Synth tech news

Update

I received 2ea MOTM-730 VC Divider Rev B (added 3 pullups) CPU boards. The pre-production sheet metal panels are due to arrive Tuesday PM (5pcs, cost the same as 2pcs so.....). Hopefully I will have some pictures Wed PM of the 'real' module and I'll get out my new USB-based logic analyzer and grab some screenshots. I have already soldered most of the parts on to the 2 boards. I can do the 1206 parts with ease, the 0603 parts are really a pain :(

Also shipped (by ground) are 300pcs of various front panels. This should keep me in panels for the next 6 months or so.

I am off the next 7 days from my 'real job' so I will be able to do a LOT of catching up. Here is what I plan to do:

a) ship *every* MOTM 2.0 outstanding order
b) finish making the '420, '190 and '800 kits
c) complete 12 assembled modules (I just finished making 8 MOTM-910s today)
d) build 20 Frac modules
e) get the CGX pc boards to prototype fab (actually, there are 4 different boards in the set)

I will be available to chat at 817 281 7776 if you want to call and check up on your order (no I don't mind).

I will be MOTM vacation July 7-11, no shipments, no work except I will check email.

Paul S.

Great stuff, I should be back home on the 4th, hopefully have some kits waiting for me to be assembled :-)

Jeff Laity's MOTM construction

Jeff recently wrote me to share news about his synth construction. He has build a nice walnut 24U cabinet, and has now started adding modules, so it's starting to look like a modular. In the picture can be seen: Left to right: 300, 300, Bridechamber mult, CGS/Bridechamber sequencer in progress, 420, 190, another CGS sequencer that's further along.
Parts for two 800s and a 490 are on the way....
Pictures of his construction can be found here.

Nice work Jeff, love the wood color too, and it's in great company too, judging by the Moog Minimoog Voyager and an Alesis A6 Andromeda.

T J

Rendering of the MOTM-730 VC pulse divider

Synth tech recently published the design of the MOTM -730 .
Paul writes:
Here is an illustration of what the front panel of the MOTM-730 VC Pulse Divider will look like.

The big version can be found by clicking here.

Thanks to Ken Tkacs for helping with the Corel Draw artwork. I hope Dave Bradley can get well (been sick several days), he is working on a detailed rendering that will look more realistic. Ken's is for the actual silkscreen used to make the front panels from my AutoCAD drawing (which in turn was greatly assisted by Tim Servo).

There is a 'bug' in the drawing, the DIVIDE switch is in the wrong position for what the display is, that's my fault (didn't catch that until just now).

I should have a production sample for Robert Rich to torture-test on July 3rd.

Some additional info:
The STEPPED output is an 8-level rising sawtooth (starting at 0V and going positive). The 4/O/5 switch is the step size. It is not calibrated, but "close enough for rock". The 2 prototypes were within 4mv of 'correct'. You can always use a FM attenuator to 'dial in' if you want.

Production/delivery in late August. Just doing all the CAD work now and handed off, still concentrating on getting the backlog shipped. I made quite a dent this week, shipped 17 orders and finished the MOTM-420 kits. Next up: MOTM-190s.

Paul S.


Looks great Paul!

T J

So what about the Cloud Generator+ Expander?

Some readers asked me what is to happen to the cloudgenerator, when will it be coming out.
It just so happens that on the MOTM group at Yahoo, Paul just provided the answer, here it is below:

The reason I went ahead and 'brought out' the MOTM-730 ahead of the CG/CGX has to do with the CAD system upgrade I did about 2 years ago.

I use OrCAD schematic capture, I have been since *1986* when I was a beta tester :) And, every MOTM module up to and including the MOTM-650 was designed in OrCAD......for DOS!

However, I switched over (very late, at the "last and final offer we mean it REALLY" letter) to the Windows version. I did not want to 'plunge it' with the complicated CG/CGX so I decided to use the '730 as the guinea pig. The mistakes I made had nothing to do with switching over the CAD, it was me being an idiot.

I now can navigate my way around the new Windows version (it is very different than the DOS version) and now am ready to tackle the CGX first, then the CG electrical CAD. Both schematics are 90% done as of today, tomorrow is going to be a "CAD day" emphasis to correct the '730, send the 3 other boards in that set out for production, and finish up the CGX schematic so Eric and I can review it (Eric is the lead designer, I just try not to screw it up). Robert Rich is the 'System Architect's and I am the 'Head Peon'.

We will "sign off" next week on the schematics, I will then start the pc board CAD and the mechanical CAD (with assistance from Tim 'Servo not MST3K' Parkhurst') around Wednesday of next week. I want to ship all existing MOTM 2.0 orders before then.

The mechanical CAD is about 80% done for the CGX as well, there are 4 boards and the LCD panel, but not as complicated as the '730 is. There is a breadboard up and running so we have code that can do everything except the full USB librarian function (if anyone wants a FREE CG/CGX set of modules and will write the librarian for *both* Mac and PC, email me off-list).

