<a href="http://www.casperelectronics.com/images/finishedpieces/MiniModular/S3600004.JPG"><img src="http://www.casperelectronics.com/images/finishedpieces/MiniModular/_S3600004.JPG" width="400" height="534" alt="" title=""  /></a>This piece is an analog modular synthesizer which I built from scratch over the past year. If you're not familiar with what a modular synth is, click <a href="http://en.wikipedia.org/wiki/Modular_synthesizer">here</a>.<br>
MODULES:<br>
1x 16 step CV sequencer
4x VCO
2x noise source
2x VCF
3x VCA
2x LFO
2x AR envelope
1x ADSR envelope
2x ring mod
1x Attenuated mixer
4x CV mixer/inverter
<a href="http://www.casperelectronics.com/images/finishedpieces/MiniModular/S3600011.JPG"><img src="http://www.casperelectronics.com/images/finishedpieces/MiniModular/_S3600011.JPG" width="400" height="534" alt="" title=""  /></a>
This photo shows the system (minus the bottom panel) interfaced with the <a href="http://www.casperelectronics.com/finished-pieces/sequencers/step-sequencer/">step sequencer</a><br></p>
The modules are based almost entirely on circuits designed by <a href="http://www.paia.com/p9700s.asp">Paia electronics</a> and <a href="http://www.musicfromouterspace.com/">Ray Wilson</a>. Ray Wilson has a fantastic site called <a href="http://www.musicfromouterspace.com/">Music From Outer Space</a> which I can't say enough good things about. The site is an invaluable resource for the synth building enthusiast. Another good source of synth PCBs is Ken Stone's <a href="http://www.cgs.synth.net/">CGS synth</a> page. He has a larger variety of pcbs than Ray, but his documentation isn't nearly as complete. <br>
<p><strong><u>LAYOUT</u></strong><br />
The system is broken into three cabinets:</p>
top- 16 step CV sequencer.<br />
middle- modified Sound Lab Mini Synth<br />
bottom- paia and custom modules <br />
Below is a list of the modules with comments on each:<br>
<a href="http://www.casperelectronics.com/images/finishedpieces/MiniModular/topcabinet.JPG"><img src="http://www.casperelectronics.com/images/finishedpieces/MiniModular/_topcabinet.JPG" width="400" height="300" alt="" title=""  /></a>
Details on the sequencer can be found <a href="http://www.musicfromouterspace.com/analogsynth/SEQ16_2006/SEQ16_2006.php">here</a>.
This is Ray Wilson's design and was built using the circuit board sold through his website. 
My favorite feature of the design is that the run sequence can be adjusted in a variety of ways. For instance you can set it to bounce back and forth or set it to random mode.<br>
My only regret with this part is that I chose not to include fine tune adjustments for each step.<br>
This makes it very difficult to program precise musical sequences. it's still a very useful module though.
<a href="http://www.casperelectronics.com/images/finishedpieces/MiniModular/middlecabinet.JPG"><img src="http://www.casperelectronics.com/images/finishedpieces/MiniModular/_middlecabinet.JPG" width="400" height="300" alt="" title=""  /></a>
Modules from left to right:<br>

