Colorsound Vocalizer vero

[pinkjimiphoton]

i checked the mp16b's with my meter bro, they're indeed pnp. i tried 2n3906, didn't matter. i think the transistor's not being used for tone, but for switching , i think that's why it's making that bump sound under operation. dunno. give me a little bit.

[digi2t]

Yup, phector2004 is right, it's not in the signal path, so it's switching.

I don't know what's going on with jimi's build to have to jumper between the 2 pot sections, and I'm also wondering that the bias for the ge transistor would be set up for the lower turn-on voltage for a ge, so a silicon tranny might not give the same results. The 3 x 1N4148's set the max turn-on bias at approx 1.8V across emiiter to base. The pot would vary the base voltage from that 1.8V max to around 1/12 of the 4.5 volts available = 0.375V.]I don't know what's going on with jimi's build to have to jumper between the 2 pot sections, and I'm also wondering that the bias for the ge transistor would be set up for the lower turn-on voltage for a ge, so a silicon tranny might not give the same results. The 3 x 1N4148's set the max turn-on bias at approx 1.8V across emiiter to base. The pot would vary the base voltage from that 1.8V max to around 1/12 of the 4.5 volts available = 0.375V.

This makes a lot of sense since a Ge vbe(on) voltage is usually around 0.25vdc, much lower than Si.

[digi2t]

OK... I dropped R.G. a line, and the man was kind enough to send me the following analysis... on a Sunday no less! I tell you all, the day this guy leaves us, he's on the express lane to the big guy upstairs! No waiting in line  . In the meantime, lets put on a pot of coffee, settle back, and enjoy another gem. Guaranteed to send you to bed less stupid tonight;

That circuit works like this:
Transistor emitter pulled up to 4.7V by 3K resistor; base is pulled down towards ground by 12K fixed resistor, but pulled back UP to 4.7 by the pot and 1.2K. The three diodes prevent the base from being pulled down toward ground by more than three diode drops.

The base-emitter drop of the transistor is approximately the same as one of the three diodes, so without the pot and 1.2K resistor, the base sits at three diodes (about 2.1V) below 4.7V, so the transistor action forces the emitter to be about two diodes (1.4V) below 4.7V, which in turn forces the current through the 3K resistor to be 1.4V/3K = about half a milliamp.

It can't get more than that. And the collector current must be very close to equal to that, and this current is what goes into the bias terminal of the 3080. It's a current source feeding the 3080 bias input.

But the 1.2K and pot do exist, and they pull the base back up towards the 4.7V bias source. In the center, the pot is 11K +1.2K or 12.2K, and at either end, it's 1.2K. Pulling up on the base can raise the base because the diodes only limit how far down it goes, not how far up it can be pulled.

At both ends of the pot travel, the 1.2K and the 12K to ground form a voltage divider downwards from the 4.7V bias voltage. The voltage is 4.7* (1.2/(1.2+12)) = 0.47V down from 4.7V, or 4.27V. Notice that this is less than one diode drop or Vbe drop, so the base is pulled UP so much that there is either none or almost no current for the emitter, and the bias current to the 3080 goes to zero, shutting it off.

At the middle of the pot travel, the pot is 1.2K + 11K, or 12.2K, and the voltage divider action on the base tries to let the base go to 4.7V - 4.7V* (12.2K/(12.2K+12K)) = 2.33V. However, the three diodes keep it from getting lower than 4.7V-2.1V = 2.6V. So with the pot in the middle, the current rises to half a milliamp, about.

The pot action is to start the current at nearly zero with the pot at one end, increasing to half a milliampere at the middle of travel, then decreasing down to zero again. This is approximately the right behavior for a vocal formant if it's the lower F1 formant.  So if what the 3080 does is to change the frequency of one of the filters reasonably linearly, that's going to work.

The characteristics of the transistor seem to be about right for a silicon PNP to me. I'd stick in a 2N3906 and try it.

