EML 101 and 100 1 V/Octave Mod PCBs and Kits now available

EML-101/100 1 V/Octave Mod kit installed

By “somewhat popular” demand (having been asked for the schematics “several” times) we have made a PCB and kit available for the circuit we use to add 1V/Octave scaled input to the ElectroComp EML-100 and EML-101 synthesizers.

The EMLs use between 1.2 V/Octave and 1.4 V/Octave (varying from one unit to another) with an offset of between 4.2V and 4.6V. Our board allows you to feed in conventional one volt per octave control voltage from another synth, controller keyboard, sequencer, etc. and scales it up so that the EML’s second-voice oscillators (Oscillators 3 and 4) can track it. Using a sequencer especially opens up amazing possibilities for this already very powerful synth!

Our original version of this circuit just performed the summing and amplification and required the installation of a new external switch to turn the mod on and off. Our new version uses a multiplexer to automatically perform this switching task when a plug is inserted in the CV input jack. This means that it can be completely invisible– no hole needs to be drilled, and the synth functions 100% as original when nothing is plugged in.

The mod can be used on both versions of the EML-101. On the later version that has a “Sequencer” jack, the Sequencer jack becomes the 1V/Octave input, and on the earlier version, another jack can be selected to be the new 1V/Octave input (we use CM3).

We are looking for someone to help us take photos of the installation in an EML-100 in exchange for a free PCB or kit so if you have a 100 and are interested in the mod, please get in touch!

The PCB will come with schematics, bill of materials and detailed installation and tuning instructions with lots of full color photos. The kit will come with all of the above plus all required parts and the jack already partially wired (because this is probably the thing people are most likely to mess up!)

The PCB and kit can be ordered here!

ARP Avatar – Retroaktiv patch bay kit installation and the vintage synth modding controversy

ARP Avatar with Retroaktiv “Modular Patch Bay Kit”

This was a pretty big mod project that Darian finished a few weeks ago on an ARP Avatar, the ARP guitar synth which is mostly just a keyboardless Odyssey with a bunch of guitar-processing junk that no one cares about. That’s just a fact. Anyway, several years ago New England Analog developed this kit to break out a lot of the CV input points and modulation sources of the synth’s architecture to 1/8″ jacks mounted on a single long PCB, and now that New England Analog has closed, a new version of the kit is available from Retroaktiv. Continue reading “ARP Avatar – Retroaktiv patch bay kit installation and the vintage synth modding controversy”

Sequential Circuits Prophet 600 – Gligli Upgrade

Sequential Circuits Prophet 600
Sequential Circuits Prophet 600

This Prophet 600 was brought in for a Gligli P600FW upgrade, which is a CPU/firmware upgrade using a Teensy ++ microcontroller board. It offers improved resolution for all parameters (128 values instead of like, 15 or 7!), a new LFO just for vibrato, arpeggiator MIDI sync and more, which you can read about here.┬áThe firmware is generously offered for free by the developer and in order to install it, we procure a Teensy 2++ board, do some modification to the Teensy, flash the firmware onto via USB, and install it in the Prophet 600 in place of the original Z80 CPU. We can do this mod for only about $100 including parts. Continue reading “Sequential Circuits Prophet 600 – Gligli Upgrade”

“Kiwi-8P” Roland JX-8P Upgrade (and a Kiwi 106)

"Kiwi 8P" upgraded Roland JX-8P
“Kiwi 8P” upgraded Roland JX-8P

I did the Kiwi 8P upgrade on this Roland JX-8P this week and just by coincidence did a Kiwi 106 just last week as well. These are very deep and powerful synth upgrades designed by a New Zealand-based company called Kiwitechnics, and they have similar ones available for a few other 80s polysynths. Continue reading ““Kiwi-8P” Roland JX-8P Upgrade (and a Kiwi 106)”

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”

Sequential Circuits Pro One – CPU upgrade and MIDI retrofit

sequential circuits pro one synthesizer
Sequential Circuits Pro One

When we got this Pro One it was acting insane: keyboard playing only one note and/or pitch sliding upwards, loud bursts of noise, weird envelope/triggering behaviors. This synth is unusual for its vintage (early 1980s) in that much of the control voltage for the analog circuitry is generated by a digital CPU, which was hot enough that it burned Darian’s finger when he happened to touch it, badly enough that he still has a blister a week later! So clearly the CPU was bad– and further testing confirmed it. Continue reading “Sequential Circuits Pro One – CPU upgrade and MIDI retrofit”

Moog Werkstatt – custom mod project

modified Moog Werkstatt
Modified Moog Werkstatt

I just finished up some intense custom mods on this Moog Werkstatt. I packed in a bunch of cool goodies and the case of this little synth is now totally at capacity. It even bulges a little bit, and it feels noticeably heavier. It sounds amazing if I do say so myself. Continue reading “Moog Werkstatt – custom mod project”