DIY SynthesizersInterfaces and sub-systemsDIY Audio Efects
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General description
Gallery of ASM1  pictures
Sounds of the ASM-1X



All modules are connected to the matrix It is the heart of the ASM-1X. The matrix patch and pins come from an old calibration rack used for planes. It is a Ghielmetti sized 32x11, 90% filled with goldplated 2mm diodes pins!

Originaly it was a (15+17) rows for 11 columns, but i have splited it , changing for (15x11) + (17x11) with some common rows.The matrix was easy to open, Swiss made! I have cutted vertical contacts on middle, and put connectors for columns of the second half. I have prewired direct connections betweens rows, columns and buffers. The matrix is screwed to a structure made of aluminium corners who shield it.The synth has been builded all around by adding pcb and aluminium structures.

.Matrix buffering schematics (gif)

  • Upper matrix is for signal ("audio") , Lower for controls (CV...).
  • Inputs (Rows = modules output)  are buffered by a classic inverter stage at unity gain.
  • Outputs (Columns = modules input) are connected to a classic summing stage (g=1). Connected pins contain input resistors.

Pins Modification

For an analog summing matrix patch, the pin must contain resitors, not diode. Using a razor blade,cms solder iron, and lot of patience, it was finaly possible to replace the diode by a little CMS resitor without destroying the pin. Here is the method i use:

    1. remove the plastic ( blue or red on my pins)with cutting-nippers cut the diode side of the pin approx 0,5cm from top...Destroy the diode, It doesn't matter.
    2. remove with thin pliers,cutter or razor blade, remaining pieces of  the diode and the metal around it, until you can see the black plastic isolant and the solder point of the diode.
    3. After a good cleaning of the pin, an isolation test of the body and top of pin, solder one side of  a 10k CMS resistor.Now using a little thermotube,isolate the cms and the solder, exepted  the free side of the resistor.
    4. Connect a thin (classic)resistor leg wire from the body of the pin to the cms resistor and test with the ohmmeter...
    5. Finaly encapsulate the assembly with a kind of sealing-wax .Not perfect looking , but works rigth and can be repaired.


© Marc BAREILLE 2002