Bill and Will's Synth
Yusynth Saw Animator Construction

September 2008 -

Somewhere along the line this summer, Will and I were browsing the Bridechamber site and noticed that Scott had some YUsynth Saw Animator pcbs available.  So we went to Yves' site to read up on it:

"The Saw Animator module is a very interesting module when you wish to get that FAT sound, usually obtained with two or more sawtooth VCOs, but you are short of VCOs. You can get this typical sound with only one sawtooth VCO, thanks to Bernie Hutchins (JAES, 1981). The Digisound 80 has this wonderful module and Scott Bernardi designed a version of its own. The present module is a somehow simplified but yet efficient version. To get the best of this module, it must be used in conjunction with a mixer. I chose not to integrate a mixer within the module in order to benefit from the dry outputs which are very useful when used with a LFO instead of a VCO. When used with a sawtooth LFO and inputing fixed CVs in the MOD inputs, one can achieve some interesting phase shifted modulators such as quadrature modulation. Well the possibilities are numerous and it's up to your imagination..."

Now as it turns out, a Synth Bass sound is one of the elements we want to be a signature of the cuts on the re-recording of the "One Mad Track" album we have planned for this winter - and we're hustling to get modules built for that record.  We consulted our more knowing pals on line asking what modules might be useful in developing this sound and the Saw Animator came up as one of those modules.

Table of Contents

This page has become really long, so here's a table of contents that we hope will make it easier to traverse:

Background - presents an explanation and Paul Schrieber's initial description of the Module with a couple photos from Larry Hendrey

Modifications - presents details of Larry Hendry's Fine Tune Modification and Paul Haneburg's Tracking Adustment

Construction Phase 1 - Resistors, Capacitors, IC Sockets, Power Plugs, MTA headers

Construction Phase 2 - Trimmers, Panel connections

Set up / Testing

Background - Yves' Design

Here's Yves' Schematic (click here to download a larger version):

Here's the layout of his PCB (this is Yves' illustration - thanks, Yves):

And here's how it gets wired up (again, this is Yves' illustration):

There's more info on his site. But this is going to be a pretty straight-forward thing to do. We're just building it as Yves designed it.

Parts

Will and I have developed a parts-list / bill-of-materials in the form of an XL spreadsheet (as usual).  After some scrounging, we found everything OK. 

Please don't take it as gospel.  Even so, just now we've used it to make our Mouser and Digikey purchases and we are relatively confident in our specifications.

Click here to download our XL spreadsheet Parts List

Panel

We got ours from Bridechamber:

The Bridechamber panel comes with a 1/4" LED hole - so we need to drill it out to the 5/16" size for the LED that came in our 320 kit:

we're going to use a step drill and we marked the 5/16" step


we taped the panel to protect it while we're drilling and then we poked the holes so we knew where they are <g>


by lowering the drill into the hole, we determine where the panel should be clamped


drilling


drilling


hole 2


drilled


drilled out just fine

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.

PCB Front (click on image for larger one)

PCB Back (click on image for larger one)

Resistors

There is a resistor mis-marked on the PCB as 10K.  We discovered this because, as we were trying to figure out where the caps went, we noticed that Yves' parts list doesn't have any 10K resistors listed - so we asked him.  He confirmed that the PCB is wrongly marked.  But we didn't know that as we started work on the PCB...

Here are the resistors soldered in.  We're using all 1% resistors because we have a lot of these around.  We've omitted the 10 ohm resistors - R1 & R2 - and will use ferrite beads instead per MOTM standard.

As usual, whereas we are vigilant about orienting all the resistors, caps, etc. consistently so their values can be read easily (in case we need to trouble-shoot them later), we oriented the resistors with the "tolerance" stripe on the left (relative to the text on the pcb).  We got started doing it this way when we started building our synth and now we do it so all our modules are consistent with each other.  You might want to do it the opposite way - with the "tolerance" stripe on the right.

Capacitors

Capacitors are in!.

Resistors corrected

We pulled out the 10K resistors - so far so good.

We melted the solder and pulled the 10K resistor leads back through the holes.  Then we re-melted the solder on the pads and slid the new, 100K resistors down through the melted solder.  Problem is, as we were pushing the new solder leads through, one of the pads pulled up with the resistor lead.  We think this is 'cause we let the solder get just a tiny bit too cool as we pushed.

