Bill and Will's Synth
Moog Transistor Matching Tester Construction

December 2009 -

To build the YUSynth EMS Diode Ladder Filter, we want to use matched transistors. We looked up transistor matching on the web and came across this thread on the electro-music.com forum.

Using the transistor tester schematic, we developed a layout for it on a MUUB3 which has the handy MOTM standard power connection and the little breadboard area - perfect.  You can see how we used it by clicking here.

Background - The MOOG Schematic

Here's the Schematic Diagram from the Mini Moog manual - click on the image for a larger version.  It's set up for 10V power supply and it has a mistake in the PNP diagram.

Here's the adaption for 15V and our correction of the PNP diagram.

Here's how we laid it out on the MUUB3:

Construction Phase 1

All the stuff in Phase 1 gets soldered using "Organic" Solder.  At every break in the action, we wash the board off to get rid of the flux.

Jumpers

they go here

We soldered one of the jumpers in the wrong place - the horizontal one to the right of "TB1." We corrected it in the next step.

Resistors & Caps

Note the corrected jumper.

Semiconductors, Sockets, Power Stuff

Bottom Jumpers

Construction Phase 2

All the stuff in Phase 2 gets soldered using "No-Clean" Solder and the PCB doesn't get washed off from here on.

Wires

Mounting the PCB

We decided to use a little plaque we found at a craft supply store as a base to mount the PCB on.  We put finishing nails in the base to make easy contact points for our Test Meter.

Done with Construction

Set up / Testing

We Used our Digital Test Meter to test the thing. It has + and - 15V in the right places. The Voltage across the test points is 7.5V and without a test transistor in the socket, there's .100 milliamps (that's 100 micro amps or 100µA) across them - perfect!  Sometimes you win.

Use Notes

We started testing with PNP transistors and switched to NPNs.

Works great!