This cabinet is basically a heavily modified <a href="http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/soundlab.html">SoundLabMiniSynth </a>. If you aren't familiar with the SoundLab, you should go to Ray Wilsons site and read up on it. It's a simple but very powerful little device and is a great project for the newbie synth builder.<br>
What I've done here is take the SoundLab design and make it completely modular. There are details on his site on how to do this. Below is a list of modifications and additions.<br>
- fine tune pitch controls for each VCO <br>
- cross modulation switch <br>
- ad/dc modulation switch to VCO #1 <br>
- modulation input adjustment to VCO #1 <br>
- saw and square outputs to VCO #2 <br>
- LP and BP outputs to VCF<br>
- added 2nd LFO. Identical to the original SoundLab LFO. <br>
- added Sample and hold module. <a href="http://www.musicfromouterspace.com/analogsynth/singlechipsampleandhold/singlechipsampleandhold.html">Here's</a> the schematic. I highly recommend adding this circuit to your design if you build a SoundLab.<br>
-added ring mod. <a href="http://www.musicfromouterspace.com/analogsynth/RingModulator/RingModulator.html">Schematic</a>.
This is an awesome and very simple ring mod. I highly HIGHLY recommend this circuit.</p>
<p><strong><u>NOTES:</u></strong><br />
This thing is quirky all over the place. The VCAs are noisy, the filter warbles when the resonance is all the way up and the noise output only worked for a day. But overall it's a real beast and makes some amazing sounds. <br>
I've played with a few other sound labs that friends built based on the original normalized layout.
I greatly prefer the modularized design and think it allows for a lot more experimentation and potential for further developement.<br>
If you do decide to build a modular SoundLab, I strongly recommend that you include input adjustment for many of the parameters. I wish I had installed more of these. <br>
<a href="http://www.musicfromouterspace.com/analogsynth/singlechipsampleandhold/singlechipsampleandhold.html">Sample and hold</a> and <a href="http://www.musicfromouterspace.com/analogsynth/RingModulator/RingModulator.html">ring mod</a> are a must!</p>
<a href="http://www.casperelectronics.com/images/finishedpieces/MiniModular/bottomcabinet.JPG"><img src="http://www.casperelectronics.com/images/finishedpieces/MiniModular/_bottomcabinet.JPG" width="400" height="300" alt="" title=""  /></a>
This cabinet is made up of modules from a <a href="http://www.paia.com/p9700s.asp">Paia 9700 synth</a>, a few simple Ray Wilson designs and a VCF using the SSM2044 IC.
Paia makes a decent modular synth that you can buy in kit form called the 9700. It's a pretty clever design and they figured out how to cram a whole lot into a small package. The problem I have with it is that I think the normalizing scheme is a little to clever for it's own good and it ultimately results in a confusing layout. I decided to reconfigure the layout of the VCO and VCA modules and include them in the synth. It ended up being a little more complicated than I thought it would be and I had to spend a lot of time studying the schematics. I made a few modifications as well while I was at it. </p>
- adjusted VCOs for wider pitch range<br>
- fine tune adjustments to both VCOs<br>
- pulse width modulation inputs for both VCOs<br>
- added output amount adjustment to ADSR 





The core of the modular system is the wildly popular (in the synth DIY scene at least) <a href="http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/soundlab.html">Sound Lab Mini Synth</a>. Details on the SoundLab can be found <a href="http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/soundlab.html">here</a>




 about 2 years ago in the summer of 06' I decided I was going to build a modular synthesizer. If you're not familiar with what a modular synth is, click <a href="http://en.wikipedia.org/wiki/Modular_synthesizer">here</a>. I started collecting circuit boards from <a href="http://www.cgs.synth.net/">Ken Stone</a> and <a href="http://www.musicfromouterspace.com/">Ray Wilson</a>. Both of these guys have amazing web sites and sell a variety of synth circuits. Ray Wilsons site <a href="http://www.musicfromouterspace.com/">Music From Outer Space</a> is especially helpful as he provides VERY in depth instructions on how to build his circuit designs. <br>
There have been many stages to building this piece (building the housing, designing faceplates, ordering materials). It has been VERY time consuming, but is ultimately one of the most exciting and rewarding projects I have taken on to date. <br>
The core of this piece is the wildly popular (in the synth DIY scene at least) <a href="http://www.musicfromouterspace.com/analogsynth/SOUNDLABMINISYNTH/soundlab.html">Sound Lab Mini Synth</a>. This is Ray Wilson's design and is sold on his <a href="http://www.musicfromouterspace.com/">website</a>. This project is simple enough for the circuit building newbie to tackle and can produce a wide range of rich sounds and effects. There are also endless ways that the design can be easily modified and upgraded.<br> Expect to spend at least $100 if you build this project. It's not super cheap, but for what it does that's a steal.


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