Problem is it's one of the bottom pads.  Problem is that's the side where the trace is.  <gack!>  We ended up putting some extra solder where the pad used to be, but we weren't sure it made the connection properly.  We had to test it.

Stands to reason that if the connection is good, there should be no resistance between these points.

Like this.

All's good (cudos to Granddad's venerable old Bell ohm meter).

ICs - Misc Stuff

soldered in - for a high rez pic, click here

we used a five pin .1in MTA header for the power 'cause that's what would fit into the PCB.  This means we'll need to make a special power cable for the module - one with a four pin .156 connector on one end and with a five pin .1in connector on the other end - and we'll have to jury-rig the 18 gauge wire into the five-pin.

Now for the jumpers -

Here's where they go - one on each side.

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.

Trimmers

PCB / Panel connections

Let's take a look at how the PCB will mount behind the panel...

We're figuring out how long the wires should be

We made the Rate Pot and LED wires 6-1/2" long,
all others 8-1/2" long
If we do it again, we'll make all the wires an inch longer so that's what we'd recommend you do.

Mounting Bracket

We got a 2-pot mounting bracket from Bridechamber. The mounting bracket needs modified - the pot holes need drilled out to 3/8" and holes need drilled for mounting the PCB.

Potentiometer Tweek

The pots have a little pin sticking up meant to keep it from turning in the panel... but we don't want this so we're bending it down - out of the way.

Mounting the PCB

Because we want to mount the pcb behind the panel like we do for all our other modules - on the right - and also we want the pcb to have the power header at the back with the -15 pin on top, we're mounting it upside-down.

PCB mounted

Mounting and Wiring the Rate Pots

we're putting a flat washer and a lock washer on each pot shaft before we put them through the mounting bracket and panel


We put the pots in loosely with the lugs sticking up to make them easy to solder


The pcb's upside down - so the pot wires criss-cross to get to the correct pot


all done

LEDs

we put heat shrink on the led wire then started soldering first the anode of LED #2




heat shrink shrunk and done

The jacks

we started with the CV2 signal wire to the MOD IN 2 jack "tip" lug


then the SAW2 wire to the MOD IN 2 jack "switch" lug


then the ground wire - along with a 3in piece of hook up to jump ground to the next jack - gets soldered to the MOD IN 2 "shank" lug


now for the LFO2 signal wire to the SAW IN 2 jack "tip" lug


then the CV1 signal wire goes to the MOD IN 1 jack "tip" lug
so just like with then the MOD IN 2 jack, the SAW1 goes to the MOD IN 1 jack "switch" lug and the ground wire goes to its shank lug along with a 3in length of wire.


we soldered a four inch length of wire (blue) to the SAW IN 2 jack "switch" jug


then we soldered the LFO1 signal wire along with that 4" blue wire FROM the SAW IN 2 jack switch to the SAW IN 1 jack tip lug,
and we took the little 3" jumpers from both MOD IN jacks and soldered them, along with another little 3" wire to the "shank" lugs of the SAW IN jacks


the OUT2 signal wire goes to the OUT 2 jack - "tip" lug the wire barely reaches on ours, but you will have made this wire longer


this picture's out of focus, but you can see how the ground wire from next to OUT2 on the pcb goes to the OUT 2 jack along with the ground jumper from the SAW IN 2 jack


and then the OUT1 signal wire goes to the OUT 1 jack "tip" lug


and the ground wire from near OUT1 and the ground jumper from SAW IN 1 go to the OUT 1 jack.  In this picture you can really easily see the ground connections to the three jacks - MOD IN 1, SAW IN 1, and OUT 1.

Construction Done

Set up / Testing

Use Notes

Panel

All we did was imitate Yves' design, but re-interpret it in MOTM format:

So we made a FPD design - just to try it out.  Click here.

As an experiment, we ordered the panel from Front Panel Express. Here's what it looked like when it came. The paint is flat, the text wasn't exactly right but close. We adjusted the FPD design. As an experiment, this was great. But we'll probably use FPE only for panels no one wants to build for us.