How to Mod a Vox V847A Wah Wah for True Bypass and LED 

bthanks Paul i watched this video 15 months ago. a week later i decided to build a guitar pedal. now i have made 96 pedals .

Oh man, I had never done anything like this before, but when I saw your video I thought "hey, I think I`ll try to do this". Your tutorial was perfect and I was able to fix my pedal, since when it was shut off I could barely hear anything. Now both on and off sounds are prefect! Thanks for the video!

Awesome video. I did this mod step-by-step today and it worked perfectly.

Great!The video perfectly works.I modded my VOX 845 with True Bypass and 4 blue LEDs under the pedal.Looks extremly cool when wawing!

Thank you for this excellent step by step video. It saved me from buying the Vox V846hm which are way to expensive.

Thank you for your mod tutorial, easy to follow. I did it on my Vox V845, adding also a second power on indicator led. Very good job

Just found this video the other day. Was looking for some clear a d easy to follow instructions to do the true bypass and LED mod to my olde VOX 845 wah. This one id possibly the best I found even though its 7 years old now. So cheers mate thanks for info.

Yes, I did it and it was very easy but you have to know how, haha! Thanks once again and here's a happy man in Groningen

Awesome video, i just made the mod with the LED and to my surprise it did go well on the first try ! Thanks a lot !

Good job Paul. I've made the same on my chinese V847-a and it worked fine. Thank you for share this tutorial.

Thanks from Brasil Paul! Works perfectly!

Thanks for the excellent how to video Paul. I had a spare 3PDT switch left over from making a kit and quickly converted my old Vox wah to true bypass thanks to your video, I can really notice the difference.

Thanks for doing these videos Paul!

Followed to the letter (with exception to the LED - not required) and works perfectly on my £15 bargain. Thanks Paul 👍

I've been debating which pedal to buy. This video convinced me the Vox is likely the best way to go.

Great video. Just finished modding my old second hand v847 for true bypass, a super bright blue led, and a new 125k mojo pot. The difference in sound with the new pot was amazing and completely worth it to smooth the sweep and eliminate crackle, even if I had to literally saw the old pot off the small board to replace it.

Thank you for this!! Every step was very clear and I was able to tbp my wah ;)

Thanks for this Video. Works great with V845 too !

did it to Vox 845. works great THANKS!. my switch was a little short so i put a good blob of hot glue on the felt patch, it gave just enough throw for proper turn off on.

Thanks for sharing your knowledge. With your instructions I was able to modify my 845 and it works perfect. Best wishes from Germany!

thanks for the video i did in my 847 and work very well. Abrazo desde Argentina!!!!

Thanks Paul! I just followed your steps to refurbish an old VOX 845 that had a broken switch & a scratchy pot : It's now working fine with true bypass, LED indicator & no pot scratching! Couldn't have done it without your excellent tutorial. Cheers and here's to the good old wah-kah-chah-kah DIY

Thank you Graham. Great and very informative video. I just mod my son's 845 and works like a charm.

Thank you. Did it! Works perfectly!

Excellent instruction thank you am going to crack on and sort mine out now. Respect

Worked like a charm! Thank you!!

BigBigThanks, you saved my Pedal and Pedalboard from incompetence ;) i tried it myself but i didnt shortened the ground, so i had all the time the "noise while switching" thanks a lot. Nice content. Tip for next time: set focus on your camera to manual, was sometimes blurry the picture.

Thanks for the video! If you get a pop with bypass switches, it is due to the different dc voltage either side of the coupling caps. The best solution is to use an earth reference resistor on both caps. Something around 100k on the output cap and something around 1M on the input cap. Cheers!

Thanks Paul ! Great video!

Thanks for this video man! I learned a lot. You seem to have exotic wildlife in the backround!

Thanks i followed and works perfect

Great Paul that you shared this video! Makes everything sounds so much better! I own a Teye guitar and on it's own it sounds so nice ... unfortunately with the so called true bypass it's already starts to mess up

Paul...you are the best!!! thanks :))))

Thanks for this awesome video! Really easy to follow and I got my Vox wah successfully set up for true bypass with a super bright LED. I do get a noticeable pop when switching the wah on with some gain though. Gonna try putting a 22uf cap to ground in the LED circuit and see if it makes a difference...

Amazing video, thanks!

Thanks a lot for your excellent video! Clear instructions, step by step. I just finished this mode and I am excited. I chose a 5mm blue led with its bezel and it looks great. Can't wait to try it. Looking forward for your next mode. You should continue uploading this kind of modes.

Great Tutorial!! thanks

Muchas gracias, muy útil, saludos desde Costa Rica

This tutorial is great! Absolutely recommended.

Great vid! Thanks.

Thanks for this great video! I was able to do the true bypass and added LED strips inside the base so it glows when on. I'm getting noise when it's engaged now, it may be something on the same circuit causing it, I haven''t been able to track it down yet.

Thank You so much, Very well

Thanks for this,~always favored the Vox wah sound for most purposes. Really a shame Vox and Dunlop can't manage the extra 25 cents per unit to include true bypass.Wonder how many thousands of units they would sell if they did?But then, I guess their main target markets are newbies who don't know the difference, and/or will get discouraged and sell it in a year or two, anyway. ( Might apply to a vast majority of the entire market , period, now I think about it).

Just done :-) thanks ! it works perfekt.

hello paul thank you very much for this tutorial, but I would like to have a precision, in what direction of polarity is placed the LED please (the "+" arrives from resitance 510ohms and the "-" towards 3pdt?) thank you in advance

Hi Paul, Just made this mod on my brand new, and first wah. I added an extra LED under the Rocker for a cool glow effect. First time ever done anything like this and although it was fiddly and slow going IT ALL WORKED!!!! So stoked. Such a great video, perfect attention to detail and guidance. Not just cheaper than taking it to someone, SATISFACTION from doing it at home!

