Moog Music Forum

noddyspuncture wrote:Can you build me one please Terry...!?

Have to build the first one!
I think that L bracket drilled and tapped will be main part of building a Moog type X-Y controller. Once I have that bit squared away it should be easy to make duplicates. The first one is going to be a clone, but adding an S-trigger button. After that, any combination is possible, dual joysticks and even a depth pot to replace the stock configuration rockers. It looks like the main part is just a bracket that mounts like all the Moog wheels do, with a different square cutout. So these could be mounted anywhere there is room.
I'll post all the dimensions and troubles I have making that X-Y movement. This should be easy for anyone to do once the kinks are worked out. Hope the 3/8" X 1" L stock I ordered will do. Already changed the stick dimensions from 7/16" to the correct 3/8". A learning process!

Pilot hole for the alum rod a must I would think.

Looking at the 10k pot how did they indicate audio taper on these particular make?
I cannot see A or B ? But audio must be the choice due to limited wiper travel ?

Looks a great job so far....very inspiring !

rarecomponent wrote:Looking at the 10k pot how did they indicate audio taper on these particular make?

Part of the secret code on the back of those AB type J pots. Not all had this code and some OEM pots had no such code on them.
Not sure where I found this, but someone was nice enough to share.
Here is a breakdown of the code:

Explanation of AB Type J part numbers, to aid in identification of surplus pots:
Example from above post: JA1N200P504AA

JA = Single section type J
(JS = single with switch, JD = dual, JB = dual with switch, JE = triple)

1 = Standard locating lug location
Facing the shaft, with solder lugs at bottom:
1 = Lug at 9 o'clock
2 = Lugs at 9 and 3 o'clock
3 = Lug at 3 o'clock
4 = No lugs

N = Plain bushing, 0.375" long
(Other options are for different bushing lengths, locking bushings, watertight bushings, etc.)

200 = Shaft length in inches (2) and 64ths (00)
056 would be 56/64" (7/8")

P = Plain round shaft ending
(S = slotted, F = flatted)

504 = Resistance 500,000 ohms (500k)
(The 4 indicates the number of zeros following the first two numbers. 254 is 250k; 105 is 1 meg.)

AA = The first A indicates taper and tolerance:
A = Clockwise modified logarithmic, +/-10%
R = Clockwise modified logarithmic, +/-20%
B = CounterCW modified logarithmic, +/-10%
T = CounterCW modified logarithmic, +/-20%
D = Clockwise exact logarithmic, +/-10%
K = Clockwise exact logarithmic, +/-20%
U, M, S, Y, C, and F are linear tapers

The last A just indicates what mounting hardware comes with the pot.
A = one mounting nut and one lockwasher

Update: Received the L stock to make that part of the movement. Can see now that there is only about 30-40 degrees of travel for each pot. Might be why the audio taper was needed.
When I get the round stock for the handle I will test the voltage output.

Thanks for detailed and elusive info on the pots...thats a very Germanic way of doing things for sure ! Amazing where you get this info from !
The developing XY clone is looking pretty good ....its looking very
well engineered .

The 3/8" round aluminum bar stock showed up today. Still waiting on those type J 10K audio taper pots though. After cutting/drilling/tapping/filing the stick, I can now try the action. Very smooth and a precise feel. This is going to turn out nice. (I hope!) Still have to get those 10K pots and dial in the range to be sure. I can see where having those sloted ends on the pot shafts will be handy for loosening the setscrew and finding the optimum range.
Pic of the "action".

And a side view showing the stick length. Can see where the slotted ends will help to fine tune this.

Another view of the simple but brilliant Moog X-Y action.

Test fiting in a panel to try the action out. Smooth!

Have to get busy making the openings for the rockers in the front panel, while waiting on those pots. Once I have the correct pots I can experiment with the electronics for this.

This is such a great project ....

Those PEC 10K audio taper pots arrived today. They aren't quite as well constructed as the AB type J pots, but are a suitable replacement. The pot shafts are a little different with the PEC type having a C clip and a little less turning resistance. But these seem like high quality parts. They have some of the more difficult to find Moog values like 50K audio reverse taper and 1 MEG audio pots. Both used on Mini and Modular in various circuits, and are readily available from PEC.
AB type J on left and PEC on right.

Rear view of both.


