| Author |
Topic: Impedance question |
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 9 Nov 2018 10:56 pm |
|
I had occasion to play my old Stringmaster T-8 today, and hooked it up to my original Fender Vol./Tone pedal. When I put my Lil Izzy in the chain, the 'tone sweep' has NO effect.
Can anyone explain in lay terms why that is? I don't know the value of the pots,, but I'm assuming that has something to do with it? Just curious. Thanks! |
|
|
|
Georg Sørtun
From:
Mandal, Agder, Norway
|
Posted 10 Nov 2018 12:52 am
|
|
Trying to simplify the case…
You are right in that it is a question about impedances.
The passive Fender Vol/Tone pedal is designed to interact directly with a passive PU coil. The simple resistor (pot)/capacitor "tone" circuit loads the 6Kohm or higher PU impedance, to get the effect.
Connecting a buffer like the Li'l Izzy between PU and Vol/Tone pedal breaks this pretty complex, two-ways, RCL-RC ineraction. The V/T pedal doesn't "see" the PU, and the PU doesn't "see" the V/T pedal.
- The very low-impedance output on the Li'l Izzy literally overruns the high impedance resistor/capacitor "tone" circuit as if it wasn't there. The buffer doesn't react on the high resistance in the "tone" pot, and, if anything, it pushes the "tone" capacitor's frequency range up a few octaves – well into the inaudible range.
In practice there is nothing you can do to the Fender V/T pedal's passive circuit to make it work with a buffer between it and the PU.
The only place a Li'l Izzy (or other buffer) can go in your set-up if you want to get anything useful out of the "tone" effect of the Fender V/T pedal, is after the V/T pedal where it will counteract the effect of long cables. |
|
|
|
Dave Meis
From:
Olympic Peninsula, Washington, USA
|
Posted 10 Nov 2018 1:18 am
|
|
Thanks Georg! I appreciate your time. I never tried the Izzy after the pedal, and for years just used the tone knob for the 'sweep'. The original tone pot on my T8 is getting tired, so thought I might just use the pedal instead, and was surprised when it didn't work. Guess I'll lose the Izzy ..  |
|
|
|
