anyone built this and had it work? i noticed the web site hasnt been updated in 5 years or so.
i have a few ?'s
1. the axis wah from http://fuzzcentral.ssguitar.com/axiswah/axiswahlayout.gif doesnt have a output shown, but if you look at the buffer http://fuzzcentral.ssguitar.com/mccoy/bufferlayout.gif it has a signal coming from wah 3. if i rem correctly the signal from the original cry baby came from wah 2 right. is this wrong or is it wired differently? building and output buffer http://fuzzcentral.ssguitar.com/axiswah.php says you dont have to have it but it helps when hooked up to a fuzz face. mine doesent work. im thinking the wrong wah tab is hooked up to the output signal.
2. i subbed the bc109c's with 3904's. if the above is correct then this is the prob.
any suggestions
if you look at the schematic of the vox Clyde McCoy wah the output is coming from lug3 of the wah pot. same as the axis wah. since the opposite lug is going to ground you shouldn't get signal from it. try using the one opposite to what you're using now
you mean lug 2 right? thats what i was thinking.
lug 2 would be the wiper, this is not the output on a wah like the axis/crybaby/vox. 3 would be the uppermost lug on the pot in the schematic. if that's the one you mean, then yes, unfortunately there's no standard numbering of the lugs on pots, which makes them harder to learn than a transistor, or IC which have names/number for pins
(http://www.theguitarfiles.com/spaw/images/lib1/ECB24B.jpg)
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=218&g2_serialNumber=2)
hopefully having these pictures will clarify. the blue wire is the output in both diagrams, shows where output is in the scheme and how to wire the pot. that is where you need to send signal to the buffer from. if that doesn't work then you need to take voltages and make sure you have pinouts right on all of the transistors/fets. i know i recently spent way too long trying to troubleshoot a build and the problem was that i had the pinout on the fet wrong, and was getting no sound.
dang thats how i have the hot pot hooked up. so the hot pots arent numbered the same as regular pots, that sucks. i found an old post from 2006 from here that said you could sub the bc109's with 5088's. so i changed out the 3904's with those. maybe the layout is diff with the 5088's. this pedal cannot be this freakin hard.
well people liked this pedal and it worked in 2007 (though with some tweaking) ill post some pics this afternoon
sorry i had to find the cord that hooked the camera to the comp.
the wah pot ill number like a reg pot. left to right. 3 wired as output, 2 input, 1 ground. on the pc board. left to right, input, wah 2, wah 3, 9v+, ground.
(http://i434.photobucket.com/albums/qq63/trout-lips/MeckandElli123.jpg) (http://i434.photobucket.com/albums/qq63/trout-lips/MeckandElli124.jpg)
(http://i434.photobucket.com/albums/qq63/trout-lips/MeckandElli125.jpg) (http://i434.photobucket.com/albums/qq63/trout-lips/MeckandElli126.jpg)
hope these help
bump
sorry, I'm a fulltime work/college guy so I'm late getting back. looking at your pics i see that you've made sure part of your board isn't grounding out on the enclosure, however your +9V wire doesn't appear to be insulated, and could be grounding out on the enclosure, which =no sound. did the circuit work outside of the enclosure? if it did then that is the type of thing i would look at. if it didn't you really need to get your voltages, check for bridges/cold solder joints, etc. if i have time tomorrow after class I'll try to get voltages from my wah which works. they may not be exactly where yours are, but if yours is working properly then they should be close. did you make the separate board for the buffer? i don't see it, and if it's in there then that may hold the answer as well. another thing is to make sure you have the proper resistor values in there, which i can't really make out from your pics. looking at the scheme this should be a really nice wah, so hopefully it's something easy to fix.
QuoteQuote
MPSA18 (This is the one in the middle of the schematic)
C 7.69
B 1.08
E 0.69
Not too bad. I'd like to see the base and emitter be higher and the collector lower.
