How does the Hendrix wah compare to the mod-able wah at GGG

[kevn]

Hey Paul, Thanks for the response. Personally I'd like to think that the inductor doesnt matter that much because then I wouldnt care when I hear that there values are all over the place. So your understanding is that I shouldnt be able to tell the difference between 100 mf and 500 mf in this circuit. I cant find the original post where the variation was mentioned, but I do remember the person who wrote it was also of the opinion that 500 mf was about right for a wah inductor, kinda implying an opinion that it mattered. Opinions also seem to be all over the place...... For me, I'd like to simply try 2 different inductors with a wide seperation and see for myself. For that I'd need to get a meter that measures inductance, which I'm guessing is not a trivial investment that I'd probably use 2 or 3 times.

[lacto]

Thank you Paul for putting up that link to the wah patent. That is very interesting, and certainly clarifies that the most
critical relationship is that between the sweep cap and the inductor, at least in the minds of the inventors. If the inventors
are still alive, I bet their minds are boggled at the debates raging over their creation some 35 years later. 

[Paul Marossy]

Hey Paul, Thanks for the response. Personally I'd like to think that the inductor doesnt matter that much because then I wouldnt care when I hear that there values are all over the place. So your understanding is that I shouldnt be able to tell the difference between 100 mf and 500 mf in this circuit. I cant find the original post where the variation was mentioned, but I do remember the person who wrote it was also of the opinion that 500 mf was about right for a wah inductor, kinda implying an opinion that it mattered. Opinions also seem to be all over the place...... For me, I'd like to simply try 2 different inductors with a wide seperation and see for myself. For that I'd need to get a meter that measures inductance, which I'm guessing is not a trivial investment that I'd probably use 2 or 3 times.

I didn't say that it doesn't matter, what I said is that it doesn't matter as much as people think. People seem to think that if they change the inductor out, it will magically make their wah pedal sound like Jimi or whoever. The value does matter because it will shift things around some, but like RG says in the "Technology of Wah Pedals", as long as it's between 400-600mH, it'll be fine. The fine tuning with caps is what has to be done. An inductor with a 100mH inductor is not going to sound good - too small of a value for use with guitar. None of this changes the fact the the singlemost biggest part of the inductor based wah circuit is the feedback cap and its interaction with current (reactance).

Thank you Paul for putting up that link to the wah patent. That is very interesting, and certainly clarifies that the most
critical relationship is that between the sweep cap and the inductor, at least in the minds of the inventors. If the inventors
are still alive, I bet their minds are boggled at the debates raging over their creation some 35 years later.

Thank Jack Orman! I did obtain a copy of the patent thru another source back in July and I have been studying the part that explains the operation of the circuit since then. Very fascinating. Long live the wah! 

Based on what I have read in the patent documentation, IMO, the only thing that the inductor is there for is to make it a resonant circuit (although it adds some complimentary reactance). The actual value of the inductor matters only for the resonant frequency range. Anything between 400-600mH will work fine. 500mH seems to be the preferred value by most. Anyhow, back in the late 60s to the mid 70s, components were pretty variable. It's just like the old Fuzz Faces - you could get a jewel, a dud or something in between. So trying to recreate Jimi's wah, for example, is a very elusive thing to do!

[LoudGreg]

"So trying to recreate Jimi's wah, for example, is a very elusive thing to do!"

I totally agree. It would be nice to have Jimi's wah sound in a box but that just not possible.

I have modded my wah to have three inductors, Fulltone, TDK, & Fasel Yellow. I can hear the difference and it's kind of fun to be able to change the inductor on the fly. But it's so subtle that I would not expect even my band mates to notice what I was doing. 

I just need to put in a rotary cap knob now  and then I'm all set !!!

The Wonder Wah (Wonder which setting to use today)

[Paul Marossy]

I have modded my wah to have three inductors, Fulltone, TDK, & Fasel Yellow. I can hear the difference and it's kind of fun to be able to change the inductor on the fly. But it's so subtle that I would not expect even my band mates to notice what I was doing.

I rest my case!  :icon_lol: 

I just need to put in a rotary cap knob now   and then I'm all set !!!

That's the most noticeable change that you can make - switching between various sweep cap values. 

EDIT: Something else that might be interesting to experiment with would be to replace the 1.5K resistor on the emitter of Q1 with a 2K pot and see what affect it would have. According to the patent documentation, the 1.5K resistor is there "to admit some of the non-favored (off-peak) frequencies into the amplifier, so that they could pass to the output". Without this resistor, "virtually the only frequency appearing at the base of (Q1) would be the selected frequency, because of the high Q of the circuit". The presence of that 1.5K resistor "allows all frequencies to be developed to a certain extent thereacross, and hence to be passed to the amplifier".

