Impendence adjuster: from Line to Instrument

[mr.adambeck]

I'm looking for something that will take a keyboard or line out and adjust the impendence and volume to one suitable for guitar effects and guitar amps.  The simpler the better.  Any suggestions?

[Lurco]

adjustable: 100k log pot,
keyboard output into clockwise lug, effect input from wiper, counterclockwise lug as common ground.
simple: 2 resistor voltage divider,
next poster will give values.

[mr.adambeck]

I'm sorry, I think I'm too much of a noob to understand what that meant.  Could you please explain it in idiot terms for people like myself? 

[grapefruit]

Hi,

This might help...
http://en.wikipedia.org/wiki/Voltage_divider

That's the two resistor method.
A rough guess of values would be 10k for Z1 and 1k or 2.2k for Z2. I often use 1/8 watt resistors and put them in the jack plug.

If you want to use a pot the two resistors are replaced by the pot. Just connect it up so the Vin goes to CW of pot, V out is wiper, and Gnd goes to CCW.

BTW: You don't have to worry about impedance, other than the input impedance of your voltage diver should be at least 10k. That's why I chose 10k for R1 (Z1). If you use a 50k pot that's fine too.

Cheers,
Stew.