Topics

Hi guys, I'm stumped.

First off, here is the schematic that is closest to what I have here:

https://www.pcbway.com/project/shareproject/ZVEX_Super_Duper_2_in_1.html


One transistor is just not biasing properly.

Side 1 is the one I am having issues with. It is sputtering like it is starved for voltage - which as you'll see, it is. I have pulled all the resistors up near it and they have all measured fine. I thought maybe the transistor had failed, so I replaced it, and the voltages are the same.

Here are the voltages I am getting. They are taken with the gain controls (C5K) down:

Side 1
D - 4.8v
G - 1.64v
S - 4.1v

Side 2
D - 7.2v
G - 2.69v
S - 1.83v

I have 9 volts at the front side of both 5k1 resistors, but then the voltage drop across the 5k1 resistors coming from the power rail is:

Side 1 - 4.33v

Side 2 - 1.93v

I have tested the diodes and they seem to have a reasonable voltage drop across all of them.

It is just not making any sense to me. What else could be causing this voltage discrepancy.

I've been getting my toes wet building again on and off for the past few months, and I'm starting to need some stuff. Where is everyone buying parts at now? I still use Mouser for my caps and resistors and such, but I need things like transistor sockets, vero board, etc. Small Bear doesn't seem to have the same selection they did before they were bought out, and I just flat out can't remember the other shops I used.

​Well I've been snowed in again for 2 days now. 140 something inches this year. I've had this Power Wah for several years now, I just never got around to getting it fixed.

It would turn on, but it was farting out like it was starving the transistors for voltage. I could get a small response changing the light to the LDR, but those transistors were just being starved. Most notably the photocell that it uses as it's variable for the wah had pieces missing off of it (pictured).

I pulled data sheets for the transistors up, and they just weren't getting the voltage they needed to turn on and off properly, so I ended up having to pull out every resistor and check it for tolerance, and I ended up replacing 2 of them - a 220k, and a 4.7m. I replaced some capacitors, though I don't think those were needed (I do need to trim and finalize placement of the last one pictured). To finalize the fix, I need to order the correct sized resistors, it looks stupid having some 1/4w in there. I have no idea what I am going to do about the shade that goes over the LDR as it was missing when I got the pedal. It doesn't affect the sound, though it does affect the range of the sweep.

But crap, this thing sounds amazing. If it weren't so huge, and needs it's own 120v power, I would be putting this thing on my board for sure.

Can you guys show/tell me what you use to store all your parts? Resistors, caps, etc. I had used plastic shelves with the tiny cubbies in them, but I just don't have the room for them any longer.

Well, I'm going to try to get back into this stuff. Life happened - a move spurred on by a 3rd kid, so I lost my workspace, etc. I've just dug out all of my old stuff including digging through my hard drive finding all the schematics I had tried putting together on my own - I seem to remember having more than 2 complete ones, but that is all I could find, oh well.

Anyway, glad to be back, its been a few years.

I just bought a not working unit on Reverb for a good price. I for some reason cannot come across a schematic for the thing. Anybody have one laying around? It is just the Wah, not fuzz, or volume. Board revision RW1-B. I know it has to be out there someplace, my google-fu is just failing. Thanks fellas.

Hi guys, things have been crazy lately, so its been a while since I've posted, or even done anything. But, I made a deal with myself, that I'd have a finished product to try to get into the local music stores by this summer. I've had the board designed and built, etc for a long time. So I freshened up the artwork, added a logo, and had some enclosures professionally done, since I can't seem to get a good etch to save my life. Anyway, here it is. There are a couple of small things to tidy up, like the final color of the LED, I can't decide between white and red. Also the knobs, I think I like these best, but want them to be slightly larger. It is going to the owner of a local store on Monday to test for a week or so, and he's going to let me know whether he'll carry them for me. Here's hoping.

I finally finished the new board, and an etch I did. The only thing I used that I didn't put together was the 3pdt board (thanks Ben from rullywow).

Boy has this been a learning experience. I originally had this measured out for a 1590b but forgot to measure it vertically. So I had to do a 125b. It's slightly too big. I might pick up a few of Peter from vfe's new Hammond size as that would be perfect.

The etch still needs work, and I need to find some bitchin knobs. But I'm pleased otherwise. Fired up first try. I got a bag of 1k pn3565 on ebay, so I have those in with some 2n3565s to see the difference. I can't hear any. The hfes match as close as I can and the sound is indistinguishable to my ears, which is nice because now I don't have to spend $3 each!

What did I do wrong? The print didn't fully transfer. I left the iron on for about five or six minutes. More time? I soaked it in water afterwards. What do you guys think before I use up another sheet of paper.

Well I've spent a lot of time with this circuit now, and ive decided I just don't like it very much. I can't tame the noise like I want. It sounds cool at lower gain, but squeals at higher. It seems it either wants to be too gated, or squeal. Oh well. This was more of an exercise in playing with a circuit and designing and building my own board for it. I had the boards made at elecrow, and they are nice boards.







His cigarette gets brighter with another of the sound 2 light boards I got. The envirotex pour didn't come out well because the decal lifted underneath and made it wavey. Oh well, I'm gonna try my hand at etching. Decals are just too finnicky for me.

