Vox 846 build not working. Wah sound stuck in one position.

Chugs · June 23, 2009, 10:47:13 AM

Hi, for my first ever build I built a veroboard 846 wah based on the Ulysses veroboard layout I found on this site. When I turned on the wah it goes but the wah sound doesn't wah. It sounds like it is stuck in the treble end of the sweep. I have checked the wiring to the pot is correct and even tried a different pot but with the same problem. Any suggestions as to what might be the source of the problem?

panterafanatic · June 23, 2009, 11:07:09 AM

is the board exact? have you googled other 847 schemes? i'm interested in building one as well. pic of the board? (both sides)

Chugs · June 23, 2009, 11:21:03 AM

I used a 56k instead of a 33k and a 2k instead of a 1.5K. Standard Q and mids mods but otherwise circuit exactly the same as the layout. I tried to upload a couple of pics of the build by my camera has decided to stop working for no reason. Machinery has got something against me today.

panterafanatic · June 23, 2009, 11:23:50 AM

mhmm. i have no idea. i'm pretty new to this. is it known to be a good circuit?

Chugs · June 23, 2009, 12:26:14 PM

It's a verified layout so I guess so. VOx 846 wahs sound great.

Chugs · June 24, 2009, 11:21:30 AM

I got it working. I had the polarity around the wrong way on the battery snap. Doh! Sounds pretty good.

Now I just got to figure out how to wire it up true bypass and I am good to go.

Paul Marossy · June 24, 2009, 11:35:54 AM

Quote from: Chugs on June 24, 2009, 11:21:30 AM
I got it working. I had the polarity around the wrong way on the battery snap. Doh! Sounds pretty good. Now I just got to figure out how to wire it up true bypass and I am good to go.

Hmm... that's interesting. I thought that it wouldn't have worked at all with the battery snap in backwards, but apparently it does.

Chugs · June 24, 2009, 07:29:53 PM

Yes, I wouldn't have thought so either. Consequently it took me a while to figure out that was the problem. I have it all wired up now in true bypass and it sounds great! MUCH better than the Vox 847A which I gutted to use as the shell.
I was going to install a Icar taper pot but I might try the trick of changing the 0.22 cap that feeds the wiper of the pot to a 0.33. Apparently this enable standard pots to mimic the old style taper. Anyone try this?

Paul Marossy · June 24, 2009, 07:45:43 PM

QuoteI was going to install a Icar taper pot but I might try the trick of changing the 0.22 cap that feeds the wiper of the pot to a 0.33. Apparently this enable standard pots to mimic the old style taper. Anyone try this?

I haven't tried it, but please let us know how it sounds!

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Vox 846 build not working. Wah sound stuck in one position.