My plans right now are to have a few production-ready CGX prototypes in mid-August.
I will then turn attention to the CG itself, which is mechanically done (I have 63 finished panels sitting in the garage for....errr...a long time) but the pc board layout will be very involved (probably a 6 or 8 layer board, hoping for 6).

I would say right now shipping the CG/CGX set will be around Nov 1st. The *current* backlog has 95% of my available bandwidth until it is shipped out. I and planning 8 consecutive days in late June/early July for purging the backlog (my day job is in 'Summer Shutdown'). The sooner I can ship the backlog, the sooner the CG/CGX ship out.
Eric & I are confident of the overall design, it is not more of a CAD/manufacturing issue and getting the final code ready to ship.

Paul S.

So there you have it, hot of the press :-)

T J

Synth tech tests VC 730 proto type

Paul posted this extensive 'report' of the test and it's functionality.

I have finished my initial testing of the production-ready (almost, see below) pc board set for the MOTM-730 VC Pulse Divider.

The board set consists of:

a) vertical-mounted jack board (uses new Switchcraft RoHS vertical jacks)
This connects to CPU board via 34-pin ribbon cable

b) pot board, uses 2 of the Frac-style pots/knobs, connects to CPU via ribbon cable

c) switch board, has 4 NKK pcb mounted toggles, connects to CPU via header pins

d) CPU card, a 4-layer pcb ~ 3.5 " x 3.5", mixture of SMT and thru-hole.
Contain s 2 PIC processors, 1 drives the 3-digit 0.56" LED display, the other does all of the physical counting/dividing.

e) LED display card, contains the 3-digit display, connects to CPU via header.

The CPU requires the 6-pin MOTM-950-type power connection, as +5V at ~ 65ma is required in addition to the +-15V (at ~ 10ma). I will not offer stuffed/tested CPU cards until after I have sold 100 modules :)

I have spent ~ 20 hours checking this thing out over and over. I need to add 3 10K pullup resistors on pins of the PIC controller, that were on the prototype but someone (me? [cough]) had crossed them out and wrote 'Not needed' but guess what? NEEDED! The part has open-drain pins and needs a physical pullup.

Other than that, it seems to work flawlessly. Input frequency can go up to around 15Khz before 'glitching', although the primary application is firing off multiple EGs when driven by LFOs or low audio range (say 100Hz CLK IN). The outputs are 0 to +5V square waves (or as close as we can get to square, depends on the math) so they can be directly connected to EGs as a GATE input. The outputs are driven by a 74HC244 HCMOS buffer and a 100ohm series resistor.

The '730 has 11 fixed divider outputs and 1 variable divider output. There is toggle switch to select a '1/2 divide', meaning all of the divisors are scaled by 2. Yes, this means *fractional division*, like dividing by 1.5, 2.5, 3.5, etc. When the toggle switch is in the 'HALF' position, *all* divisors are affected.

The fixed divisor ratios are:
2, 3, 4, 5, 6, 7, 8, 9, 11, 12 and 16 in 'FULL'

The variable (in 'FULL') goes from 2 to 32. There is an 'INITIAL DIVIDE' pot, and a CV input scaled for -5V to +5V full range, and a CV MOD attenuator.

There is an input jack called RUN/STOP and when pulled *low* (ie shorted to
ground) the unit resets. Can be used as a sync, but this input is *level sensitive*, not edge.

Lastly, there is a "fun" output called STEPPED CV. This is a moderately accurate (1%) 3-bit DAC connected to a 3-bit up-counter. This will generate a positive-going stepped 'sawtooth' waveform. The step size can be 1 of 3 switch-selected options: 4th, 5ths or Octave.
This output is *untrimmed*, but good enough for messing around. You can always use an input attenuator to tweak in closer. The clock the counter uses is switch selectable between the input clock or the divide-by-N output.

The 4th switch selects the positive or negative-edge to trigger the divider.

I already have production quantities of the display board, and will order
the switch, pot and jack production boards in ~ 1 week. This weekend I will add the 3
missing pullups and run the unit 72 hours straight at full speed to see if there are other issues I missed. I will then order production CPU boards.

I am making 100 modules up, in 2 batches of 50. If these sell out, I will make more.
I can only afford parts for the first 100 right now (I just spent $4200 on more parts yesterday and $1350 today).

I still need to design the front panel, and get a few prototypes made to be sure I did not screw up mounting holes, the LED bezel cutout, etc. It is a *tight* fit, as 3 of the boards stack up and they have to be perfectly aligned for the header pins to mate.

The cost of this module will be $399 and I am looking at a Oct 1st date for
the first 50. These will be *in stock, packed in boxes* the day they are announced.

OK, I'm pooped. Back to kitting and shipping this weekend. The MOTM-410 and MOTM-120 kits are all done. Moving on to MOTM-420 and MOTM-440 this weekend. I also have the pc boards in to make ALL of the MOTM-910 mults.

Paul S.