Hmm... it sounds like messing with this resistor could further shape the sound. 

[formerMember1]

didn't wah baby's have a 250mh inductor, ala jimi page etc,..or i could be wrong,...

THat 1.5k is tricky, put it at 2.2 it is too much, at 2k it is too much, i was thinking 1.8k would be nice, but don't have the resistor,...I found out from testing that i like the wah built stock values, To me, the red fasel i have(don't know it's exact mh and ohms), but i hated it compared to my ArielFx Halo, i first had the halo in thier, and didn't like the wah much, i thought it was the halo, so then  i unsoldered the red fasel from my crybaby classic, and put it in my clyde clone, and then i really heard how bad a wah could sound, it was muddy, and dark, not much vocal to it, the halo had nice treble, clear tone, more vocal,...just my experience,...

Only thing i can't make my mind up on is the 100k Q resistor, i keep changing it from 47k to 51k to 82k to 100k, most of the time i go back to the 100k, but sometimes it seems to much if used with a fuzzface, but clean the 100k sounds best,...pretty soon i am just gonna solder the 100k in thier and forget about it,...

so audioguy(i think you made this thread), make sure you get, a 33k 47k 51k 62k 82k and 100k to try in the Q/vocal parallel to inductor Resistor,
Also get a 1.5k, 1.8k 2.0k 2.2k for the mids mod, also get a 470ohm, 430ohm, 390ohm 330ohm, to try for the bass resistor, also try adding a .001 or .002 cap in parallel to the .01uf sweep cap, to adjust sweep, someone told me to try a .02 cap for sweep cap, but i thought that was WAY too much,...but opinions vary. 

I don't know if thier is a difference in tone as far as a Fulltone Halo and a Areil Fx halo, if they are both 500mh and 30ohms,...

i like the propot, others like the fulltone pot, others again like the dunlop pot, to me they go,..

dunlop has quickest/shortest sweep, better for high gain amp playing,...

fulltone pot, is also a quick sweep like dunlop, but it has a little bit more sweep to it, is more vocal, and sounds more like Brave Ulysees by Cream

PROPOT, is the longest sweep, less vocal then fulltone, but a 100k vocal compensates for this, and the propot sounds more like an original clyde

hope i helped some,...

~~EDIT~~
Fretwire gave me good advice,,... when changing the pot or inductor, one must tweak the mids, bass, Q ,resistors(and possibly sweep cap), to adjust tio that pot or inductor,  for best results,...

again, use your own ears and what you like, don't just use a 100k vocal resistor becuase i like it, or hendrix used it, use your ears and decide if 100k is too much, or perfect,...maybe a 82k will sound better with your amp, when a 100k sounds the same as your setup on my amp/guitar,...

i also noticed my wah sounds way more vocal and midrangey and thicker on my humbucker guitar, vs my single coiled hendrix strat,..

[joelap]

Hey, first post here... hope these are friendly waters!

I recently had some mods performed to my wah pedal, from which I tweaked it some more.  It's a Vox 847 wah that had the following changes done to it by either me or a modder from Florida.  It's got true bypass DPDT switching, the Q resistor and the midrange resistor both have trimpots installed (modder did that, I'm at university now so I dont have the values on hand).  The input resistor was lowered I believe by one resistor value to give it a little more of a volume boost.  A knob was added to the side of the wah to vary between a stock v847 resistor and a "Real McCoy" setting... it's labeled as a gain knob but it sounds like it makes the wah a bit more "honky" to me.  It's got a Fulltone pot also.  On the topic of the inductors, I ordered a Banzai Halo inductor and got the chance to install it on thanksgiving.  It was replacing a yellow Fasel inductor.  I havent had the chance to plug it into my Sound City 50+ and crank it yet, but on a home practice amp I can say that there honeslty was not much of a difference.  Noticable, but nothing night and day...

I planned on putting a rotary switch on the side of the pot to switch between different sweep cap values ... right now it's got a .012uf cap I believe, but I'm not really a setting-tweaker.  Once I find a setting I like, I usually leave my pedals set at it and rarely change it, yet somehow I never forget the settings either, so I doubt I'd use it much.  I'm planning on puttng the stock input resistor back in and putting an even lower resistor than what was modded on a switch to be able to switch between an even volume and a boost for soloing.  I'm going to have to try to tweak the cap that controls the current going into the inductor, see how that sounds... but first I need to get through final exams!