So I was able to test these out and a few other value pots. The 10K audio had the widest range when tested. With a variable bench supply, I tried the different supply voltages, +12/-6 from the modular, +/-10 from the Minimoog and +/-15 volts.
The full and 10% switch either grounds through a 1K for the 10%, or a combined 9.1K and 1K for the full setting. (About 10K to ground.)
Calibration was done by turning the pot voltage untill it reads zero volts, then positioning the joystick centered and tightening the setscrew. This gives a +/- voltage from the joystick. Tried calibrating for zero volts with only a positive output, and the end of the travel had little effect. So I would assume this was intended for +/- voltage with zero on both axis at dead center.
At +12/-6 supply voltage:
Full setting +2.5V to -1.5V = 3.5 volt swing.
10% setting +1V to -.55 = 1.5 volt swing. (Both less than I expected.)
At +/-10 supply voltage:
Full setting +2.5V to -2.5V = 5 volt swing.
10% setting +1V to -1V = 2 volt swing. (1K and 9.1K could be factory selected for Minimoog?)
And +/-15 supply voltage:
Full setting +4V to -4V = 8 volt swing.
10% setting +1.5 to -1.5V = 3 volt swing.
Seems to work well enough when centered/calibrated. Very precise, and even at full range I was able to tune oscillators to any note in the range. A 10K pot could be substituted for the 9.1K resistor and rocker, for a variable range centered on zero. Would still want the 1K to ground though.

Still working on the enclosure. Made the bottom from the same type particle board found on the back of the R.A.Moog 950 keyboard.
Cut to a nice square.

Had to make a small U shaped cutout for the accesory cable. Using the standard Moog type Cinch 8 pin. Back cutout with the black painted bottom piece.

Applying a tung oil/poly type finish to the box. Will need a few more coats.


Still have to make the cutouts for the rockers on the panel, and waiting on a few more hardware parts. Guess I'll end up painting the front panel?

Weekly progress update.
The hardware arrived for fastening the various parts together. There were a few differet types of black oxide finish screws I needed. Moog modular front panels use the same 4-40 oval head machine screws, and I needed matching #4 oval head wood screws. Also needed #6 flat head wood screws for fastening the bottom piece.
Here are the three different type used.

Also had to go back and remake the L bracket. The geometry was a little off, and had to relocate the 1/4" fixed pot a little offset from center.
The L stock is drilled and tapped from a larger piece to work easier with, then cutoff to size.


The front panel needed the rocker cutouts and a location for the trigger button. Trigger button like a game controller located for easy thumb access. Screw holes are counter sunk for the oval head screws to mount flush.


Experimenting with painting the front panel. Will label then clear coat. The original Moog panels are black anodize with etched lettering.


Test fitting together. Trigger button looks a little strange, but a very usefull addition. Almost looks like a 959?


I am still waiting on some parts. Will have to make voltage output measurements again as I did not get the full output CV's right. Looking again at the circuit, 10% setting was correct with the combo of 1K and 9.1K to ground. But when switched to full there is only the 1K to ground, but I missed the 9.1K then routes through the wiper CV. My above measurements were done with the wiper CV unattenuated. So the full CV will be a little different voltage swing.
Slowly getting this all together.

AWSOME!!!!!!!!! Verry verry nice stuff! Congrats on that!

Time to wrap up this project! The last parts I was waiting on arrived, so I can get this all together now.
Was able to source the original type pots used in the 959 since those PEC pots had a slightly different feel to them.
Found a set of originals for not much more than those PEC type cost.


For the accessory cable I had an original Moog type. Not sure the Belden part number on the 8 conductor cable, but both the black and red wires are thicker guage than the 6 others.
Moog wiring is: red= +voltage, black= -voltage, green= ground, yellow= S-trigger, white= S-trigger ground, blue= V-trigger, brown= CV1 out, orange= CV2 out.


Still had to label the front panel. Using dry transfers, I was able to get close to the original design. Had to use a bit of imagination as I did not have a % or the arrows. Just used small zeros and a larger I to make the %. And a line wth an A for the arrow head.
Applied a clear coat after labeling.


Only have one photo of the bottom of the 959 from a VEMIA auction.
Looks to use the same type rubber strips as the 956 linear controller has.


So I used a similar non-slip type rubber strip for the bottom panel.


Time to test fit everything together. Looks OK but the glossy finish on the front panel does not look right. (Looks like a fake Moog panel.) Has a bit of dust and orange peel too.


I figured I would have to re-do the panel, but tried to fix it by wet sanding with 1000 grit. Ended up being a happy accident. I noticed after sanding a bit, it got that same dull, kind of chalky finish the Moog anodized panels have. I almost can't tell this is painted and not anodized. I will use this method again with all my Moog clones.
Is it painted or anodized?


Time to wire this up. Not much to it really.
Starting to wire it.


