurred to be (possibly)transferred to the component side of the pcb(haven't done that before, but well see):
As can be seen, it's Paia Vocoder. Originally it was published as a project in Keyboard Magazine by Craig Anderton, in the 80's.
There doesn't seem to be too much info about it on the net, as many of the builders seem to look for fancier, 12, 14, 18, or even 24 channel ones.
I have a feeling, that this humble, 8-channel one is overlooked. One reason for that could be, that the actual kit on the Paia website is out of stock.
But on to the pcb itself. As mentioned before, it will be divided to 3, 4 or 5 parts, and probably stacked together, to make it a whole lot narrower.
Of course there is one major factor, of how to verify, that the redrawn pcb actually works, as it should? I'll be doing some checkings/comparisons with component designators, and what not, before dividing it into smaller parts.
It uses 5 x 4136, and 1 x 301 -op-amps, which are fortunately available from my local supplier. It also uses 4 x 570 or 571 compander chips, that I already have in my shelf. Rest of the parts are resistors, pots, caps, switches, and connectors.
It requires bipolar -15/+15V supply, which takes us back to the previously mentioned need to make a more 'universal' power supply.
After all, I have to remind myself(all the time) to take only one step at a time.
sorveltaja:
Divided vocoder pcb:
I decided to use 75 x 100mm pcb's as they are already available in that size. Cutting the pcb is something, that I've never managed to do properly.
On the other hand, I have only used 1,6mm boards, and have scored them to get cleaner results, but they seem to be too thick for that, and the edges tear. Maybe 0,8mm ones, which I'm going to order next, are more suitable for the 'score and snap'.
While reading through the vocoder's assembly and user manual, there is a mention about "clarifying mod". It uses 4 x 084 op-amps, and some resistors, so I'll order parts for that too.
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