Month: August 2017

Roland Juno 106 (#7) – this is New Jersey

Roland Juno 106
Roland Juno 106

Sold! Now FOR SALE in our Reverb shop!

I bought this Juno from a guy named Mike in South Jersey, with a shaved head and a gold chain. I met up with him at his garage studio behind a roller rink, where the Juno had been used for over 25 years by musicians providing live accompaniment for the roller skaters. Now the music is performed by two “old cowboys” (his words) on two Hammond console organs. I also met Mike’s overweight English bulldog, who he introduced to me as his girlfriend. I think her name was Bethany. Continue reading “Roland Juno 106 (#7) – this is New Jersey”

Desoldering Tutorial: Tools, Techniques and Helpful Tips

the frikkin desoldering gauntlet

I would say that desoldering is much harder than soldering. It took me a couple weeks to get good at soldering and several years to get good at desoldering, partly because I didn’t used to do it as often when I first got into electronics, just building circuits from kit PCBs and schematics. Working on old synths though, I have to desolder all kinds of things constantly from different kinds of boards and have refined my techniques pretty well, so I thought I’d share some of what I’ve learned here. Continue reading “Desoldering Tutorial: Tools, Techniques and Helpful Tips”

Korg Electribe ESX-1, continued / updated Nov. 2019

11/3/2019: OK, I have yet another update on this!

Unfortunately, about 2 years after I implemented the fix I describe below (debouncing capacitors for each pot, plus a shield) the issue came back!
I wanted to take a closer look through the circuitry with my oscilloscope but did not yet get a chance to because when I opened it up, the issue went away. So I just did my best guess of what might help and packed it up yet again.

I had a good idea of what might help, because thinking more about the symptoms had led me to a stronger idea of what might actually be the issue.

There are really two symptoms:
1. constant random jittering of pot values, which is what people usually focus on
2. the pots can NOT be turned down to 0,  the minimum value anything can reach at full counterclockwise position is 2 or 3 for me usually. Continue reading “Korg Electribe ESX-1, continued / updated Nov. 2019”

Korg MonoPoly

Korg MonoPoly
Korg MonoPoly

This MonoPoly had the worst kind of problem when it arrived: a very intermittent problem. It had a tendency to fade out randomly, and then randomly fade back in. The first day it was here, we ran it for 12 hours continuously without any such incident. It took us a long time to figure out what was going on because it was hard to get it to replicate the problem. Continue reading “Korg MonoPoly”

EML ElectroComp 101 – 1 volt per octave conversion mod

Update, 8/2019: we are now selling PCBS and kitsf that make it easy to install this mod! Click here for details.

This is a really fun synth! EML was a lesser-known American synth company competing with Moog and ARP during the 1970s and made some unique instruments. The EML-101 is a semi-modular duophonic synth similar in structure to the ARP 2600 and very unique and powerful. The bulk of our work on this involved designing and installing a circuit that allows the synth to accept standard 1 volt per octave-scaled CV via its “SEQ” input, as its oscillators have an unusual scale of 1.4 V/octave with a 4.6-volt DC offset. Continue reading “EML ElectroComp 101 – 1 volt per octave conversion mod”