Problem - first build - Vox Zoom Distortion

[lborl]

This is actually a joint first build with a Devi Ever Soda Meiser that I can't get working either, but since I'd overcomplicated that with switchable transistors and a momentary 'chaos' switch I figured I'd build a simpler circuit to boost my confidence before I start properly debugging the first one. Predictably the simple thing doesn't work either.

http://tagboardeffects.blogspot.co.uk/2013/01/voxguyatone-zoom-distortion-box.html

Now, my soldering admittedly isn't great, but I've installed pickups in my guitars before without problems and the pedal does seem to be 'working' in bypass, so the soldering can't be completely hopeless: I don't see any obvious solder bridges but I've tried scoring along the tracks between strips with a knife and hot iron point.

I've just been looking over the build instructions again though and there's one thing I may have misinterpreted - I hope so because then it might be an easy fix. There's a wire running to 'Output 1/Dist 1&2'. Now, even though I know "/" usually means "either / or" I figured in this case it would had to go to all of those, so I took that wire to Output 1 and then bridged another wire from Output 1 to Dist 1, and added a jumper between the lugs of Dist 1&2. Please tell me that was stupid and if I change it it'll work?

[Hozy31]

That seems correct to me. You have got output 2 going to the 3PDT i presume? And you are using this offboard wiring http://tagboardeffects.blogspot.co.uk/2012/02/offboard-wiring.html

[Ciaran Haslett]

No such luck with the "easy" fix I'm afraid.  On all these layouts, if multiple connections are specified, they will be written with "/" or "&."  You've done that part correctly.

To help debug your build we need voltages at each IC pin.  This will give us an idea as to where you have a problem.  Set your multimeter to measure DC.  Place the black probe on the ground/negative lug of your battery or power supply, touch the red probe to the positive lug of your battery/power supply.  This should read somewhere close to 9 volts.  That verifies you're using the meter correctly.  Now keep the black probe where it is, and touch the red probe to each IC pin and record its voltage.  Take care not to short adjacent pins with the probe.  IC pins are numbered 1-8 starting top left and going anticlockwise.  Post the voltages here.

Then hi res pics of the component side, copper side, and ALL wiring.  You can post here or upload to an image hosting site and post the links here.  Try to take photos in good light that clearly shows the resistor colour bands and preferably looking straight down.  This ensures that taller components are not obscuring some connections.

99% of all trouble builds are either misplaced/wrong valued components, solder bridges between tracks, missing/partially made cuts or misplaced wiring.  Give it a thorough going over again and remember, this isn't a race!  The excitement to get it finished can quickly turn to despair if it doesn't fire up first go.  It's hateful I know haha.  But the more care care you take when building, the better chance you have of making a working circuit.  So just take your time.  We have all been where you are now.

So...have another look and post some voltages/pics if you see nothing wrong.

Good luck and welcome!

Ciaran

[lborl]

Hey, thanks for the replies. I did the voltages thing you recommended and came out with something like these readings:

9v test (battery) - 8.52

IC pins
1 0.00
2 4.01
3 1.72
4 0.00
5 0.00
6 4.21
7 8.43
8 0.00

I reflowed all my solder joints on the board and then tried the 'audio probe' thing and was quite surprised to find there were several points in the vero that I could literally park the probe in a vacant hole and hear the whole distortion working. After that I started messing around with crocodile clips and found I can actually get the box three-quarters functional by just shorting Output 2+3 - obviously with output then fixed at full (which is way too loud with Distortion maxed).

So I figured I must have cacked up soldering the pot and somehow fried the wiper something, but today I've just tried installing replacement pot number 3 very carefully and I'm still getting the same problem after.

Incriminating photos:

https://www.dropbox.com/s/ow7284zxoaptoax/2016-02-18%2002.10.03.jpg?dl=0
https://www.dropbox.com/s/alhadrq8aogch1h/2016-02-16%2017.37.22.jpg?dl=0
https://www.dropbox.com/s/6dd0p0r47tamkvw/2016-02-22%2012.30.07.jpg?dl=0
https://www.dropbox.com/s/0kkxsgzpxzaurtm/2016-02-16%2017.38.08.jpg?dl=0

[Beaker]

Hi Luke and welcome to the forum.

Soldering, like any other skill in life, is something you get better at the more you practice it, Soldering pedals is hard for a beginner, with so many different components and materials to deal with. We all started off badly, and we all get much better with time and practice.
As beginners we all tend to rush things, when we should slow down and take things slowly and carefully. When I was a toolmaking apprentice, I had a couple of mantras drummed into me, that still hold true. "Do it right or do it twice" was the main one. Point being, take your time to get it right first time, or spend twice as long correcting it or starting again from scratch.

With that said, please don't think I'm being harsh when I say your soldering is... not good.

Your board soldering is not too bad at all, and I can't see an obvious problem, but frankly, your offboard wiring is very poor - and this is where I think your problems lie. I will break it down into points.

#1. What kind / wattage iron are you using? I ask because your jack connections look to me as though your iron is not man enough or hot enough for the job. You need to reflow all the jack connections, so that you have clean joints on the solder tags.

#2. Snip of the excess wire under the tags - yours are so long they look like they could be shorting on the jack barrel - if they are you will short your signal to ground.

#3. Did you solder your pots with them fixed in the enclosure? (It looks to me as though you did). If you did, that's a bad move - especially if you soldered wires to the pot holes rather than the lugs. It's easy to poke too much wire through, and short the pot lug to the enclosure.
Use the lugs instead of the holes - less chance of spitting solder into the pot case.

#4. You have no insulation on your LED wire - you need it to prevent short circuits.

Again, I hope you don't think I'm picking on you, my early builds were utter shite, so I know how frustrating this all can be.

Take a look through the "Show your pedal guts" sticky thread. Yes it will make you jealous (it still makes me jealous), but it will give you loads of cllues as to how to go about wiring up your pedals your pedals effectively and beautifully.

[Ciaran Haslett]

Well your voltages look good.  If it works when you link Output 3 to Output 2 then that pretty much eliminates the board as being the problem.  So your issue is either the pot itself OR your off board wiring or footswitch.

Try the following...

1. Confirm Output pot lug 1 is connected to ground.
2. Remove Output pot lug 2 wire
3. Put your Audio probe on lug 2
4. Try turning the pot up and down.  If the volume changes then the pot is fine.  If not, then the pot is shot.


Then test your footswitch.  Use Continuity mode on your DMM and make sure all the lugs connect to where they're supposed to AND that the internal connections are working.  The middle lugs on the switch are the common ones for each column.  So when pressed, the middle lug on column 1 would connect internally to the top lug.  Press again and it connects to the bottom lug.  Test this for each column.  Bear in mind that you've made some links on the switch itself....the input lug (9) is linked to lug 4 with a piece of wire, so when the switch is pressed lug 9 should connect to 4 AND 8.  When switched again 9 connects to 4 and 5.  So keep an eye out for things like that.

I'd also agree with Beaker.  The solder joints on your jacks look more like they're "sitting on top" of the lugs than "becoming one" with the lugs.  These kind of joints can be unreliable.

After all the above I would concentrate on the off board wiring.  Make sure EVERY connection is really going where it's supposed to.  Use your DMM in Continuity mode and confirm every wire isn't broken, that the lugs of all pots are electrically connected to the right places etc.

You'll get there in the end.  We've all been there.  Good luck