Christmas Project #1 - MIDI to CV Converter

Using this helpful article, I've modified the provided code and added a gate output and R2R ladder to get the schematic on the left. The construction is all wire-wrap at this point. After a little more wrapping and the addition of a nice enclosure, I should have a sweet controller interface.

New Project: Inverter SVF

While I won't say my first attempt at a state variable filter (SVF) was a complete failure (I think I need to switch the linear pots to log pots to get a useful response), I'd like to try this filter.

Top Octave Module

I decided to take the top octave chip I found and expose all of the pins with banana jacks rather than insert it into a self-contained unit. With a "utility clock module" I'm putting together, I figure I'll have enough flexibility to produce what I need. I think the sequencing may be a little awkward, though.

Completed Power Supply

Here is the completed power supply. No switch. No LEDs. Just an AC mains cord and 4 jacks: ground, +/- 12V and +5V. Here's to dual supply circuit goodness!

Link of the Day - 23 Aug 2010

I came across the Melloman project a couple of years ago. It has inspired me to repatriate a few orphaned tape players from my parents' house and a couple that I purchased at the MIT Flea for what seems like way too much money and create a Moog Taurus-like foot pedal synth. "Where will the foot pedals come from?" you ask. That's where the old Wurlitzer comes into play. I will marry the Walkmen and the foot pedals to form the most stupendous Mellotaurus (tm).

Project #4 - Fancy Noise Generator

A few months ago I found a simple, two transistor, noise generator that I figured I could knock out in a few minutes one day. Well, I never got around to building it. Then I came across Ray's "Pink Enough for Me" noise generator at MFOS. I think I will devote some time to put this one together. It seems to have 3x the parts necessary, though.

Then in an effort to find a picture to make the post a little less mind numbing I stumbled across this noise generator at Synths 'R Us. Lots of good schematics at this site.

Link of the Day - 23 Aug 2010

This site has links to many Roland filter schematics. Many of them use that pesky CA3080. I fear I may never use the few that I have until I find "the perfect" schematic.

I was very anti-OTA for a while. I've come to accept them to some degree. Although I'm still not convinced buying a LM13700 for a $1.75 a piece is worth it.

Project #3 - Dual Power Supply

This project didn't require too much hand-crafting. I took the box that my Big Muff Pi (the old version with the black case) came in and a wall-wart-like dual power supply (+/- 12V & 5V) and put them together with some banana plug sockets and, voila, she is complete.

Well, technically not complete. I still need to add the AC power cord and some labels for the 3 voltages (I did manage to get the ground labeled).

Acquiring a reliable dual power supply has been quite a challenge. For the longest time I sought circuits that didn't require such a supply. I also attempted to hack together one that didn't quite work. I've also purchased a number of dual supplies at the MIT Flea that require a tad more TLC/useful package to help.

Project #2

Simple VCF found on electro-music.com. I like how the voltage control doesn't require an OTA (I'd like to save the precious few I've salvaged).

And right after I say this, I see on MFOS that there are some simple schematics from the WP-20 Synth.

While I have yet to breadboard it, the circuit looks simple enough. Most of the VCF schematics I've found have been like this from Scott Stites's site. I'm thinking the op-amp with the diodes in its feedback path could be extracted and used almost by itself to do some waveshaping. We shall see.

Project #1

ARP Ring Modulator:

http://www.simple-answer.com/ARPring.gif

Found via: http://www.simple-answer.com/DIY.html

Looks like a simple enough build. Although, it may require some rectification on the inputs to ensure the NAND gates don't go all squonky with AC action.