Joe

[Paul Marossy]

didn't wah baby's have a 250mh inductor, ala jimi page etc,..or i could be wrong

I dunno. I do know that the grey Vox wahs (like Jimmy Page used) had a 250-300mH inductor.

THat 1.5k is tricky, put it at 2.2 it is too much, at 2k it is too much, i was thinking 1.8k would be nice, but don't have the resistor,...I found out from testing that i like the wah built stock values

You always use a trimpot to get it dialed in exactly where you want it...

Only thing i can't make my mind up on is the 100k Q resistor, i keep changing it from 47k to 51k to 82k to 100k, most of the time i go back to the 100k, but sometimes it seems to much if used with a fuzzface, but clean the 100k sounds best,...pretty soon i am just gonna solder the 100k in thier and forget about it

Trimpot to the rescue! 

i like the propot, others like the fulltone pot, others again like the dunlop pot, to me they go,..

dunlop has quickest/shortest sweep, better for high gain amp playing

I like the ProPot in my 70s Italian made Vox wah and the Dunlop Hot Potz II in my Maestro Boomerang clone (and CryBaby's). 

[Dai H.]

to my ear (w/Burning of the Midnight Lamp as reference), 100k for the 33k sounds more correct (smaller seems more "swishy", bigger = wider sounding), as well as going lower for the 470ohms (around 470ohms sounds like the Vox demo record--more goofy sortof--lowering it boosts and fattens the sound). The200k Propot sounds good to me over the other ones I've tried (Bourns, Dunlop, Fulltone). For the 1.5k (I have a pot in there), I think I went a bit lower(?).  Listening to "Up From the Skies" I wonder if that had a different tuning or something? A lot (when it comes to wah sounds) is probably a matter of taste. fwiw I tried a 0.1uF polystyrene (the biggest value polystyrene I could find up to that point) for one of the 0.22uFs (they were both 0.1uF in the RM9090A kit), and they seem more clear and true in the high end (compared to same value boxed metal poly). Might get some tropical fish just for the hell of it.

[formerMember1]

i was gonna use trimpots, but i thought it was better to just use a resistor, for some reason,...

it's labeled as a gain knob but it sounds like it makes the wah a bit more "honky" to me

I would like to know what this is, cuz i would like to hear my wah more honky for a change,... i guess it was a mids resistor change,..1k5,....

i never heard up from the skies,..does that have a lot of wah in it,...

[Dai H.]

we're talking Jimi Hendrix wah and this guy hasn't heard Up From the Skies... lol 

You definitely got to listen to that one! Also, it seems useful to listen to his concerts (or footage), bootlegs where he uses wah without the studio processing (plate reverb plus whatever else is on there).

[joelap]

I would like to know what this is, cuz i would like to hear my wah more honky for a change,... i guess it was a mids resistor change,..1k5,....

i never heard up from the skies,..does that have a lot of wah in it,...

The resistor that was changed comes stock on a Vox 847 as either 510 ohm or 470 ohm.  The Real McCoy's value is 270ohm.  It's supposed to give the pedal more gain and bass, but I dont hear that...  my pedal's knob varies from 510 ohms to 270ohms.  FWIW it was labeled as R8 on my Vox Wah... I found that the schematics on the "technology of a wah pedal" and one more website have the resistors and caps numbered differently than on my Vox 847, so I wrote down the values of the components as they were labeled on my wah, in case I was ever modding another for someone or a friend.

Joe

[formerMember1]

so the original wahs had 270ohms, that is really low, there must be alot more gain with that resistor, i liked it at 330ohm instead of 470ohm, for added bass at heel down, but i didn't like the fact that it took away the nice treble at the toe, it made the treble at the toe too bassy,  It definitely adds bass and gain, cuz i experimented with that resistor, but i never tried a 270ohm resistor, i wonder if this is how Hendrix got that nice low end on the back of the sweep, plus removing the rubber stoppers,  Roger Mayer might have changed that part,..Where did you hear/see that it was a 270ohms on Clydes?
I'll have to experminet with that resistor at 270ohm,...IIRC, i just realized that i tried that at 300ohms, and it was too bassy, but that was before i removed the rubber stoppers,..