Quote
MPSA18
C 8.40
B 1.29
E .83
Not horribly bad. I'd like to see the emitter be higher, up at a couple of volts.
this was in another thread about a diy jh-1 build, just to give an idea. the comments on the voltages are made by RG, so i would trust that. i will still try to check min for you though to have them from a working unit.
its ok Kris. im a part time student. studying seems to about the only thing i get done lol, i havent built the buffer yet. i was waiting on parts.
i checked my trannies and i was getting 8.41 or about on the ebc of both the trannies.
i dont understand the uninsulated 9v+. ive got it hooked up like ive always dont it.
q1(closest to output wires) battery-8.89
e-8.45
b-8.39
c-8.89
q2
e-8.46
b-8.45
c-8.87
these are not neg
so ive got a prob somewhere
yeah, with voltages that close together on all pins, i would check resistor values and for bridges around your transistors an +9V trace. give me a while to get my voltages for you, it's homework time right now...
ive scrubbed the board with hydrogen peroxide. ill check the resistors
I would say that if you are going for the vintage sound, 5088's are going to be too high gain. According to the FuzzCentral info on the Clyde McCoy wah, transistors in the 350-400 hfe range are the best with the original circuit to get vintage sound. That's why BC109B's are usually suggested, as these are BC109's that are sorted into the medium gain range, and are most likely to be in the 350-400 hfe range that other higher gain trannies. One of the reasons that the modern production wahs (like the current CryBaby's) don't sound like the vintage ones is that they use very high gain MPSA18 transistors. If you don't care about it sounding like the vintage wahs, then 5088's will be fine. Just a thought.
Al
Adjust the operation points of Q1.
http://fuzzcentral.ssguitar.com/axiswah.php
see the 100K resistor by the 4.7uf cap. You can adjust that up and down in value to shift the operation point of both transistors. Measure the collector voltage of Q1 change the resistor value measure again note the sound change.
The gain is controlled more by the ratio of the collector to emitter resistor than by the transistor hfe. So if you want to tune it you can shift the operation point and gains with the 100K and/or emitter resistor and adjust the gain with the series input resistor.
The gain of Q1 circuit is a big part of the "sound" the more the gain(as long as there is enough current and the circuit is not clipping) the greater the voltage out of the wha pot wiper to sweep the filter part. The wha pot is like a volume control
i used the 5088's bc i didnt have any bc109's. i bought a multi pack that was supposed to have some in it but it didnt.
im not getting any sound. if kris is right ive got 9v+ bleeding into my signal somehow. ive scrapped the flux and scrubbed the board with peroxide. there shouldnt be anything touching but there is somewhere.
Quote from: clamup1 on January 22, 2011, 08:49:30 PM
i used the 5088's bc i didnt have any bc109's. i bought a multi pack that was supposed to have some in it but it didnt.
im not getting any sound. if kris is right ive got 9v+ bleeding into my signal somehow. ive scrapped the flux and scrubbed the board with peroxide. there shouldnt be anything touching but there is somewhere.
If you buy unsorted BC109's, there's a big chance you'll get ones that are either too low gain or too high gain to be in the recommended gain range for a vintage wah sound. As I said, the reason BC109
B's are suggested is because the "B" version is sorted into the medium gain range. So even if the package had some BC109's in it, they could be higher gain like the 5088's. It's not the type of transistor that is important, just that they are NPN in the "good" gain range. And yes, you can make up for higher gain transistors by changing other component values in the circuit, but this isn't necessarily going to get the vintage sound, as the Dunlop Crybaby's can attest to. That's what they do to adapt the circuit to the higher gain transistors they use. Just like a Fuzz Face sounds best with certain gains for the transistors, a wah sounds best (IF you're going for the vintage sound, which I don't even know if you're trying for) with medium gain transistors. I know you're having other problems with making yours work, I was just mentioning this in case you want a wah that sounds like the old Voxes. In my case, I was trying to recreate the sounds I got in the past with the Clyde McCoy wah I had when I was a kid, and I found that keeping to those guidelines for the transistors was one of the keys to getting that sound. I would never have sold that vintage wah had I known that the Crybaby's and such in the future were going to sound as bad as they do.
