Posted: Tue May 22, 2012 1:06 pm Post subject:
Re: 'T was brillig,..
PHOBoS wrote:
I just finished the Jabberwock...
Wow, beautiful box!
I breadboarded the Jabberwock yesterday, but I think I made a mimsy or two, because it doesn't seem to work right. Alas, I'm leaving town a few days, so no time to debug it until next week .
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
Posted: Wed May 23, 2012 10:11 pm Post subject:
TH Dual EG
Not quite so spiffy looking as several other recent entries (I *really* love the look of the jabberwock box; then again I'm not that good at drawing/painting), but a step forward nonetheless...you can compare the MTS-100 with the ADSR and see the steps forward. And plenty of learning for what not to do next time
(I like to think this is the modular version of JingleJoe's ramshackles... )
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On the bench, showing the ganged envelopes
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In the "rack" such as it is
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Joined: Nov 10, 2011 Posts: 878 Location: Lancashire, England
Audio files: 14
Posted: Thu May 24, 2012 11:24 am Post subject:
Re: TH Dual EG
elmegil wrote:
(I like to think this is the modular version of JingleJoe's ramshackles... )
thats going to be friggen brilliant even if I do say so myself _________________ As a mad scientist I am ruled by the dictum of science: "I could be wrong about this but lets find out"
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
Posted: Fri May 25, 2012 5:36 am Post subject:
It's a DS203, or DSO Quad. The original design is by Seeed Studios but I got this on ebay at a significantly lower price. They're open source hardware as well as software, and I would say it appears that this is a clone; the back says www.minidso.com which is a chinese board...
It has taken some getting used to some of its quirks... And it has an issue (assuming it's a straight up clone, the original design has this issue) where the capacitance on the input is too high for it to actually make the originally stated 72MHz input claims. Now they just say up to 72M samples/s .
However, since I'm doing audio work, not RF or something else way up there, I am not having any problems with it.
I'm used to the quirks (didn't take too long to figure out ways around things that don't work as I'd like) and it's been invaluable. No way could I have troubleshot the EG without it. I could have gotten a used Tek or similar from ebay for about the same cost, but then I'd have issues with "the boss" about where to store a big old boat anchor scope. And my workspace is pretty limited anyway....
Joined: May 15, 2009 Posts: 96 Location: Lawrence Kansas
Audio files: 3
Posted: Tue May 29, 2012 8:09 am Post subject:
I had twins (oscillators that is...)!
My first proper oscillator: a dual, variable pulse/ramp variety with plenty of in's and out's.
The core is based off of Ray Wilson's 'variable skew lfo' and was then completely bastardized for audio rate use, +/-4.5V rail power, and adapted for my control scheme (current control). I tacked on a cross fader to mix between the pulse and ramp waveforms and added an amplifier before the output (basically a vca...).
Controls row by row:
Row 1: Control signal out, Frequency control input, Amp. control input, Audio out
Row 2: Control out level/depth, Amp. gain, Waveform mix
Row 3: Frequency control, Frequency range (low, med, high), Wave tilt/pulse width
I was shooting for something along the lines of a buchla 258, and was happy with the way this design came out; lots of great fm and cross-mod opportunities!
Fun fact: there are four vactrols (hand rolled) per oscillator, so eight per module, or 16 between the two!
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Joined: Mar 07, 2007 Posts: 4579 Location: London, UK
Audio files: 172
Posted: Tue May 29, 2012 2:13 pm Post subject:
Adam, congrats on having proper VCOs and they look great. _________________ Garret: It's so retro.
EGM: What does retro mean to you?
Parker: Like, old and outdated. Home,My Studio,and another view
Here is a video showing some mods I added to a Roland JX-1 that I restored.
I got this beat up Roland JX-1 for $25. a bunch of keys were broken, so I moved all the good ones to one end. I also cleaned it up both outside and inside. I think a cat was using it as a bed - it was full of cat hair.
The synth worked fine and sounds good, but I found it to be a little cold and dull. I decide to add some mods to add analog warmth and uniqueness to the sounds.
MS20 Filter
I added a modified MS20 filter. I was added distortion anyway, so I removed the diodes in the resonance bypass and used a 18K filter, plus some other minor mods to get it to work and sound the way I wanted.
Distortion
I used 4069 distortion circuit taken from a Wasp schematic. The amount of distortion is controlled by the master volume level that is sent into the circuit.
Stereo
The JX-1 has stereo sound and effects, so I kept the setereo image intact by duplicating my circuits and using dual pots for control. Since the resonance on each filter runs at a slightly different rate, it creates a nice stereo image effect.
More Power
I added too much for the 100mA +/-12V regulators in the JX-1, so I had to replace them with 1.5A ones. I also increased the capacitors used for the 12V power regulators.
Also, an update on my portable stereo speaker box. I changed it to 20 times amplification and added the option to use a DC power adapter.
Joined: Mar 20, 2012 Posts: 2177 Location: Chicago
Audio files: 16
Posted: Sun Jun 03, 2012 8:23 pm Post subject:
That's awesome. A week or two back I picked up a JX-1 in basically the same condition (I think I may have more keys ) for about the same price. I didn't have the Roland power supply, but I had a 12VAC transformer and a plug that fit, so now I have a supply too . I haven't yet figured out what I'm going to do with/to it, but that's pretty inspirational
If you plan on using the +/-12V lines then keep your mods minimal and/or upgrade the 78L12 and 79L12 to 78M12 and 79M12. _________________ JacobWatters.com
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