Alright, I know all posts so far have been about building my SYS-700 modules, but I wanted to take a moment to share my thoughts about some of the storebought modules that have made their ways into my racks. But first an update on LFO 1’s troubleshooting work.
LFO 1 turned out to have a bad copper pad on the board after soldering, removing and resoldering a resistor in the signal change for the Frequency pot. Some excellent suggestions from the Muff forums lead me to run a small hookup wire between the header on the board and this pad, which restored functionality to the Frequency pot. There are still some remaining calibration issues that I’m still working through:
The SAW waveform is supposed to be adjusted so that its bottom-most point is at 0V, but I cannot get the bottom voltage to be greater than about -0.45V. Pharmasonic has suggested replacing a 100k resistor on the board with a 120k or 130k resistor instead.
The Frequency pot has 2 trims associated with it: a FREQ and a WIDTH trim. Calibration instructions say to set the Frequency pot to “10” (hertz) and calibrate the FREQ trim until the LFO is outputing a signal at that rate, then adjust the Frequency pot to “0.2” and adjust the WIDTH trim until the LFO is outputting a signal at that rate, then continue to adjust these two trims while setting those frequencies until things normalize out. I am not able to adjust the WIDTH trim enough to arrive at a 0.2hz frequency, as the TRIM maxxes out at about 2.5hz. Pharmasonic hasn’t suggested a solution to this beyond checking the resistors again to look for something that is not correct. I’ll probably do this one more time to humor them and then ask what resistors are inline in the frequency part of the project and try replacing things with different values to see what happens.
Other than these two issues, LFO 1 now works as expected. I expect to start in on troubleshooting LFO 2 soon, and look forward to getting the VCF’s working next. The last ‘todo’ for me for this project this week is to calibrate the VCA’s and make sure they’re working as expected. They’ve been sitting in the rack looking ‘done’ but have not actually been calibrated so there could still be things wrong with them.
Storebought modules
While building this project has been fun and quite the learning experience, I’ve also been buying storebought modules at a fairly rapid rate. Some of these were for utilility and pretty much needed to build the SYS-700 modules, but certainly not all of them. I’ve currently purchased 11 modules so far:
The Utilities
- 4MS Row Power 30— supplies power to the rack.
- 2hp MIDI— provides a small but fairly flexible MIDI-to-CV solution
- David Jones O’Tool— an oscilloscope/level meter/voltmeter that has been pretty critical in the process of testing and calibrating modules
- Erica Synths Pico Out— a small and simple output amp which adjust Eurorack signal levels back to ‘normal’ levels, and also sports a headphone output
- Eric Synths Pico Input— a small and simple input amplifier that adjusts incoming signals to Eurorack signal levels.
- Mutable Instruments Shades— 3 channels of signal attenuation or mixing. This was needed to provide 10V CV signals to modules for testing purposes and hasn’t been too heavily used for other purposes yet.
The Fun (Non-utility) modules
- Mutable Instruments Marbles— this random sequencer is pretty much the source of all note and gate data in my racks currently. It outputs 3 gate signals and 4 CV signals that can be used for pitch control of pitched modules, and has features to loop signals so they’re not totally random every time. Finally, the module also includes a quantizer that can take those random CV values and snap them to semitones and even custom scales. This device has saved me from constantly having to plug my rack into my laptop to provide note data, and was the first thing a salesperson recommended to me when I walked into a synth shop and told them I wanted something that will make “generative music”. This thing has literally run by itself for days on end already, with me just sitting and listening to it and adjust knobs once in a while.
- Mutable Instruments Plaits— this was an upsell from when I bought Marbles. The salesperson suggested it as an easy “starter” sound source, as it included several oscillator models as well as including built in VCA’s and LPG’s, which would allow me to “get started” making noise without having to include dedicated modules for those purposes. While certainly flexible and having an impressive depth of sounds, I’m finding most of the sounds it produces are not to my liking and wonder what it will ultimately be used for. While good for the money, this may not be my “go-to” oscillator module for that many purposes.
- Mutable Instruments Tides – This flexible module provides a lot of features at the cost of size. It can act as an LFO, VCO, AD signal generated, and AR signal generator, plus has some fun jitter and waveshaping features. The only drawback I see at this point is its size makes it possible to replace it with a dedicated LFO and envelope generator in the same amount of space, and then you could use them both at the same time. Many folks discuss how this module ends up getting used in their racks, and it seems to fill different niches for different people. As a VCO, it has a very nice “flute”-esque triangle wave sound.
- Mutable Instruments Stages – This is one of my newest modules that I’m still trying to come to grips with. It is another “flexible” device that can act as an envelope generator, a series of LFO’s, a sequencer, or combinations thereof. So far I haven’t gotten much out of it, but also haven’t put much effort into understanding it yet. I expect it will eventually be a heavily used module once I’ve got it all figured out. This module is a actually a “clone” by Momo Modular, which has the same size as the original module, but cost about $120 less and came with a cooler looking black panel.
- Momo Modular Threshold – This is a clone of the Mutable Instruments Edges module, which is a “quad chiptune audio generator.” This is apparently one of Mutable’s earlier modules that are no longer sold, but are still offered in various packages from other 3rd party builders (such as Momo). This thing makes great NES/digital squarewave sounds and, while still new in the rack, promises many great things.
- Make Noise Dynamix – A LPG that doesn’t use vactrols, which I grabbed used from a local seller at a good price. It has a very fast response rate and doesn’t sound all that much like a “classic” LPG, but is still very usable as a VCA and has some nice but subtle tonal qualities. I’m thinking I will probably like the Make Noise Optomix better, which does use vactrols and is otherwise mechanically similar to this module. I plan to get an Optomix soon and will then decide whether I need both it and the Dynamix, or whether I can let one or the other go.