# Finally got the wah out...



## PaulS (Feb 27, 2006)

A while ago I had posted my vox 847 up for sale. There was some interest but no cash showed up... The vox had been modified in large way, I have been expiermenting with it for the last two years. It sounded good but not what I really wanted. The pedals has been true bypassed, Fulltone Halo inductor and Fulltone Icar Pot. I had changed out all the caps for a higher grade and changed all the resistors to the brown carbon comp type and changed a few values. Here is a pic of the board..








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Well since it was sitting on the shelf I thought I'd give it another look. I googled the 847 for mods and found one by a gent who had went through all the trouble converting his back to the specs of the Italian 846. I read his thread and thought what's to lose.. Anyway Changed out a C1 and C5 with mallory .01 uF caps, left the .22 uF orange drops . C1 is the input cap and C5 is the sweep cap and the type of cap used here does change the character of the pedal. Next I replaced all the resistors with 1% Metal film resistors with the exception of the input resistor because I had changed the value and didn't have the right metal film value. Basically most of the values stayed the same with the resistor across the inductor changing to 27K and the input resistor to 47K. The last change was the transistors, in his article he suggested that the 2N5172 type were far better than the MPSA18 type that were used in the 847's. To try this I hooke up a couple temp sockets and A/B'ed the two pairs. The 2N5172's were actually a lot nicer than the original so I soldered them in permanently. That was a trick because the pin out differs between the two. Finally I have the wah that was hiding inside that pedal. A very expressive sweep sort of vocalish and just the right range. That is another trick, finding the sweet spot on the pot.... many moves of the pot until it was finally there.... now some pics....







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## SnowBlind (Feb 26, 2006)

Wow very nice Damn if only i could do a decent soldering job i might try that. How about you start a v847 transformation business. Ill be your first customer


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## PaulS (Feb 27, 2006)

possibly... don't know about the availabilty of the halo inductors or Icar pots but he did have a setup for the red fasel inductor and you could use the Dunlop hot potz, they are not that bad, I have one in my home made wah.


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## elcabong (Mar 6, 2006)

Hi Paul,

of the changes you made, would you say that the change to 2N5172 had the biggest impact?

I recently gutted out a Vox 847 and put in a board from General Guitar Gadget. I am using an Halo inductor from ArielFx and a yellow Fasel; this board allow you to use one or the other ( you know that already ). I personally prefer the Halo inductor.

I went with the MPSA18 but I will give the trannies you mentionned a try.

Gilles


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## PaulS (Feb 27, 2006)

I have another wah with the GGG board in it and I used a red and a yellow fasel. I to think the halo inductor has a better "wah " to it . The 5172's did make a change and it has become my preference. In the GGG board I'm using 3904's I think and I might try changing them also. If you try the 5172's beware the reverse polarity, you have to manipulate the tranny in there and I used insulators on the transistor legs.


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