Subj : Re: Guitar cable
To   : Sven Petersen
From : MIKE ROSS
Date : Tue Jan 09 2001 04:10 pm

"Sven Petersen" wrote to "Neall Mercado" (08 Jan 01  23:00:57)
--- on the topic of "Re: Guitar cable"

SP> Well, the resistance of the cable doesn't matter a lot. It is very low
SP> anyway. A cable of 20 meters might have a resitance of 1 Ohm. And the
SP> input resitcance of an amplifier is at least some 100 000 Ohms. The
SP> loss caused by the resistance is not noticeable. What matters is only
SP> the low pass formed by the inductivity and capacity of the cable and
SP> the possible noise introduction due to a weak shielding.
SP> Take care

The cable inductance is negligible when compared to the pickup's own.
What makes a big sonic difference is the capacitance. In fact 100 K ohms
is a rather low amplifier impedance. An amplifier's input should be at
least 350 K ohms or more in order to preserve the pickup's clarity.

For example a dual coil pickup is designed, with respect to its stray
capacitance and inductance, to work best into about 250 K ohms and a
single coil pickup about half that value. So an amplifier input having
100 K ohms may be unbalancing the dual coil pickup's tone though less
for a single coil.

Cable capacitance however has a great effect on tone. One way to reduce
the effect of capacitance is to set the guitar's volume at mid rotation
(5) and turning up the amp's gain to compensate.

This in effect reduces the resistance on the cable to about 30 K ohms
and this value is much less affected by capacitance. For example with
0.001 uF cable capacitance with 30 K ohms forms a filter at about 5 K Hz
which has enough response to preserve tone clarity.

An often cited mod is to place a small cap between the volume pot's hot
terminal to the wiper contact. This will create a capacitive divider
which preserves clarity. However this only works well in a single spot.
The one side-effect is that at low volume it tends to boost the treble.
Values for this volume bypass cap vary in the range from about 100 pF to
0.001 uF and is ultimately dependant on personal taste.


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