Colorsound Vocalizer vero

[pinkjimiphoton]

has been an honor bro working with you on this. i am so psyched it worked out!! i gotta gig tomorrow, gonna be a long day, i'm on from 2-10pm with two different bands back to back, but will try and get a video cooking on sunday, or at least some sound clips.

it's a very nice sounding wah, when ya hear it, i think you'll be satisfied...the fuzz is not subtle, really, but perfectly blended with the wah sound. kinda hard to describe, to be honest. it's not like a big muff or fuzzface (speaking of which, i just built the "liberal komrade" fuzz, a pnp version of the dunlop jh1 with mp16b ge trannys...REAL nice!!) but kinda like an overdriven sustain. you'll diggit, i'm sure. and i'm sure rg, if he checks in here (poke!!!) will be able to sort out any niggles.

the pot seems to work best that way...if i connect pins 1 and 3, i lose half the wah, but gain a lot of fuzz. weird. looking at the schematic, it looks like you're right, but it seems to work best the way i described..really weird. i started off by wiring it as you described, but it just wasn't right, so i tried every combo i could think of with roach clips and jumpers, and that seemed to be the best.

the only weird thing, is there's a touch of a "bump" sound thru part of the range of the pot...so it may indeed be something amiss.

gonna use it tomorrow, will let ya know how it goes!!

g'nite bro!

[digi2t]

Hmmm... possible mods;

R13 (120K to ground) - Maybe a change, or trimmer, to allow more/less input signal.

R17 (1.2K) - In the schem, pot 2 acts as sort of a voltage divider. Maybe a trimmer here to adjust the voltage being delivered to the tranny.

R16 & R20 - These  may impact the fuzz gain, since the fuzz pot, and pot 1 are interconnected here (pot 1 acting as a variable resistor to ground). The fuzz pot wiper either shift between one opamp, or the other. To my noob eyes, I don't think the fuzz pot really works the gain, but rather the texture of the fuzz.

Then again, what do I know. My initials are D.T., not R.G. 

Goo nite y'all. Good luck tomorrow bro.

[pinkjimiphoton]

that's a good way to put it...fuzz texture. that describes it alot better than i could!!

i hear ya, i'm not dt, or rg, i'm jp, and man...i'm amazed every day by the stuff on this forum!!

sweet dreams bro, catch ya tomorrow or sunday..peace!

[soggybag]

If you haven't thought of it already, be sure to play with the rotational position of the pot. Since the pedal probably doesn't rotate the pot through it's entire range, you'll be able to adjust it a small amount one way or the other.

[digi2t]

If you haven't thought of it already, be sure to play with the rotational position of the pot. Since the pedal probably doesn't rotate the pot through it's entire range, you'll be able to adjust it a small amount one way or the other.

Good catch soggs! Just like the Phase II pot. You've got some travel left at either end that you can lean to.

[pinkjimiphoton]

believe it oor not, this thing is using pretty much the entire pot's travel..i could turn it down just a little bit if i wanted, but not much. i have it set right now so toe down hard is as full treble as possible, don't really need more bass...it has plenty!!

[digi2t]

I've been looking at the TL074 chip as well, and I'm thinking that maybe I'll do a second vero to accomodate it, instead of the RC4136. I have no idea what the result will be, but I think that the TL074 is more readily available, and cheaper.

Another mod as well could be to swap out the CA3080 for an LM13600, and create 2 alternate tranny circuits. Then use a DPDT switch, one side for the line coming from point 12 of the RC4136, and the other for the blue wire going to the pot. Then you can create  a circuit as per the original, and a second circuit using a different tranny, diodes, etc., and switch between them.

Definitely something worth breadboarding.

[pinkjimiphoton]

i tried tl072, 071 and 082 in the socket, none worked. they DID make a difference stacked on top of the original chip tho. the original is hard to find, that's why i went with the nte replacement, tho i did order the original on ebay...when it comes in, i'll try it out and see if it works.

off to the gig, bro...talk soon.

peace!

[ORK]

You are aware of the fact that the RC4136 is the IC with a differing pinout from the usual quad-standard?

[digi2t]

You are aware of the fact that the RC4136 is the IC with a differing pinout from the usual quad-standard?

Yeah, that's why I would have to shift some thing around on the vero.

i tried tl072, 071 and 082 in the socket, none worked. they DID make a difference stacked on top of the original chip tho.

Those won't work because they are jfet op amps. This requires an operational transconductance amplifier (ota). The LM13600 is a dual ota, so you could use half of it, or like I mentioned above, create a parallel circuit, and switch between the two.

I've been studying a gut shot of the pedal, and I'm wondering if the pedal pot wiring is correct on the schem, especially the purple wire. From the picture, it really isn't clear if it does jump to both 1 and 3 of the pot. There is a bare wire, that runs around for ground, but I can also see it running by the pot terminals, as if it was a jumper. My question is "why would they use a bare wire as a jumper, and risk a short to ground?". Maybe the purple doesn't jump. Maybe it's;
Purple - Pot 2 - term.3
Blue - Pot 2 - term.2
White - Pot 1 - term.3
Grey - Pot 1 - term.2
and leave terminal 1 on both pots open.

Have a look;


It's tough to make out.

Also, I'm wondering about the PNP tranny. I mean, this is a neg. ground pedal. I'm just not up to snuff yet on that one. Oh noob is me!