I heard that song up from the skies many many times, i went through my hendrix stuff, i just forgot the name of it, when you mentioned it, i was thinking of that last part of the song where it fades and their is that nice wah tone, and was trying to remember what song that was, fair enough, it was that song  you speak of, that is what my wah sounds like, it is just that his is more quacky, and more of something i can't quite  pin point,...

[joelap]

Where did you hear/see that it was a 270ohms on Clydes?

The person who performed the mods on my pedal goes by the name Stratdeluxer97 on the Seymour Duncan forums.  He's a pretty reliable source, and he has gotten one-on-one experience with that wah I'm assuming.  Funny you should mention 330 ohms being your favorite spot... that is Stratdeluxer97's (John's) favorite spot, as well as another person who had the same mod done to his Vox 847.  330 seems to be the perfect blend.  I didnt know that Hendrix had the rubber stops taken off his wah... then again, I'm not really a Hendrix buff.  That sounds like something worth trying on my own wah maybe.  When I got this wah, the pedal was optimized for a strat... but I'm mainly a Guns n Roses / modern rock style player.  The sweep was perfect for a strat single coil with an SD-1 or tube screamer in front.  But for the less paul it didnt have enough sweep to it... I adjusted the pot and now the highs are perfect when toe down and still great for strat too... but it did lose some of the "bow" sound of the bass frequencies shifting... maybe removing the rubber stops temporarily as an experiment would fix that.

[formerMember1]

rubber stoppers removed you will hear metal hitting metal, zack wylde removed the rubber stoppers off his wahs, both front and back,...that is where i heard it first,...then i read somewhere where Jimi did it too,...I like it that way, i also removed the front rubber stoppers, but then the switch turns off very easily, i like it that way though,... for GnR, you might want to remove the back rubber stopper only, or saw off most of it, except for a little with a pocketknife, so that it still has some rubber so no noise, but has more sweep then full rubber, they are hard to remove, if not impossible with out damaging them,... I like the front rubbers removed and the switch set at a height, so that it turns off, but there is about a paper thickness before the pedal would hit the enclosure, testing is required for this,..i also remove the felt pad too, for even more sweep, but then you hear clank clank, but that doesn't bother me, another person i advised me to cut the felt in half, that works too, i used my soldering jig to hold the felt, then used the serated part of my pocket knife, to cut the felt in half, so that less thickness, then stuck hit back above the switch, the glue residue is enough to make it stick again,..   so i like to remove both front and back stoppers and also felt pad,...for more sweep, on my crybaby enclosure,...

here is a link of good info i guess,... 
http://www003.upp.so-net.ne.jp/kazuhee/ewahmod1R.htm

and also,...

http://www.realmccoycustom.com/ADJUSTMENTHELP.htm

hope that helps,..

[LoudGreg]

Quote
Only thing i can't make my mind up on is the 100k Q resistor, i keep changing it from 47k to 51k to 82k to 100k, most of the time i go back to the 100k, but sometimes it seems to much if used with a fuzzface, but clean the 100k sounds best,...pretty soon i am just gonna solder the 100k in thier and forget about it

Trimpot to the rescue!  "

What I did was wire the Q Resistor to a DPDT switch that has two trimmers. One set to my favorite 100K, and the other one is set close to half value (but this is the one I adjust to taste) I just keep switching back and forth when I want.

I'm going to do the same thing with the 1.5 (Mid)resistor as well. Right now I put a 2.2 in there and I like it but want to have the option of changing it with the flick of a switch if I don't want too much of a mid biting sound. I'll probably DPDT it with the 2.2 on one side and a trimmer on the other.

[joelap]

Ritchie, thats good stuff!  I'll think about removing the back rubber stoppers first... That might do the trick in itself.  The wah is very vocal as it is.  I'll see if I can adjust the pot maybe a touch more to the bass side before resorting to removing the rubber feet.  Thanks for the links, I'll check them out sometime when it's not 11PM and I've gotta wake up at 6AM to drive an hour through traffic to go to engineering classes 

Joe

[markphaser]

the fact the the singlemost biggest part of the inductor based wah circuit is the feedback cap and its interaction with current (reactance).


What Current Reactance? where at in the feedback path the current reactance? how do u change the current reactance in the feedback path?

What Components or Values change the current Reactance in a Wah?

[Dai H.]

tried a 120k for the 33k (the 120k was an old carbon comp and it actually was waay off at about 135k  ). Seems less trebly when I step down.

[Paul Marossy]

What Components or Values change the current Reactance in a Wah?

The "sweep capacitor" first and foremost. Then the inductor.