Effect of Input Impedance (1M + Cap)

K

kruzty

Inspired
I was messing with the Input Impedance parameter and when I switched between 1M and 1M + Cap, I seemed to like it with the added capacitor (at least for whatever preset I was using at the time). I was just curious as to what exactly the cap is doing to the signal, tone-wise? Is it similar to adding a treble bleed cap to the guitar's volume pot?
 
The comments are basically what the manual says - that there is a general pickup loading difference depending on the selected impedance. I'm looking for what, specifically, the added cap does to the tone. I can hear a difference, but I can't quite put my finger on it. Is is something as simple as "it increases/reduces high frequencies" or is it something more involved?
 
I'm not sure Jimi had a whole lotta choice. As I remember back in the '60s, guitar cords were some pitiful things. I'm sure he hooked up with whatever would carry signal and thanked his lucky stars it would do that much. It was usually a cheap, coiled cord not much different from the telephone handset cords of the time. Lotta capacitance, lotta resistance, and measurable inductance.

Of course, nobody even considered those things back then, so it's not like he (or his techs) went in search of something "appropriate" for the sound. It was just a happy side effect.
 
Adding capacity shifts the resonance frequency of the pu down.
Here's a quote from Bill Lawrence page to illustrate the effect:

High-capacitance cables shift the resonance towards the lower frequencies which dramatically alters tone. For example, Jimi Hendrix used a coiled cord with 3,000 picofarads (.003 microfarads), shifting the resonance below 2,000 Hertz on his Strats. This was the secret of Jimi's tone. Shifting the resonance frequency at 2,000 Hertz has a similar effect to a midrange boost. However, when he recorded and needed a typical Strat sound for some tracks, Jimi switched to a short, low-capacitance cable.
 
I suspect this is analysis after the fact. They just weren't that sophisticated back then. The more likely explanation for the cord lengths he used is that in the studio, he was only 5 feet away from his amp, while on stage he was all over the place and need 25 feet or so.

I'm not denying the effect - I'm sure that's a fact - just the motivation for what he did and why.
 
Hubertus said:
Adding capacity shifts the resonance frequency of the pu down.
Here's a quote from Bill Lawrence page to illustrate the effect:

High-capacitance cables shift the resonance towards the lower frequencies which dramatically alters tone. For example, Jimi Hendrix used a coiled cord with 3,000 picofarads (.003 microfarads), shifting the resonance below 2,000 Hertz on his Strats. This was the secret of Jimi's tone. Shifting the resonance frequency at 2,000 Hertz has a similar effect to a midrange boost. However, when he recorded and needed a typical Strat sound for some tracks, Jimi switched to a short, low-capacitance cable.
Click to expand...
I was just going to post this story, but you beat me to it.

I talked to Bill a couple of times on the phone a few years ago. It was mind blowing and embarrassing at the same time.
 
Is it anything like if you have long cable runs with pedal boards and use a buffer to get your tone back but the other way around
 
Hubertus said:
Adding capacity shifts the resonance frequency of the pu down.
Here's a quote from Bill Lawrence page to illustrate the effect:

High-capacitance cables shift the resonance towards the lower frequencies which dramatically alters tone. For example, Jimi Hendrix used a coiled cord with 3,000 picofarads (.003 microfarads), shifting the resonance below 2,000 Hertz on his Strats. This was the secret of Jimi's tone. Shifting the resonance frequency at 2,000 Hertz has a similar effect to a midrange boost. However, when he recorded and needed a typical Strat sound for some tracks, Jimi switched to a short, low-capacitance cable.
Click to expand...
this

Yes...Caeser Diaz, Stevie Ray Vaughan's guitar tech, is documented in ToneQuest interview saying the same thing about this issue, that the long coiled cords cut some top end of the Strat. He said that Stevie tried and hated the modern super Hi-Fi guitar cables, with a quote of something to the effect of "these pass too much electricity." Now I repeat this not to say it is gospel or anything like that, or that things were by design, I agree with post above saying this is was just the cable they had at the time for Jimi...

I never thought about changing the impedance for a Strat that is kinda shrill so that's nice to know we have yet another fine option courtesy of Cliff & Company.
 
I just started redoing my patches in vs 10 and I started playing with the input imp. I have Anderson humbuckers in one of my guitars. When I change the setting from auto 1M to just 1M I noticed a fairly dramatic dynamic range difference. Almost all amps responded much more to my hands. Not sure how or why but it put the 'feel' of vs 10 over the top.
 
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