Friday, 24 May 2019

Metro-Modular 2102 - Dual Stereo Locator - build notes

These are some un-official build notes for the Metro Modular 2102 module.
It's in Buchla format.
For more info on this module click here:

The official build notes will be released later.

The virgin PCB and panel

In addition to the main circuit, Justin has added an extra scaler & a JFET tester/matcher circuit at the top of the PCB.
i STARTED building the input  scalers section on the top left of the PCB then realised I didn't need it as I was going to install it into my Buchla 100 system.
The whole input scaler section is only needed if you use the module with 10V function generators.
Vintage black knob 100 Buchla is 15V.

I usually start with resistors then add caps.
The resistors I'm using are metal 1%.

 Get some 15mm hex standoffs ... female/female.
Yes I agree with Jim. West is Best !

You can also buy a C&K equivalent from Mouser.
You will need to trim the shaft. I'll probably use shears rather than a hacksaw so I don't get grit in the mechanism. yOU ALSO NEED TO RETURN THE SWITCH TO POSITION 1 AND SET THE STOP PIN TO 2.

I'll probably end up soldering the JFETS directly to the PCB, though I have added a socket for the tester.
The JFET matcher is dead easy.
Simply stick the JFET in. and put multimeter probes on the two test points.
Read the voltage.
The voltage should be between 0.7V and 1.2V
The voltage corresponds to the saturation voltage of the JFET
The JFET can be put in back to front (in the test socket only)
The 1k resistor used in this tester must be 1%.

Choosing the JFETs
 If you are unfamiliar with JFETS check this link out.

J201s might work, though you will probably need to go through a few to find enough within the correct range.
The bottom two could possibly be PN3819 or J202 ??
2N4339's from mouser are pricey. There is a long waiting period for the PN4339.
How you mount them will depend on the format.
If they are in a T0-92 package  they need to be mounted "backwards" .... with centre leg pushed forward..... ie the flat edge of the JFET body faces away from the front..

I ended up buying some tin can 2n4339s on ebay.
Not sure if these are fake ... :-)

 These are in a TO-18 package

The input scaler section

This is only needed if you use the module with 10V function generators.
If you are using it with 15V peak black-knob 200 or 100 gear you can ignore it.

If your power supply has +24V just connect the 24V to the rightmost pin of the regulator socket.


Metro-Modular  are from Sydney Australia. 
The new modules being released for SuperBooth 19 are:

 1.  The Boethian Wheel - Model 660
 2.  Dual Stereo Locator - Model 2102
 3.  Roomic Cube - Model 680
 4.  Dual Balanced Modulator - Model 2315
 5.  Todliche Finger - Model 601

+ All about transistors & JFETS
+ Transistor Matching
+ JFETS - matching for synthesizers  

Some Links
+ Metromodular Facebook
+ Metromodular Youtube
+ Metromodular website  

My Metromodular Index Page

222e notes

Some notes regarding the 222e Kinesthetic Input Port.
Just getting this out of storage and reacquainting myself with this old friend.
It's a beautiful module and interface.

You will need either a 206e or 225e if you wish to memorise and recall any of your settings.
(Blue knob)

The "Thunder keyboard' is amazing. 
The 27 keys sense pressure and velocity.
You can generate pulses and control voltages with pressure and impact.
14 of the keys respond to location in one or two dimensions.

The 222e responds to 2 types of user movements .... touching the keyboard & the position of the user's hands in space. Don was all about seamlessly joining the musician to his creation.

The LCD display is how you program the module.
The states are changed with the page key.
Use the cursor to select the desired pulse.

This first page deals with pulses.
Blank = normal .... a pulse is outputted upon touching a key
T = toggled response with alternate touches reversing the state.

Next we have the Radio State
There are 4 pages: 6,7,8,9.
It's named after old car radios.
You select the page with the DATA entry knob.
Ky= key.
Use the cursor button to get to the desired field.
You choose the keys just by touching the thunder keyboard.(or disable with a second touch).
To escape from this mode, cursor to the “ky” field and with the data entry knob, decapitalize it.

After the key, you select the type of voltage:
Loc =L = Location
Prs = Pressure
Imp = Impact

Below are the CV outputs .... set at zero volts in this instance.
CV ranges between 0 to 9.99V (decimal point is ignored)
The second voltage appears on the blue jacks. (these can also be used to present location)

The bottom row of jacks provides access to Location, Pressure, or Impact from individual keys. 
It's called CV OUTS 
Select this group using the Page Button.

Use the Cursor button to move through each CV OUT  (the DATA field)... 10,11,12,13,14.
Use the data knob to select the data type.
Here we can see the data types for each field:

10 : Iv (I = Impact)
11 : Pw (P=Pressure)
12 :Px
13 :Py
14 : Pa
 The lower case letters are the keyboard keys
The next page allows the display contrast to be adjusted for optimal viewing.
Pick a number between 0 and 7.

This is achieved by "stealing" radio outputs

Use the data entry knob to select from two to four voices. The display will indicate which of the radio outputs have been “stolen” for application to polyphony.

The final page allows us to determine the effect of the two small keys located on the upper left and the upper right corners of the keyboard.

The status of these keys determines whether the rings are engaged or not.
In this case, both these keys are lit.

The keys can be switched from the toggle to the sustain mode, and thus determine the effect of the rings. If the R (of rev) is capitalized, then the effect of the keys is reversed, with the left key controlling the right ring, and the right controlling the left.


Spatial sensor

The red strap identifies the left ring; the green identifies the right (nautical conventions).
The rings are conveniently attached to the first knuckles of the index fingers, with the little windows facing away from the body. The buttons at the center are the switches for the rings.

The shape of the performance space is sort of a square cone radiating from the square widow on the front of the 222 control module. The range is from about 4” to around 5’, with a lateral and vertical space proportional to the distance.

An orange LED is illuminated whenever a ring is in the field.