You can check to see if it's working by reading the voltage across that 3K resistor with a meter. It should be a minimum of nearly zero from end to end, and go up to about 2-2.1V with the pot in the middle. On the collector of the transistor, the DC voltage to ground should go from about 0.5V minimum to about 3.5V max if all this is working right.

You can check the operation of the filters this way:
Remove the 4.7K from pin 12 of the 4136 to the output. This lets you test the other filter.
Put through a signal and see if you hear a resonant sweep from the output. If not, that filter's not working. If it is, put the 4.7K back in and remove the 2.7K from pin 10. This now tests the filter controlled by the 3080. It should sweep up, then down as the pot is rotated. If not, it is possible that the 3080 is hosed (they're fairly fragile) or the filter is not working.

To test if it's the 3080, disconnect the wire between the two 4n7 caps and pin 6 of the 3080. Now use a pot between the 4n7s and ground to see if the filter sweeps. If it does, the 3080 was the problem. If not, the filter has a problem even if the 3080 is working. The 3080 acts like an electronically variable resistor in this setup.

As a general check on the opamps, all pins (+, -, and output) on the quad opamp except the power pins should be sitting at the bias voltage of 4.7V.

Check the pinouts and power to the opamp chip. I always hated the 4136. I hope you've replaced it with a different and more modern device, adjusting the pinout accordingly.

And there you have it. TL074 can be a reasonable substitute for the 4136, like I mentioned earlier, I can redraw the layout to accomodate, and will. The NTE996 should be alright as a stand in for the 3080.

A great big THANKS to R.G.

[pinkjimiphoton]

ok, i messed with it some more, you won't like this, but it works...

i got it working. it sounds KILLER. but ...here's the weird thing. i think the colour codes were changed, or this weird ass pot i got is wired funky by drummers on lsd.

here ya go...using your method of pot 1 being closest to you, and pot 2 being closest to the spindle, and lugs being 1-2-3 left to right from the back of the pot.




this is the only way this thing seems to work...read 'em and weep.

pot 1
lug 1 grey wire on your vero layout
lug 2 white wire
lug3 no connection

pot 2
lug 1 purple wire
lug 2 blue wire (brown, on mine)
lug 3 TIED DIRECTLY TO GROUND.

that goes against the picture, i know, but with this pot (the one i found on evil bay) this is definitely the way to hook it up. every other way was weird, making knocking sounds as the treadle was moved, or the pedal working backwards....ie, toe down= more bass. now the wah is definitely happening, the fuzz indeed works as a contour control,and it has plenty of baallz. now if you re-connect the 330r resistor it's at unity gain, as well. but i like it disconnected, cuz it has way more balls. i may make this switchable.

i will try and get a video demo done tomorrow...i think we've cracked this nut finally.

[phector2004]

Hey man,

Glad to hear it works, even though the wiring's a bit different

Pot1 seems fine (same as schematic)
Pot2 is supposed to have 1 and 3 connected, and nothing connected to ground... does it vocalize? I think that filter's supposed to sweep up and back down while the other one keeps sweeping in one direction

And thanks big time for testing this out!

[pinkjimiphoton]

to get something straight dino, YOUR LAYOUT is 100% on the money with the schematics and gut shots. well done bro!!!

i wanna see what happens with your build, and if the custom pots make a difference.

i just tried this thing into a clean amp, little reverb with the cans on...and man. DEFINITELY formants at the bottom of the pedal travel. more than a wah, and similar to the pII other than not having the "animation". the fuzz control mainly seems to be a contour, it changes the feel of the fuzz and seems to add sustain.

absolutely killer pedal. i can't believe i built it!!!

i did make a little mod, too...i put a 500r trimmer in series with the 330r resistor, so i can dial in the output to unity gain or above. 330r is probably unity, but seems a little weak to my ears, probably cuz i'm deaf.


giving it a little more output is good...no resistor, and it sounds boss, but don't try and put anything after it..i tried it with a fuzz, and could completely overdrive the fuzz to the point it sounded like compressed lightning bolts. uglyface-ish. cool, but not necessarily useable. 330r makes it play nice with other pedals, but is a little too "tame". try a 470r instead maybe, up to 1k or so is probably plenty. out of the circuit, it's a great lead boost, but make sure dirt pedals are BEFORE it.

anyways, it works, and kicks some ass.

