I thought it was a good idea to incorporate a matrix patching system, similar to that used by EMS for the revered VCS3 and subsequent Synthis, into my Eurorack modular system and thus be able to explore new and different patching methods. It is only after I started the project that I discovered that the concept of a stand-alone patch matrix to use with modular equipment is not exactly new...
Such a patching system pushes one to think out his patches differently and also gives more easily "happy accidents". Also, this system let's me prepatch a series of modules to the matrix and I can change the patch very quickly just by switching the pins, by adjusting a few settings on the modules and not having to unpatch and repatch every single module... quite a time saver.
Attenuator banks were added, that can be patched in freely on in- and outputs of the matrix.
This comes in handy when some signals coming from modules need to be attenuated (of course if there is no output attenuator installed on the module for that signal), same thing for the signals that go back to unattenuated inputs of the modules.
50K Lin pots were used for attenuation of CV signals and 50K Log pots for audio signals.
Attenuators are stand-alone, have input and output patchpoints so they can be put into the signal path or not.
The system was intentionally designed unbuffered, (original matrixes on the EMS instruments were also unbuffered) to retain it's share of unpredictability and joyful weirdness.
Installation of a buffering, as described by Graham Hinton , was an option but the precision and stability that a buffered system offers is not really justified or necessary for the type of work I have in mind.
Also background noise and crosstalk are kept to acceptable level without any active circuitry.
Of course, there is obviously some crosstalk of adjacent signals...it all depends on the nature and amplitude of the signals and this problem can easily be addressed by patching otherwise. This has it's charm and I certainly can live with that !
Simple contacting pins are used (the blue ones). Pins with diodes can be used (the red ones), but these block one half of the period of bipolar signals. Still, diode pins can provide some interesting results for specific applications and can prevent signals to go where they should not go within the matrix.
Panels were designed with Front Panel Designer and manufactured by Schaeffer AG
I chose to split up the panels in three parts :
1 panel for inputs with attenuator bank and 1 panel for outputs with attenuator bank.
1 panel for the main matrix and a smaller 10x10 matrix as "pin park"
The three together are sized 168HP wide and 6U high, so that I will be able to fit it perfectly in the custom cabinet I plan building in the future for my Eurorack system.
All inputs and outputs of the matrix are wired to Sub-D 37 connectors (36 signals and one common "ground" per connector), so are all the inputs and outputs on the respective panels, this to ease up maintenance and thus not having to remove all three panels at the same time whenever maintenance would be needed.
Assignment of signals to the matrix rows and columns is totally free, but still, I was inspired by the EMS matrix assignments and adapted these to the in my system available modules, i.e. transcription of patches from EMS "dopesheets" to my system is very fast and easy.
Buttons for the pots were purchased from Banzaï Music and are the following type : Rotrik Knob SM-29
In use the FriFri deluxe is a breeze, its clear and logical design makes for effortless identification of sources and destinations. Readability of the patch is quite good. The ergonomics are far from bad, even with all inputs and outputs fully patched, the matrix remains accessible. Though, it is sometimes difficult to remove pins that are inserted one next to the other as the spacing between contact points is very tight, but one gets used to this quite easily.
Usage proved that the best location to place it in a "large" system is at the bottom, horizontally or on a slight angle; or, even better, vertically in the highest position in the cabinet. This placement prevents any patchcords from "hanging" over the matrix. Until the custom cabinet for my Eurorack modular is finished, I chose to place the FriFri deluxe central in my system.
Even if this system is far from perfect, I love it, it does perfectly what I designed it for and what I expected it to do. I learned to work around or with its inherent flaws or quirks and results are very often satisfactory, different from the patches produced with the "classical" patching method.
I've uploaded a set of patches on my Soundcloud page which illustrate the combination of the FriFri Deluxe patch matrix with a selection of Eurorack modules : The Synthi experiment
- a switch to enable/disable interpolation
- a switch to go from Morphing Mode to Phase Shift Mode
- attenuators for the X, Y and Z CV inputs to control the depth of the respective modulation