Vox wah wah mods

[Spencerleehorton]

Well I’ve put in the output buffer and put guitar into wah wah then fuzz and then wah doesn’t work, the other way fuzz then wah second wah works fine?
I was under impression that an output buffer sorts out the wah in position one?
I will also try a buffer from a tuner and see if that sorts it?
The other mods to the wah I’ve tried have definitely made it closer to what I like but I will put some trimmers in and dial in the notch a bit better along with the width of the filter

 

[Whoops]

Well I’ve put in the output buffer and put guitar into wah wah then fuzz and then wah doesn’t work

When you say "doesn't work" are you saying that it sounds bad or that there's no sound at all?

 

[dai h.]

FWIW, the Fulltone '69 pedal (their version of a Fuzz Face with tweaks) if memory serves has a 50kB pot (wired as a variable resistor) right at the front--maybe something to try.

I've tried wah then Fuzz Face with a very simple ordinary FET buffer and the pickup simulator circuit (on Jack Orman's AMZ site) with a couple of inductors (a wah inductor, some very small cored one, and a (driver transformer?) from an old Sony tape recorder picked from the garbage in series (later when I obtained an LCR meter they measured around 2H IIRC). It worked but sounded too harsh so I crudely slapped some C (around 3n?) across the output (I think it should've been some series R then C) and that helped to tame the highs and it was pleasing but simple series R seems a lot easier if it does the job.

(check out these comments from Dave Weyer, who apparently modded some of Jimi's wahs, fuzzes, and amps) :

https://forum.metropoulos.net/viewtopic.php?t=44339
https://forum.metropoulos.net/viewtopic.php?t=43932&start=1575
https://forum.metropoulos.net/viewtopic.php?t=32828&start=150
https://forum.metropoulos.net/viewtopic.php?t=44159&start=150

This has interesting info on the Crybaby/Vox circuit (there is a clickable schematic with analysis and tweaking suggestions such as lowering the value of the 220nF connected to the output down to 47nF). Note that the page is in Japanese so (unless you happen to read such you'll need to use something like Google translate or deepl) :

https://alltubepreamp.blog.fc2.com/blog-entry-80.html

 

[Spencerleehorton]

Yes the range of the wah doesn’t work at the moment with this first buffer I’ve build into the wah and the wah first and FF second.
I will try the 50k pot on the FF input and see how that goes, along with keeping fuzz low.

 

[dai h.]

here's a Fulltone '69 schematic (appears to be originally from General Guitar Gadgets) :

https://blog-imgs-27-origin.fc2.com/c/a/s/castman/FLUU69.jpg

also, here's a thread where Gus explains the input stage interaction:

http://www.diystompboxes.com/smfforum/index.php?topic=60161.0

 

[Spencerleehorton]

here's a Fulltone '69 schematic (appears to be originally from General Guitar Gadgets) :

https://blog-imgs-27-origin.fc2.com/c/a/s/castman/FLUU69.jpg

Doesn’t open up? But I’ve found this



Same thing?

 

[Spencerleehorton]

Sorry this is what I’ll try with the FF to see if I get the sweep back with the wah first in line.
I also need to come up with a list of wah testing procedures and mods.
So far this seems to be what I’ve got in mind.
1. Set DPDT switch lower so I can get more range in the wah sweep, cut off rubber stoppers.
2. Select the right resistor, inductor and capacitor arrangement for widest vocal range for wah.
3. Test with FF so when first inline range of wah is working as expected.

 

[abbey road d enfer]

Yes the range of the wah doesn’t work at the moment with this first buffer I’ve build into the wah and the wah first and FF second.

You didn't say what buffer you used...schemo?

 

[dai h.]

re: schemo, yes the same (opens up for me so I have no idea what's going on there)

re: 1. the recommendation for cutting off some of the height of the rubber bumpers (and use a thinner felt bumper thing under the treadle which the top of the footswitch hits)(IIRC) I first saw on my Roger Mayer 9090A (wah) kit. I personally liked to set it so it wasn't too easy (required a little bit of force) for the switch to be actuated (so I couldn't accidentally turn the wah off when the wah effect is on). This was very fiddly and one problem was the switch would get sort of 'stuck' if the adjustment wasn't just so (but worth it to avoid hassle).

re: 2. IIRC the gain of the first transistor also had some effect on the range of the effect. Also reading Dave Weyer's posts it sounded like tweaking the 10nF (in the feedback) helped to optimize things (just guessing but maybe partly from the inconsistency of the inductor value(?)--I don't think they were very consistent--for example I have 3 or 4 relatively recent black Dunlop wah inductors, and (while I forget what they measured) they weren't very consistent).