[digi2t]

to get something straight dino, YOUR LAYOUT is 100% on the money with the schematics and gut shots. well done bro!!!

Hey bro, does that mean that lugs 1 & 3 (purple) are tied together now, or are you still running 3 to ground? I thought about the voltage divider idea, but it goes contrary to R.G.'s analysis. I would really love to know, so I can correct the original layout if required.

A 1K trimmer in place of the 330R is an excellent idea. I guess if you really wanted to get fancy, you could drill a small hole in the bottom for a small screwdriver for adjustment, in case your setup changes.

I took R.G.'s advice, and have drawn up another layout, using different IC's (NTE996 and TL074). Again, I triple checked it, but I'll maintain it as UNVERIFIED until further notice.



I managed to get the board smaller by one hole as well, and I spaced the 330R resistor to accomodate a multi turn trimmer in it's place, center cut for the #2 lug included .

[soggybag]

Might be good to have a version with TL074 and 3080. Not sure but it seems that 3080 might be easier to get than the NTE part.

[digi2t]

3080 and 996 have the same pinout, so 6 of one, or half dozen of the other. According to R.G. a silicon PNP tranny should work in here as well.

[Ronan]

So nice of R G Keen to reply, he must have a heart of gold.

BC212 is a silicon tranny according to the datsheet I dragged up off the net. I might try to breadboard just the tranny section to see what current comes out to feed the 3080, with a silicon PNP. Won't be tonight though. Looks like the 3080 needs half a milliamp for max gain (transconductance) with a 2mA absolute max before it gets broken. So the sweep of the pot should cause a zero to 0.5mA current across that 3K resistor, corresponding to a zero to 1.5V voltage drop across said 3K resistor. Max voltage should be with the pot in the middle, and zero at each extreme of travel.

[pinkjimiphoton]

to get something straight dino, YOUR LAYOUT is 100% on the money with the schematics and gut shots. well done bro!!!

Hey bro, does that mean that lugs 1 & 3 (purple) are tied together now, or are you still running 3 to ground? I thought about the voltage divider idea, but it goes contrary to R.G.'s analysis. I would really love to know, so I can correct the original layout if required.

A 1K trimmer in place of the 330R is an excellent idea. I guess if you really wanted to get fancy, you could drill a small hole in the bottom for a small screwdriver for adjustment, in case your setup changes.

I took R.G.'s advice, and have drawn up another layout, using different IC's (NTE996 and TL074). Again, I triple checked it, but I'll maintain it as UNVERIFIED until further notice.



I managed to get the board smaller by one hole as well, and I spaced the 330R resistor to accomodate a multi turn trimmer in it's place, center cut for the #2 lug included .

this is how it's wired in mine....

pot 1
lug 1 grey wire on your vero layout
lug 2 white wire
lug3 no connection

pot 2
lug 1 purple wire
lug 2 blue wire (brown, on mine)
lug 3 TIED DIRECTLY TO GROUND.

however what roman says could be true as well tho...it is possible to have it wired where the "peak" is in the middle. imho, it doesn't seem to work as well that way, tho it does work, which is probably the stock intention...put the "wah" treble part in the middle and rock it on and off, contrary to a normal wah wah. i wired mine last nite as a normal wah, which probably accounts for the wiring discrepancy.

but...in the gut shot posted...

and i'm sure of this, after looking at it a bunch...pins 1 and 3 are jumpered (purple wire), and are connected to ground, with the signal going in the middle (blue wire),,,then it will indeed rock in and out of the formant with bass/mudd at each end and the treble/ahh sound in the middle. to me tho, it's just plain not really usable like that, very dark and muddy sounding and doesn't cut thru without some help from a fuzz before it (which gives an insane power wah sound) or after it (where it either overpowers the fuzz and doesn't really seem to be too musical) if the 330 is lifted where it still sounds kinda weak to my ears.

right now, the most annoying thing is the damn treadle is squalking and incredibly annoying. the other day i cured it with a shot of silicon, but no dice last nite. ya gotta have the amp pretty loud to drown it out, which is annoying.

anyone know how to de-squeek a wah?