Can you also do a video on the bass sweep range mod for the V847a?

Paul, what steps would I want to disregard if I were to only install the true bypass switching without the LED?

Nice and helpful video! My question is: better the V845 or the V847A to modify? I mean, the 847 as more metal (looks nicer), the input buffer, the soft case and small surface electronic components, but as I will modify immediately, is it really better? The input buffer with the true bypass is still working or not? The price difference is really low (15 €), so it's not a matter of price, but just to understand which of them is better for the modification and if in case the 845 could be further modified for improve the tone or other characteristics. Thanks

Thanks, great instructions - I've converted my V845 and it works well and sounds good with true bypass - but, the LED is not lighting up when I engage the way was. Any ideas?

I'm getting some switch pop. Would anyone know where I could put the pulldown resistors specifically? I know its usually at he FX in but these surface mounted components are quite confusing. Thanks in advance.

Hi good vid , have you done any other mods to this model pedal ? it is quite different inside to earlier models

Hi Paul, thanks for the video. I followed point to point on my 847A and it works flawless. To anyone trying, I would recomend to look for the right 3PDT since the one I used (standar Musikding 3PDT footswitch) felt much softer to activate on/off than the original and sturdy VOX one (made in Mexico). So now it turns on/off almost with no pressure from the foot. Some might like it, some not.

Great Video, Bud! The Bypass mod worked well. Unfortunately I broke the resistor R4 during another mod. Is it possible to tell me the value of R4? Thanks in advance!

hi, thanks really usefull! a question please: do I must respect a particular orientation of the 3pdt footswitch?

Nice video man. Excuse me for my ignorance, but while i was searching for v847a wah mods i stumble upon someone that was concerned with removing the input buffer (the small circuit) in the back of the pcb - whats the deal with this thing ??? - should i remove it or not?

Is there any chance you have the full schematic for the V847-A? I can't find it anywhere online. I am particularly interested in the three tiny components mounted on the small PCB on the pot - L101, R101 and C101. I want to reverse the sweep of my wah and I won't be able to take that tiny PCB off the pot without frying those tiny parts. Thanks!

well done.

Great video with quality instructions.I have only a few questions please.I have a v847 and would like to do this mod.I saw where you soldered the wire for the led power underneath what looks like the 9v input for ac power on the circuit board.My wah doesnt have a power jack only 9 volt battery power.What/where would be the proper point of solder for this led power purpose please?And i see in the vid you used a 3 pull double throw switch but you said double pull double throw a few times.I dont know if you caught that by now.So my question is..i have a double pull double throw switch (6 pin) and would like to know if this mod can be done with that switch?Maybe double up the wires on the switch a few times?Thanks in advance!!

Cracking video with concise instructions. I wonder if this will solve the problem I have with a drop in volume when the effect is engaged, any help would be very grateful.

Hey, man! Cool video! I was looking for a video on this. I've made the true bypass mod on mine. Now I just need to add the LED. What happens if I install the LED without the resistor? Will the LED "burn"? Thanks!

someone could help indicate the scheme to install true by pass for cray baby 535

Has anyone traced the location of the input resistor on the Vox 845. I did the true bypass mod but would like to increase the overall volume of the engaged effect. The 68k input resistor on the old USA Vox 847 was easy to switch to a trimmer pot to achieve this but I can't for the life of me locate the input resistor on the V845. Anyone done this mod ?

And can you tell me why the green wire is broken off? Because of him, the tone is muted on the guitar?

Nice mod mate. Put a much lower resister in. Old fashioned pedal, old fashioned 'glow'.

Hi, anyone knows what does every coloured cable? i mean, signal in, signal out, fx in, fx out. Thanks

Paul: Your instructions worked great and I installed the bypass switch and LED to my Vox 487 pedal. I have set the switch height properly but when rocking the pedal, it makes contact with the switch and make a clicking sound when playing. Is this common with these types of switches? Is there anything that can be done to eliminate the clicking? Note: this is not a clicking sound to the amp. It is a mechanical clicking coming from the switch itself. Thanks.

good evening I need the electronic diagram of the wah wah pedal v847 thank you

I'm trying to find the correct resistor on eBay or Amazon. Can anyone tell me what watts? 1/4w ? I know to look for 510 ohm.

Why don't Vox do this?

is another mod for this wah ? chinese version ? (v847)

Hairdryer works well for heatshrink.... just don't tell your mates ;)

Hi Paul is a great video .. i did this mod step-by-step today and it worked the true bypass But the Led light is not work .. I tried everything reconnecting everything, reviewing the video several times but nothing .. I did not use a LED bulb used an LED ring but the function is the same, the strange thing is that if I test the LED just before connecting it to the pcb with a battery apart. but if I connect it in the contact of nothing works neither with battery nor with dc 9v ... I do not understand ...

What a LED need to this mod? Help pls

pls help.. sorry it wont get true bypass.. i followed each step.. pls.. help me back

Hey I cannot find a DPTT footswitch anywhere. Are you sure you don't mean a 3PDT switch?

Is this wah made in china or USA

Thanks for the tutorial. I modified my wah but i have a problem, I can't get the "seagull effect" to work, when I switch the input and output connectors and turn the 3dpt switch on, i only get the "silence effect" jajaja

pretty sure it's pronounced 'here' instead of 'heee'.