Vox V847-A Whipple Inductor Mod

[JonM]

I have an old Vox 847-A pedal that I wanted to mod and had the True Bypass mod installed at a local shop last week. Yesterday I ordered the Whipple inductor (pictured), and wanted to install it in my wah pedal. I am confused as to where to install the inductor as I have read - http://stinkfoot.se/archives/561 - that there are 3 inductors built into this wah. If you follow this link - http://www.thegearpage.net/board/index.php?threads/vox-847-a.387523/ - users also mention 3 inductors. Below I have attached gut shots of the Vox V847-A. Is the little black box labeled VOX L1A where you would install the whipple?

http://i.ebayimg.com/images/a/(KGrHqF,!psFBdl(G!,rBQo+D,ur5w~~/s-l1600.jpg

Also have any of you successfully installed the resistors in the Vox V847-A?

My order is as follows:

"This listing is just the Whipple Wah and just the 100K ICAR taper Wah pot.
(plus the resistor mod set, 100K, 57K, 2K, and 330 ohm)

This is for folks that already have true bypass in their pedals, or already have a switch handy.

These are the same high quality parts found in my other listings.

The Whipple Wah Inductor, is the world's best sounding Wah inductor.
each one is meticulously made and tested by me to exacting specs.

Adding a Whipple Wah Inductor to any stock wah Pedal will provide for a smoother more expressive
wah playing experience. Rich with overtones, and a clear fundamental. It's like taking the wool off
your stock pedal.

The 100K ICAR Wah Pot, it built to my specs, and provides a wider and more controllable sweet spot
on your pedal, now you can get the full range of your wah pedal's sweep. It's a long life pot and will
sweeten the deal.

The combination of the Whipple Wah Inductor and 100K ICAR Wah Pot will provide hours of
musical enjoyment for the whole family."

Someone mentions in the other thread, "There is 1 inductor on the top of the board and which is labeled L1
There is 1 inducotor on the wah pot board labeled L101
There are 2 inductors on the bottom of the pcb labeled L2 & L3

The purpose was to get a sound like the vintage Clyde McCoy wah and thus the extra parts. The reason it was called the 847A and not a Clyde McCoy is because Dunlop owns the name and not Vox. Also, when Vox put out a Clyde is was made by Dunlop and thus the name was used there. I suppose it would be confusing to have two pedals with the same name.:eek:

The 847A is not to be confused with the V847 because the V847 board did not use smt and is a typical wah in parts count and values used. It also did not have an input buffer.

Looking at the stomp switch the 847A is not true bypass."

http://i32.tinypic.com/29p6yr7.jpg

http://i30.tinypic.com/r8yvep.jpg

http://i32.tinypic.com/9sq5w5.jpg

http://i31.tinypic.com/16bbiaf.jpg

http://i27.tinypic.com/nmfg4n.jpg

http://i31.tinypic.com/17seno.jpg

[thermionix]

Yes, the black box labeled Vox L1A is the inductor that you replace with the Whipple.  My advice would be to do the inductor swap first, and see what you think of the sound, and not worry about the resistors at first.

[JonM]

Hey thank you for the reply. Yes I intend to do this as I have read a lot of people changing the resistors from stock and actually liking the way it sounded before haha. I just hope the tech I know can install the Whipple into my Vox V847A successfully because a guy on a different forum said the pin spacing is different. However Dandy Job replied to my message yesterday and said that it can be done so that is relieving.