Years ago I didn't have much idea of what I was doing and did some crude experimentation putting in variable pots and sockets (plus a rotary switch to change the aforementioned 10nF value), and (IIRC) my results seemed to agree with R.G. Keen's Technology of the Wah article (much more sophisticated than my hacking of course). And later on, looking at the Teese RMC3, that was pretty similar with a number of trim pots and a DIP switch with switchable Cs (plus two C trimmers) for that 10nF. For me I found smaller increments in the nanofarads were more useful for tweaking than bigger 10nF range jumps. The RM 9090A kit inductor measured a bit low and was kind of thin sounding as well. I also have an old Thomas with the TDK inductor (with the original pot) and there is something a bit different sounding compared to my other ones (Dunlop, Teese, guinea pig wah) but I'm not sure what exactly it is.

 

[Spencerleehorton]

You didn't say what buffer you used...schemo?

this is the buffer ive used so far but ive put in a J201 fet as didnt have any 2n5458

https://fuzzcentral.ssguitar.com/axiswah.php

also ive put in 2n5089 transistors, i have some 2n2222 which are apprently good?

my inductors both measure in the 530mH
one wah now sounds really good with an extra 12nf on the 10nf, i'll detail the other changes.

 

[abbey road d enfer]

Well I’ve put in the output buffer and put guitar into wah wah then fuzz and then wah doesn’t work, the other way fuzz then wah second wah works fine?

Can you tell exactly hat doesn't work?

I was under impression that an output buffer sorts out the wah in position one?

A buffer at the output reduces the interaction between the wah and what follows.

 

[Spencerleehorton]

Can you tell exactly hat doesn't work?

A buffer at the output reduces the interaction between the wah and what follows.

The wah range does not work when the wah is first in line and fuzz second.
Wah second and fuzz first works fine.

 

[Gus]

You might want to check out diystompboxes.
Wha adjustments were covered years ago you might want to search that site

 

[dai h.]

Dave Weyer did a video showing the Jimi wah some time back (if memory serves it was up for auction) :

 

[CJ]

Morley Fuzz Wah might be worth checking out,

 

[dai h.]

this is the buffer ive used so far but ive put in a J201 fet as didnt have any 2n5458

https://fuzzcentral.ssguitar.com/axiswah.php

also ive put in 2n5089 transistors, i have some 2n2222 which are apprently good?

my inductors both measure in the 530mH
one wah now sounds really good with an extra 12nf on the 10nf, i'll detail the other changes.

(not sure so I'm asking) do you require more filtering and de-coupling when putting in the buffer? My Dunlop GCB-95 and Roger Mayer 9090A kit (but not the vintage circuit Vox V847) have something like 1k5 and 100uF(IIRC--at one time I tried 100uF or thereabouts without the R and the wah didn't seem to work as well for some reason--do you need to simulate the impedance of the 9V battery(?)). This (apparent copy of Foxrox wah output buffer) shows 10R and 10uF (to the op amp power supply) :

https://www.freestompboxes.org/viewtopic.php?t=25452

 

[Spencerleehorton]

well so far everything ive tried doesnt sound as good as when the wah is in second position, wah first, fuzz second with 50k trim pot on input of fuzz, kills the fuzz a fair bit and yes it works to a point but the wah just doesnt sound as good as the other way?

 

[Spencerleehorton]

I think the next thing to try is the fox Rox buffer.
I’ve made an axis fuzz and I think I prefer it to the fuzz face but it does oscillate when fuzz is up full? I just have to back it off a bit until oscillating is gone!!
Only differences I used a 5k pot with a 3.3k resistor in parallel to give 2k and I used a 6.8uf for the 2.2uf cap.
Maybe that’s why it’s oscillating?

 

[dai h.]

well so far everything ive tried doesnt sound as good as when the wah is in second position, wah first, fuzz second with 50k trim pot on input of fuzz, kills the fuzz a fair bit and yes it works to a point but the wah just doesnt sound as good as the other way?

in what specific way? (Maybe if you can describe with a bit more detail that will give somone with more technical nous (than myself) a clue?--sorry I can't be of more help here!)

re: the squealing: I've built a silicon transistor version and experienced the same. The Dunlop (silicon transistor) reissue has (some unknown) value (assumedly small) value cap across the feedback R and a 10R in series with the 22uF (which I assumed was meant to deal with that--not totally sure).

https://www.freestompboxes.org/viewtopic.php?f=1&t=1727&p=194788&#p194788

Also, a reverse audio taper pot for the Fuzz control apparently gives finer control (never got around to trying it).

(another thing from the Japanese page mentioned previously) the author points out copious use by Jimi of (relatively high C) coily cords, so more C load for the wah output and fuzz output. Also the old Vox/Crybabys aren't true-bypassed and IIRC Univibe (if in the chain) is not very high input impedance.

https://alltubepreamp.blog.fc2.com/blog-entry-75.html
https://alltubepreamp.blog.fc2.com/blog-entry-76.html

(gratuitous Hendrix gear related video) :

 

[Spencerleehorton]

Well so far I’ve opted for 22nf instead of the stock 10nf on the first 10nf cap and the other I leave at 10nf in the wah.
My best distortion which I always use is the ZZtop expandora which sounds closer to a fuzz than a tube screamer and has lots of options sounds great with the wah as well.