Alright, so I liked the retrograde so much I thought I'd use that as the project to learn Eagle, and try to make it my own in the process. I made a few tweaks to the circuit, though nothing major, and I haven't settled on which values I'm going to actually end with. I gave it a couple of switches to swap between different diodes in the octave section, and different transistors. I found some GE NPNs that I'm going to try in it. I haven't seen any of these with GEs, but who knows, maybe there's a reason for that. I'm missing 2 switches that haven't arrived yet, but should tonight, so I'll be able to test it with the GEs in it.  Dminner made the enclosure, and it is super awesome. With the space theme I thought it would be cool to put some glow in the dark paper underneath the envirotex, so we'll see how well that works. It lit up real nice with my UV LEDs on the breadboard. I also made a little "planet" to hide the LEDs.



Here it is with envirotex and all the holes for LEDs. I plan to put 4 LEDs on the left to act as stars, and then when the octave is engaged, I have a sound2light board (I'm sorry I can't remember which of you made it. chromesphere maybe?) to run the UV leds to make the glow in the dark paper hopefully sparkle. We'll see.



The board is bigger than it needs to be, but its my first one, and I'm still learning how to lay these out.



I've since populated the rest of it, but its got all kinds of wires going every which way and it looked ugly, so here it is in the flesh.



Its been quite the time consuming project with making the PCB and all, but its been fun, and boy oh boy did I learn a lot. I'll update with finished pics as soon as I'm done with it.

I've been playing around with eagle this morning, trying to lay out a board. I cannot, for the life of me, figure out how to make smaller movements to individual pieces on the board layout section. The board I'm setting up is 18x18mm, so fairly small. The parts just jump the entire way across the board. Is there a way to move them in smaller increments?

Humble Bundle has a ton of electronics books right now, and Make electronics is one of the ones you can get for $1. Quite a few more, but you have to pay upwards of $15 for them. It is in .PDF but considering that it goes for $30 on smallbear, its a pretty good deal.

https://www.humblebundle.com/books/make-electronics-book-bundle

I bought a huge bag of carbon comp resistors off of ebay. Some of them read dead on with my multimeter, but some of them, which are 5% are reading double, to triple that. The worst offenders are a stack of 6.8ohm that read anywhere from 7.4-7.9. I'm thinking they're just really poor quality, but even so, that surprises me. Is this just carbon comp? I'm not super worried about using them, just surprised at the difference between the seemingly same value resistors.

So I had an idea for a finish when I found some blacklight leds on amazon. So I want to do kind of a star background so when you kick the pedal, it all glows. What havs you guys used paper or sticker wise for that? I'm not exactly sure what would react to blacklight like I want.

Has anybody used this app yet? Seems really cool from what I've used so far. It'll be nice to have something I can tinker with on my phone when I'm not at my computer.

https://play.google.com/store/apps/details?id=com.theophrast.droidpcb&hl=en

I forgot to post a new thread with my 2015 builds. Nothing special, I started building around the beginning of the year, so these are all definitely noob builds.

Here is an Acapulco Gold clone. I liked the build, it was my first vero build, and the circuit is great. I need to build another, as I bought enough for 2, and hopefully I can dial out some of the things I don't like about it. This has an added gain pot, too. I've since bought some with connected rows, as I'm wondering if some of the problem is I'm missing a connection someplace since I only had pad per hole. I'm almost positive that's my problem, actually. I put the art together with clipart I found in inkscape. I ended up having to change the knobs for slimmer ones because the "gain" label was covered up by the one I had on there. Measure better next time.











Next up is a Retrograde and a Fuzz Face from Pickdropper (he makes awesome boards, btw.) This one was very unintentionally messy. I didn't plan it out properly and the wires ended up everywhere. It all works, and sounds great. I've since bought 5 or 6 different types of PNP's for it, and have the fuzz face dialed in really nicely. I also moved the bias knob off board, as the circuit has a trimpot spot for it.









At that point I wasn't brave enough to try for any sort of finish, so bleh.

Last up, or first I should say as this was my first official build, is a weener wah.







That's everything from last year! Here's to more, and thanks to all you guys for all the help.

This took me an insane amount of time. I had to redo the enclosure once, repaint it probably 4 times, and I kept ordering wrong, or forgetting things. Needless to say I learned a lot. I had enough room on the bottom to move my test rig into, so now its kind of an all-in-one rig tester.












My envirotex pour came out really nicely I thought:



I have each row with individual breadboard jumpers so that I can have as many as 5 pots at a time. I'll never need that many, nor will each row necessarily line up to what I need, but that is okay. The wires are messy, and I have some ideas on how to clean them up, but for now the book is closed on this one. All in all a really fun build, and thanks to Leevibe for sharing his OSHpark boards for this.

I painted it too dark the last time around. I was in a hurry to get it done, and it started snowing on me, and I just was too heavy with the trigger finger. Here is how I intended it to come out; much more visible than what I ended up with:


(That was my first attempt before I figured out my envirotex pour was too soft.)