[JonM]

Just an update to my last post, I suppose I will just print out these instructions for my tech and hopefully this applies to the Vox V847A as well. This is from the Dandy Job website:

Step 1: Remove the old inductor:You will need to open the bottom of the wah, typically there are four rubber feet on the bottom of the wah with little screws. They can be taken off with a Phillips head screw driver or just your fingers. Once you have your wah open there are two options. Some pedals have the jacks attached to the board; some don't. If your pedal does not have the jacks attached (older crybabies, most older wahs, new boutique wahs) all you need to do is remove the screws that hold the board to the chassis. If your pedal does have the jacks attached to the board (newer crybabies) you will need to either take a pair of pliers or even better a socket wrench and remove the nuts on the jacks in order to pull the board out. You do not need to completely remove the board in order to work on it. You just need to be able to get to other side of the board where the solder attachments are. Now that you can see both sides of the board, find the solder joints that attached the old inductor (usually looks like can, although there are many variations). Heat up the joints with a solder iron and remove the old solder with a vacuum pump or de-solder braid. If you do a good job that sucker will just fall out. Sometime, especially if there are four joints, it is helpful to heat up one side (two pins at a time) and then the other side, and slowly work out the old inductor. Ok, you have got the old inductor out. Sip, the coffee, or tea.

Step 2: Installing the WHIPPLE.Get familiar with the WHIPPLE. Take a good look at it. And look at the bottom. You will see some pins and numbers. These numbers will help you to attach the correct pins. The numbers read 1, 8, then 4, 5. 1 and 8 are the hot pins, these are the ones that need to be attached to the circuit. 4 and 5 do not serve any electrical function. If you have a board that has holes in it to accommodate all the pins you can solder them as a mechanical attachment. In most cases 4 and 5 can simply be bend down and out of the way. There is also a pin that is part of the clamp that holds everything together. That pin can be bent out the way also. Now there are two options. The old inductor will have either two or four pins. If there were two pins, that is easy; attach 1 and 8 to the board just like the old inductor. If the old inductor had 4 pins it is a little more tricky. You will need to look at the traces on the board and determine the best way to orient the WHIPPLE so it completes the circuit. Another way to say this is, Pin 1 and 8 will bridge the gap between the traces, (it is a beautifully thing). In many cases the WHIPPLE's pin spacing will not match up with the old inductor's pins. Do not worry! There are two easy ways to fix this.

A. The Super easy way is to attach one of the pins to the board and then run a short jumper wire to the other pin. This is where a needle nose pliers come in handy.

B. If you want to get a bit more advanced you could run two jumper from the board and then bend the jumper wires so they match perfectly with the WHIPPLE, and then solder everything together.

[JonM]

I will be getting the Whipple installed this week, I really hope I can tell a difference. The main thing I am trying to do is remove the muddy bottom end and shrill top end. I hear some people switch out the "vocal mod" that is a 68k transistor, in addition to the inductor, to achieve this. However the included resistors are "This listing is just the Whipple Wah and just the 100K ICAR taper Wah pot. (plus the resistor mod set, 100K, 57K, 2K, and 330 ohm)"

So I am not sure which of the included resistors would be the "vocal mod", or where to install it in my wah pedal.

[thermionix]

The intent with the "mod" resistors is to swap the stock 33K resistor (in parallel with the inductor) with a 100K, as was used in the original mid-60s Vox Clyde McCoy wahs.  Some people like 68K instead of 100K, you could also use the 56K.  In my wah I have a 33K in series with a 50K pot (variable resistor).  There's a noticeable difference between min and max (33K and 83K), but it's fairly subtle.

What does it do?  It changes the "Q" or sharpness of the sweep, or the quickness of tonal transition as you rock the pedal back and forth.  It doesn't change the overall tone of the wah.  FWIW, by the late 60's, most wahs came with 33K, and have ever since.  So that's what you've heard the most on classic recordings and whatnot.

If your goal is to really nail a vintage wah tone, I would recommend removing the input buffer circuit.  With true bypass, it serves no real purpose.  That would do more than any of the mod resistors, IMO.  But as always, best to try one mod at a time, see what you think after the inductor swap, might be perfect to you.

[JonM]

Man thank you so much! I will have the tech remove the input buffer in addition to the Whipple installation and I will be done. If I want a different tone I will just buy a different wah. Now I just have to figure out how to remove the input buffer in the Vox V847A.