1. Introduction

  Building an Integrated Analog Electronic Synthesizer, how's that for a catchy title.  Maybe I'll think of something better later.  If you don't know what I'm talking about, the short answer is something along the lines of the Roland Jupiter-8, Oberheim OB-8 and other similar lines of analog synthesizers.  Want the long answer?  Well, just follow this blog and you should get a pretty good idea.

  First a little background.  Why would I want to build such a thing?  Growing up in the 80's I've always been fascinated by synthesizers, but wasn't able to own one.  Fast forward decade or two, after getting a degree in Computer Engineering (combination of electrical engineering and software engineering) and settling into a decent EE career, I decided to finally satisfy my craving for a synth.  Knew almost nothing about synthesis and the history of the various types of music synths.  I simply dove in and purchased a brand spanking new Kurzweil K2600X, a decision based mostly on naive reaction to rave reviews.

  I noodled around with it a few years and while it's certainly a fantastic instrument, I never found the sound I was hearing in my head.  So I started doing some more research, initially to better understand the workings of the K2600, but eventually my search took me through the history of the development of the synthesizer and the various types of synthesis employed as the technology evolved.  I finally came to the realization that the sound I was looking for was created by analog subtractive synthesis, mainly using the synths I mentioned in the first paragraph.

  OK, cool, I'll just pick up a used Jupiter 8 (they have long been out of production).  Oops, not so fast.  Turns out I was about 2 years to late, Jupiters had seen a resurgence in popularity and prices had skyrocketed, at this point apparently fetching $6000-$8000.  Oberheims were more reasonable for around $2500-$3500.  The K2600 on the other hand had depreciated substantially from what I originally paid for it, otherwise I might have sold it and put the cash towards another synth.  But as it was, I just didn't see getting much value out of selling it and felt it would still be nice to have around.

  So what to do?  I could have bit the bullet and bought an Oberheim, which I almost did a few times, but during my research I came across service manuals for these synths that included quite a bit of detail.  Being the curious sort and of course having an EE background, I started studying these more closely and thought hmm, what if I could just build one?

  The goal: A synth with an architecture similar to the Jupiter 8 and OB-8, all analog signal path, 8 voice polyphonic, 2 oscillators per voice, low pass filter, 2 envelope generators, playable from a midi keyboard (no built-in keyboard).  The designs of the Jupiter and OB-8 centered around several IC's that are now obsolete and I wasn't terribly concerned with being able to save and recall patches, so I quickly rejected the idea of building a "clone" and set off to create something that met my goal.  And so the journey began....