Vox 847 wah sweeping curves and shape mods

[markphaser]

I have a Vox 847 wah wah its new but im curious to see if there is some sweeping mods i can do to this

Moving the pedal back and forth is linear is there a way to get different sweep curves and sweep shapes?
how would i do this?

The feedback cap. just changes the vocal range but im looking for more of changing the sweep curve and sweep shape

Sweep curves can be linear,log,exp. etc just a different sweep curves

[Stevo]

I know a good Halo inductor will make a real nice tonal change.....
Ariel.com    sells them...

[markphaser]

yea but the sweep curve and sweep shape is going to be the same tho it would just be a tonal/timbre change different Q resonance

[markphaser]

The feedback cap is Positve or Negative feedback path?
Because its branching off the emitter of the transistor

Does the Feeback cap flip the phase of the signal?

 

[Paul Marossy]

The sweep frequency range is determined by the size of the sweep cap. The sweep curve would be determined by the taper of the pot. The feedback cap does not invert the signal, AFAIK. Since the sweep cap is connected to the emitter of Q2, I would call it a negative feedback. The input signal is inverted at Q1, per the patent documentation.

Read the patent, it's got a lot of informattion in it regarding the operation of the circuit.

[markphaser]

thanks for the information

The orgianal wah pots were Carbon Comp Pots, used 470K, 500K or 1M pots
With different resistance values for the wah pot wouldn't that give a different taper?

The old wah pots were semi-logarithmic taper i wonder what that looked like on a X axis and Y axix graph

How would i get a radical "S" taper?

Most pots are 270 degrees of shaft rotation
so the graph would be resistance VS degrees of shaft rotation

If the resistance is 100K and the shaft degrees is 310 what is the Taper?
If the resistance is 100K and the shaft degrees is 270 what is the Taper?   




HotPot, Rock Potz these are standard taper
Allen/bradley,The Teese pots with a special taper,The Fulltone pot  a modified taper

The taper of a pot refers to the way its resistance changes as the shaft is rotated. A linear taper pot is exactly what you would guess it to be, a graph of resistance (from one end to center) versus shaft rotation would be a straight line

The rate at which the resistance of a potentiometer or fader changes as it is raised or lowered. This can be visually represented on a graph with resistance represented on the Y-axis and pot rotation represented on the X-axis. Some of the names of the tapers relate to how this relationship draws out on the graph. For example, Linear taper is a straight line (linear) at 45 degrees up across graph

[Paul Marossy]

You're probably not going to find graphs on any of these old (or new) wah pots. Have you read "The Secret Life of Pots" at www.geofex.com? That might be of some help...

[markphaser]

What is taper? It's just the ratio of the resistance already passed as the pot turns to the total resistance of the pot, described as a curve

Taper is Percentage or ratio of Rotations VS percentage or ratio of resistance

tapering resistors is to connect a "tapering resistor" across the wiper and CCW lug,

What are some tapering resistors with other tapering components across the wah pot can make different curves or sweeps?

I heard George Harrison wah wah pot has a "tapering inductor" across the wiper and CCW lug to give a different sweep
what would this do?

[markphaser]

Moves the resonant frequency peak back and forth across the frequency spectrum or frequencys scale

The feedback cap changes the Feedback impedance?

Capacitive reactance is coupled with a Complementary reactance which is a inductor

A Wha has One center frequency? has one resonant frequency peak?

When moving the wah pot which changes the frequency of the resonant filter. The wha pot changes the frequency but the inductor/coupled capacitor has a Fixed frequency

The inductor/coupled capacitor sets a fixed frequency?

The wah pot sweeps the frequency spectum back and forth while the inductor/coupled capacitor sets the fixed peak frequency?

[markphaser]

Whats the difference between a 100mh inductor VS a 300mH VS a 500mH VS a 800mH?

Is it the Q factor? Center frequency? Cutoff frequency? Peak Q ? resonance?

[GFR]

Whats the difference between a 100mh inductor VS a 300mH VS a 500mH VS a 800mH?

respectively, less 200mH, 400mH and 700mH.   

[Phorhas]

I know a good Halo inductor will make a real nice tonal change.....
Ariel.com    sells them...

It's arielfx.com

http://arielfx.com/see_product.asp?idd=156

I got one installed in my 535Q and boy does it sing... it really shines now, even compared to my 1967 Vox wah

[Manolo Dudes]

It's arielfx.com

http://arielfx.com/see_product.asp?idd=156

I got one installed in my 535Q and boy does it sing... it really shines now, even compared to my 1967 Vox wah

Ditto! 

[markphaser]

That site is in spanish i can't read it but nice pictures