[digi2t]

A 1M resistor from the pivot pin, directly to ground. Should take care of it  .

Seriously, you'll have to knock out the pin, clean and lube everything, put it back together.

however what roman says could be true as well tho...it is possible to have it wired where the "peak" is in the middle. imho, it doesn't seem to work as well that way, tho it does work, which is probably the stock intention...put the "wah" treble part in the middle and rock it on and off, contrary to a normal wah wah. i wired mine last nite as a normal wah, which probably accounts for the wiring discrepancy.

Yeah, that would give a "ooooo wahhhh ooooo" sorta deal through the sweep, making it somewhat vocal sounding. But, as you say, when you're used to a regular wah, it would not be very practical. God damn, I've just got to find my breadboard, and rig this up.

[pinkjimiphoton]

i found it kinda annoying to wire it that way, stock..

aha, it's the damn PIN sqwalking!!! now i can fix it!! lol!!

[pinkjimiphoton]

here ya go, the colorsound vocalizer clone and my "Liberal KomradE" mp16b pnp ge fuzzface variant.
both thru a clean amp, little reverb. sorry for the unintentional distortion...it's got some balls.


anyways.. imagine this peaking in the center of the pedal for the possible original config of the colorsound vocalizer pedal.

it's a really nice wah...very phat and very vocally, lot of 2nd harmonic. not a real high range to the sweep, but plenty phat.

anyways...

[digi2t]

OMG BRO!!!   THAT IS PHAT!!!!!

Man, that wah is wicked nice. Like you said, it's got pipes dude. With that fuzz in front of it, it's killer, doesn't matter where you are on the neck. Way up high, ABSOLUTELY BRUTAL!! Imagine that coming out of a couple of Marshall stacks  That'll perk up some ears on f**kin' Mars!

Man, I am soooo proud! Great job bro. I think I'm going to try and make a little work space down in the basement this week, and put one together. I'm stoked now!!

[pinkjimiphoton]

hee hee hee...i knew you'd like it...that's minus the 330 r resistor, into a totally digital amp...so it'll probably scream with tubes!

also, wired as a wah...thinking maybe the thing to do is make it switchable from "formant" with "aaah" in the middle to normal toe down wah.

it is phat as hell tho, ain't it?

and that's with the NEC  replacement equivalent...so  i think you can call it verified if ya want, cuz it definitely kicks some ass!!

[Keppy]

Nice job, guys! That sounds great!

[pinkjimiphoton]

thanks kep!

jerkulator today, then tomorrow i start on the mouthmeister..

[Ronan]

Jimi, that sounds real nice! I need to order some parts. I built a colorsound wah clone years ago after I left my original behind, went back 15 mins later and it was gone. I even wound my own inductor, the original inductor had 470 turns. The vocalizer sounds like it has even better possibilities. Do you have a link to your liberal comrade cct somewhere?

[pinkjimiphoton]

hi ronan,

yah, the colorsound wah is really nice... phat sqwalk!

as for the liberal komrade, just built a dunlop jh2 fuzz, don't put the snubbers in on the transistors, wire the electrolytics and diode (not the clipper) backwards and make it a positive ground circuit.

i used russian nos germaniums, a matched set around 85 hfe or whatever in the sockets.

i'll try and draw you up a layout of what i did later and start a new thread for ya. glad ya like it.
the name was a stretch. how the f"(% do ya say fuzz face in russian? man, i'm glad i just edited my post here before i hit enter.

here's an edit...

go to this page:

http://www.geofex.com/article_folders/fuzzface/fftech.htm

look at the jh2. add an asymetrical diode clipper with 1n34a ge's,  make sure that the 2.2u and 22u caps and the 9.1v zener are reversed, and use the mp16b's, shoot for a gain around 80-100. you should be good to go.