After wiring, fitting everything in the box.
All it is missing is the little circle "104" stamp.
Has the usual Moog strain relief knot in the cable.


After calibrating the pots to zero volts at center, the last step, drilling and fastening the bottom with the #6 flat head screws.


View of the front.

View of the rear.


Now the fun part, taking it out for a spin. I have never used an original 959, but I am quite confident this is a very close copy. Bob Moog designs are usually well thought out and very musical. This 959 is no exception. Plugging the 959 into a Minimoog with red into the VCO and black into the VCF yielded some very expressive control. With the VCO axis set to 10% there is only a few semitones of pitchbend in either direction with a zero center. Had the VCF axis set to full. I was immediately able to get great pitchbends with filter "wah" while playing the keyboard. Freekin' awesome way to play a Mini! The trigger button is an extra bonus and nice playable addition. With the VCO axis at full, about a 4+ octave range, I was able to get all kinds of sound effects not possible with just the Mini keyboard. This 959 X-Y action is very precise with no backlash or lag as it is directly connected to the pots. Similar to the Voyager touchpad, but more accurate and a different way of playing it. Add in a modular type patching scheme and the possibilities are almost endless with this type controller.
As much fun as this was to build, using it is twice as much fun.
I'll have to put together a YouTube video to demonstrate some of the patching possibilities. Had a patch with the 904 Low Pass Filter on one axis and 904B High Pass Filter on the other axis while a sequence was playing. And even had the trigger button firing a 911 envelope generator.

Another big thanks to Timothy for sharing photos of the inter workings of the 959. Once I could see how Bob and Company did it, making a copy was easy.

AWESOME..... now can you make me one....

Cheerz,
Tom

Congrats on a first class job C Z. !

The whole project and the way you presented it is as good as any project manual plus excellent photos.

This looks good, really good and I expect will be a joy to use.
I admire the way you stuck to authentic construction I know how hard that is. Its almost indistingusable from the original.

I've got some great tips from this project too and will try the finish you got on the panel etc.

By the way do you have any schematics regarding voltages going to and from the two pots? I will be using 12v / -6v . I think these go either side of the log pot and wiper is out put via one of two resistors
grounded ?

Tom, you are first on the list if I ever make these to sell. You never know?

As far as the schematic, this 959 was reverse engineered from a few photos with little else to go on. I drew one up, but there is a possiblility that Moog would use a different resistor combo for the modular +12/-6 supply. I tested this on all the power supplies and the symmetrical ones +10/-10 and +15/-15 were calibrated, and the zero spot was the same. With the Moog modular supply +12/-6 the pots had to be re-calibrated for the zero center. Timothy, the original owner purchased this for a Minimoog back in the early 70's and it had the 6-prong Cinch/Jones male end for powering.
Have to be carefull with this design, as it is intended for a 40 degree pot movement to get the optimum range. This means turning the pots fully CW or CCW will send out higher voltages than the circuit is designed to handle or send out. It really needs to be calibrated before using to make sure it is not outputting too much voltage. One could short out your power supply if it was outputting full rail voltage and the tip of the black/red plug touched ground. It seems fine for the smaller voltage swing it was designed to put out.

Here is the schematic of the one axis since both are the same.



Can see by the way I drew this, the SPDT and 9.1K resistor could possibly be replaced by a 10K linear pot. This would give a variable scale from 10% to full. Might be the way the wedge type was wired up.

I'll have to break out the bench supply and make some measurements of the output with the various supplies. With +10/-10 volt supply, the 10% setting patched to the Mini oscillators is two semitones up or down. Perfect for pitchbending and I can see what they were going for with that limited voltage swing. On the modular with attenuators, amplifiers, inverters, any range/scale is possible. Just had a patch where the one axis was controlling just one of three oscillators for guitar like unison bends. Always wanted a third wheel with a detent on a Mini for that. Thinking of that Pat Moraz solo with Yes on the Relayer album. Having fun with the 959. Wonder why it took so long to get one now? So many uses!

Thanks for posting this schematic and the voltage warning too !
I will do a test run just with two 10 k pots and do some twizzles ...then hopefully do the custom CZ XY controller .
How's it sounding?

rarecomponent wrote:How's it sounding?

Guess I did promise a demo.
Here is a small demo uploaded to Youtube. This is powered from the Minimoog +10/-10 and controlling the IP modular. Sort of gives you an idea of how it works and the possibilities?
Youtube demo of the 959 X-Y Controller Clone

I first read about the 959 in the original Minimoog Operations Manual. Listed as an accessory for the Minimoog.
From the Minimoog manual with the page dated July 1971.