NOTE:
I have modified the design and added a buffer to the S-Trigger to V-Trigger converter and circuitry to allow you to pick an output voltage level using a zener diode. Please contact me if you want to order a PCB. I have not yet ordered a stock of the new design.
That said, I have lots of the old through hole design available.
PLEASE READ:
I recently noticed some significant noise when the voltage gate was at 0 volts. The simplest fix is to use a TL074 op-amp or an LM148 or LM248, or LM348, in place of the TL084. The 084 simply became unstable in this circuit. The LM148, LM248, and LM348 op-amps are simply four 741s in a quad package. The difference between the three is the 148 is MIL Spec, the 248 is for less harsh industrial use, and the 348 is more commercial general purpose. I like the 741 idea and am using an LM348 in my converter. The TL074s seem to give a faster rise time than the 148-348s, but I doubt it’s a problem.
One last important caveat. When I tried several different Texas Instrument TL074s, the same op-amp section of the 4 op-amps had the instability problem on every op-amp I tried. The other three op-amp sections on all the op-amps tested were fine. I also have some STI TL074s and these work without problems. I have no clue why the TI chips have this problem but it was absolutely consistent on each one I tried. The same op-amp section on every chip. Weird.
Buy the PCB:
DOCUMENTS:
FUNCTION:
These PCBs are made to convert back and forth between S-Triggers/Gates and Voltage Triggers/Gates. It’s a really simple circuit, and works great. The 12X4 was made to compliment the original Sequencer. The current design has an option to build on the PCB S-Trigger I/O or Voltage Trigger I/O.
USE:
Inputs/Outputs:
8X8:
- 8 Each S-Trigger inputs
- 8 Each Voltage Trigger inputs
- 8 Each S-Trigger outputs
- 8 Each Voltage Trigger outputs
12X4 (or 4X12, I don’t think it matters)
- 4 Each Voltage Trigger inputs
- 12 Each S-Trigger inputs
- 4 Each S-Trigger outputs
- 12 Each Voltage trigger outputs
GENERAL CONNECTIONS:
Simple, connect the trigger you want to convert to the appropriate input and connect the corresponding output to your device. Remember, you CAN’T simply connect multiple Voltage Triggers together in a multiple. You have to sum them. However, you can connect all the S-Triggers you want in parallel in a multiple as a logical OR function. I really like S-Triggers.
Resistors:
This module was originally built with carbon core, 5% resistors with one or two 1% metal film resistors. So, you have a wide range of options here. I recommend using 1% tolerance, metal film resistors everywhere.
Capacitors:
There are probably a billion different ceramic capacitors at a place like Mouser. Pick a capacitor that can fit the hole easily, typically 0.1 inch on centers.
Pick good quality electrolytics where designated.
Transistors:
Any good small signal transistor works.
Diodes:
Nothing special, 1N4148s are fine.
Jacks:
For the panel I laid out, a good 3.5 mm or 1/8 inch jack will work. I use the Switchcraft 42A Tini-Jax true 1/8 inch jack. These are switched jacks and they work with 1/8 inch plugs and 3.5 mm plugs.
BUILD NOTES:
Soldering:
I assume you know the basics of soldering. I like to insert the low lying parts first, like resistors, diodes, etc. After these, I install the IC sockets. Next capacitors, transistors, connectors. Use a good solder, either an organic flux, which you should wash regularly, or a no-wash flux.
Take a break every so often, wash off the flux if you are using a flux which required cleaning. Double and triple check orientations, pins, and solder joints.
Power Supply Regulation/Filtering:
Only the S-Trigger to Voltage Trigger needs power, +12 volts.
COMPONENT PLACEMENT:
Mounting:
This PCB has four holes to allow flexible mounting configurations.
PANEL NOTES:
There is nothing too special. I suggest using connectors on the PCB and jacks on the flying wires. The spacing and holes are setup for Alpha 16 mm or 12 mm pots. The jack holes are 0.25 inch in diameter.