[phector2004]

Hey guys, great work! I've been following this thread for a few days now and I'm glad to see how far you've gotten  

Hope you get the wiring sorted, but here's something odd I found:



Looking at this picture from the gallery, the mysterious jumper isn't there... hmm
It looks soldered in that last pic, but this one seems to have Digi2t's new wiring scheme (with open 1's)

Maybe the jumpered one's been tampered with/"repaired"?

Best of luck,

Phil


EDIT: Oh and why use a germanium transistor? It's not in the signal path so it doesn't need to soft-clip or anything!

[Keppy]

Looking at this picture from the gallery, the mysterious jumper isn't there... hmm
It looks soldered in that last pic, but this one seems to have Digi2t's new wiring scheme (with open 1's)

Look again. The bare wire above the top splits from the junction to pin 3 of the pot (you guys have been calling it pin one...I think you have it backwards, unless I'm much mistaken. Check the FAQ here: http://www.diystompboxes.com/wiki/index.php?title=DIY_FAQ#POTS).

Also, the photo's a bit compressed and grainy, but if you zoom in you can see another bare wire jumper between pins 1 & 3. This photo just has a more straight-on view that causes the wire to disappear against the background of the pot terminals. I don't know anything about this circuit, but I can see that lug 1 connects to lug 3 connects to ground.

[phector2004]

I'm not seeing the jumper in the pic I posted... I see a wire coming from the ground bus thing grounding the pot case, but that's it...

And yeah, it is pin 3.. whoops! 

It might also have the purple wire connecting lug 1 to the pot case. Looks kinda messy there!

[Keppy]

I had to zoom in to (sort of) see the jumper. Like I said, it's pretty much indistinguishable from the lugs behind it, but if you look between the gaps you can see it, though things get pretty pixelated once you zoom in that far. It's nothing that would hold up in court, but I think I see it. A less-compressed JPEG would show us for certain.

I guess I should point out that the jumper I think I see travels straight over the middle lug on a very short route, unlike the one in the clearer photo that arcs up past the lugs toward the body of the pot. You really have to look in the spaces between lugs to see it. Unless I'm crazy, which is entirely possible at this moment in time.

[digi2t]

I'll have to differ to the "go to" expression used by most baseball umpires, when a situation gets convoluted....

"I didn't see it".

I don't see it, and since Jimi's got one up and running, maybe he can try it, and report back.

[Keppy]

Took a closer look, and now I'm less confident. Here's what I was looking at, though.

Note the shiny vertical bit just to the left of the cursor:


That shiny bit is missing on the other gang of the pot:


Looking closely again, it could just be the way the light reflects of that part of the pot at that particular angle. Or it could be a jumper, though on this closer inspection I can't say with confidence that whatever it is goes all the way to lug 1. Whatever it is, though, hopefully now at least you can see what I was looking at.

Maybe I should stick to pedals designed by drummers. 

[Ronan]

There is a jumper there, from 1 to 3, I found another slightly better version of the same image this morning, and was going to post, but thought it was not that important. Now I can't find the link, I thought it was in the aaron nelson gallery but maybe not. But yes, I see the jumper too.

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.

Great thread, I want to build one. Been following this with interest. Big mystery as to what's going on, as I believe jimi know's what he is doing, and the schem looks correct as far as I can tell. 

[phector2004]

Hmmm good point... maybe the 12k, 3k, and 2.2k connected to the tranny need to be adjusted for non-ME.0.49 transistors? E.g. maybe a 2N3906 or a 2N2907 would do here if those values were played around with?

[pinkjimiphoton]

hi guys, i'm gonna try and play with the wiring today a little and see if i can get it working right.

i DON'T know what i'm doing, i'm a total newb outside of building a few things, but i've had fairly decent luck so far.

i tried silicon trannys, made no difference...worked about the same. no tonal difference.

the treadle seems to connect/disconnect the transistor almost, if i pull the tranny out of the socket and then touch it to the socket terminals, it wahs.

right now the transistor i'm using is a russian made mp16b ge pnp with an hfe of 135. that's the hottest one i have.

i think there IS a prob with how i've got it wired tho, so gonna go back to the original now that i clipped that 330r out of the circuit.

tried it yesterday between sets, it sounded great on peet'd gibson sg, but there's a "knock" sound part way thru the rotation. maybe a bias problem, or maybe even why they don't make 'em anymore <g> or most likely cuz i have the pot miswired trying to get the circuit to work right.


we'll see..gimme a little bit, i was on yesterday from 12-12 emceeing and playing at my friend's 70th birthday party, and i'm kinda ToAsT right now..

[digi2t]

right now the transistor i'm using is a russian made mp16b ge pnp

I dunno bro, but my research shows a lot of confusion as to the polarity of the MP16B. Some say PNP, but I've found many pointing to NPN. Even on Ebay, some say NPN, and some PNP. It's about a clear as Mississippi mud!

The pot would vary the base voltage from that 1.8V max to around 1/12 of the 4.5 volts available = 0.375V

OK, we seem to have concensus on the jumper, and I really respect the hell outta the Kep-meister, so I'll say there is a jumper there. The tranny is probably whats creating the hiccup here, since we don't have any specs on it. Since the numbers generally don't lie, I guess the best way to slice and dice it here would be to put 3 multi-turn trimmers in there instead, set them to the schem resistance specs, and then read the tranny base voltage. Then you could swing the trimmers to line up the tranny, so to speak.

On another note, I've been scouring the net vis-a-vis ME.0.49, including ME049, and ME-0-49, and I've found references pointing to the following PNP transistor; BC212 (BC212-ME049)

The 2N3906 specs are similar, but I believe the BC212's Vbe(on) is just a tad lower, looking at the specs.

I dunno, just a shot in the dark....