Korg Delta

Korg delta string synthesizer
Korg Delta

The Korg Delta (or DL-50) is a string synth/polysynth hybrid from the late 1970s to early 80s, from the time when every synth company was focusing on those.  I’ve got an Arp Omni 2 and Roland RS-09 of the same era here in the workshop right now and the Delta is my favorite of all three, even just based on its string sounds (to be fair, the RS doesn’t have a “synth” section).   Continue reading “Korg Delta”

Sequential Circuits Drumtraks

This was for producer Gino Wong of ReRed Recording, but I was excited to get it working for my own reasons, so that I could sample the drum sounds into my Electribe. Once I did get it working, I discovered that the SCI Drumtraks is super easy and fun to make beats on! I didn’t know this before, but the sounds on here are not synthesized, but rather are low-fi samples each on their own EPROM. Continue reading “Sequential Circuits Drumtraks”

Moog Rogue

Moog "The Rogue"
Moog Rogue

The Moog Rogue is very, very similar to the Moog MG-1.  It has pretty much the same internal design in the synth section, but the designers made some questionable choices about which parameters to allow control of– so unlike the MG-1, both oscillators on the Rogue have to have the same waveform, and be in the same octave. Continue reading “Moog Rogue”

Moog / Realistic MG-1

 I love these little Radioshack Moogs! I have a MG-1 of my own that I overhauled and heavily modded a while ago, and I’m always happy to bring another into the shop. They are so simple and there are only a couple parts that are hard to find– the sliders, the switches, and the MM5823 frequency divider ICs. This MG-1 was not in too bad shape, and the foam under the panel had mostly been removed already, but had one of the three divider ICs not working.
Service Tips
If you have several octaves of a handful of notes not playing, the MM5823 frequency divider ICs are the culprit.  I found a clever replacement solution from Flatkeys, a company in the UK— a little SMD board that fits right into the place where the original 14-pin DIP IC went.
There was also a slider with a broken wiper, but I couldn’t find any sliders of that type with the right value (10K) anywhere on the internet, so I bought a 2M one from Syntaur, took both apart and swapped out the resistive strips– as I was doing it, I was telling myself, “I am doing a ridiculous thing,” but it worked.
 
Work done: replaced all electrolytic capacitors, cleaned switches, cleaned and lubricated sliders, replaced MM5823 IC, replaced one bad slider, added 1/4″ output jack