Hoffman Amplifiers Tube Amplifier Forum

Other Stuff => Effects => Topic started by: frank57 on April 22, 2012, 12:58:24 pm

Title: How to add dc jack to Vox Handwired 846 wah?
Post by: frank57 on April 22, 2012, 12:58:24 pm

I picked this up used on ebay and it's pretty good.
Superb construction.
Someone on a website drew up the board but I finished off the layout.
I'm pretty sure this layout can be used as a drop in replacement for older whas.

What's the best way to add a dc power jack to it?
Am I on the right track?

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: sluckey on April 22, 2012, 01:36:25 pm

Here's the mod I made to my '70s Crybaby to run it from an AC adapter or pedal board...

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: frank57 on April 22, 2012, 03:30:10 pm

Would that be for a positive jack connection or a negative like on the boss pedals?
So a diode would be needed as well?
What voltage should the caps be?
What does the 220uf cap that is there now do?
On my old Jen wha all they did was I think , a pos jack with no filtering.

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: sluckey on April 22, 2012, 03:59:29 pm

Quote

Would that be for a positive jack connection or a negative like on the boss pedals?

I don't understand. There was no power jack on the original Crybabies. 9V internal battery only. Hence my mod. Batteries did not last long if you were not diligent about unplugging guitar during breaks.

Quote

So a diode would be needed as well?

The diode prevents damage to the circuit in case an idiot tries to connect the battery (or power supply backwards). You'll see it on later models.

Quote

What voltage should the caps be?

A little more than the highest voltage in the circuit. 16V was popular when I did this.

Quote

What does the 220uf cap that is there now do?

There is no 220uF cap on my '70s Thomas Crybaby.

Quote

On my old Jen wha all they did was I think , a pos jack with no filtering.

That's cheap.

"Jen wha"   That's really Jen wah isn't it?   :wink:

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: frank57 on April 22, 2012, 05:35:03 pm

The jen supercrybaby came with a dc jack.
It was positive tip with zero filtering.

On this new vox 846hw it's a true bypass pedal and they added a 220uf cap there you can see on the schematic along with a 10m resistor.
Maybe that could be used somehow for filtering?


The construction can be seen here:
http://www.voxamps.com/us/pedals/wahwah_v846/ (http://www.voxamps.com/us/pedals/wahwah_v846/)

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: sluckey on April 22, 2012, 05:51:28 pm

Sorry. I thought you could adapt my mod to your application.

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: frank57 on April 23, 2012, 01:38:17 pm

Well there is another problem:
The pot does not have solder holes on the solder tabs!
What were they thinking?
So how do I solder two wires on there?
Wrap them around some how?

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: frank57 on December 23, 2012, 09:44:04 am

I did it like this.Works perfectly.
Can't remember what diode I used.4001?
It's a real nice wah.Very vintage sounding
and superbly built.

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: smackoj on December 29, 2012, 04:21:47 am

i have a clean boost pedal i would like to add the dc jack to. where does a guy get those kinda jacks.....mouser or ? 
also, i have a nice 18vdc power supply in a small package that would work nice....is it just the values on the caps that i would look at to ensure i don't fry the bacon?

thx, smacko   :icon_biggrin:

Title: Re: How to add dc jack to Vox Handwired 846 wah?
Post by: sluckey on December 29, 2012, 06:23:50 am

Quote

where does a guy get those kinda jacks.....mouser or ? 

Radio Shack

Quote

is it just the values on the caps that i would look at to ensure i don't fry the bacon?

Usually, but can vary with the particular pedal. Best to consult a schematic.