Good luck, I hope you iron out your problems with the wah,
Al
zombiewolf- oh no im going to try to get as vintage as i can. i broke out a SRV album i have and heard voodoo child. i got motivated to try to get my wah to work.
can anyone look at the pcb layout and see if there is a electrical mistake somewhere that wont let it work? im gonna make the buffer this afternoon and watch football. great combo lol
Did the wha work at one time?
All the transistor pins measure about 9VDC? Did you measure with a plug in the input jack? Where was the neg DMM probe placed? (case? ground trace on the PCB, neg of the battery?)
I would check for a missing ground(s) connection, a DMM has high input resistance so it does not load down the circuit that much. I would start at the input jack
disconnect the battery
set the DMM to Ohms insert a plug in the the input jack to complete the ground circuit
Check all the ground nodes to make sure they are all connected
i had the neg attached to the pin the neg from batt attaches. yeah it worked with the original board. i did something to it and it quit working. so i made this one. im hoping the wah pot or what ever the thing on the left side of the board is, didnt fry or quit working.
Clamup1
Did you check the connections and read what I posted? You only gave one answer. If you checked at the - battery without a input jack to connect the ring and sleeve you could get readings like you posted.
I posted things to check it reads like a possible open ground to start
Does it pass signal in bypass?
Also I checked the link at the bottom of your posts.
https://sites.google.com/site/garagebandeffects/
I saw payment, you build for money?
Q1
E.05
B.63
C4.38
Q2
E3.58
B3.99
C8.12
Voltage after the 1K resistor in line with the 9V path is 8.49V with 9.4V coming in from my power supply.
from my functional modded crybaby, should be close to this for working voltages. when i say your 9V wire isn't insulated, i mean i see a piece of cardboard between the wah shell and board in one place, but your 9V wire isn't insulated, so it could be grounding out on the enclosure. try to get the circuit working outside of the wah shell to isolate this type of problem.
@gus- i havent checked the ohm thing yet. do you put the neg probe on a neg ground area? and probe the other ground points with the pos?
i would like to start building for money. i havnt done any kind of advertizing other than the sig on the bottom of my posts. as far as i know there isnt anyone within a 50 miles of where i live that do this so i should do pretty good. except for wah pedals that are aggrivating as hell
@kris- im getting almost the same +pos # on the ground. the only thing i can think of is a bad resistor or cap. there are two res and a cap going to ground.
ill check the ohm thing and see what i get.
Quote@kris- im getting almost the same +pos # on the ground. the only thing i can think of is a bad resistor or cap. there are two res and a cap going to ground.
that and check with a meter for no other possible bridges. it can be hard to spot them sometimes. i spent 2 days trying to figure out why my tremulus lune had fluctuating power instead of a solid 9v reading, then i saw a wire from the LFO touching something it shouldn't have...just sayin'.
this must be the April Fools wah. im getting + in the ground and there is no way. there are no solder bridges and nothing is touching. it might make better target practice than a wah
then i would start checking all of your resistor values with a meter, double check cap values, and pull out my hair while i cussed loudly in my garage!
lol sorry.
i changed out the resistors and the 4.7uf cap going to ground.
im gonna rewire all the grounds and see what that does. if there is a bridge its miniscule and cant be seen with the naked eye.
@gus- i was getting almost the same values with the jack in. i need some assistance with measuring Ohms. do you put the neg term on the ground of the pcb and probe the rest of the grounds with the pos probe?
@Kris- i pulled hair and cussed, hopefully i dont have any bald spots lol
Quote@gus- i was getting almost the same values with the jack in. i need some assistance with measuring Ohms. do you put the neg term on the ground of the pcb and probe the rest of the grounds with the pos probe?
put one probe on a known ground, then make sure all your other grounds are connected using the resistance part of your meter. should be 0 ohms between all your ground connections.
ive got 15ohm. so i have an open ground somewhere right?
i resolderd all my grounds and at one point i got the resistance down to 10. then scrapped the board with a exacto knife and now its back to 15. i dont know how that works