opamp attenuate signal theory question

[panfilero]

hello,

i am trying to make an oscillator that I can plug into a guitar amp
(or keyboard or bass amp). i made an oscillator, but the amplitude of
the signal is way too big, 9 volts, i was wondering how i could bring
this signal down to the millivolts level (i think that's typical for
keyboard amps)..... could i just stick a resistor at the end of my
output.... for some reason I feel weird about doing that.... like
thinking that maybe I need a buffer in there, that if I do just put a
resistor at the output of my oscillator that that when i do hook the
circuit up to a load (the guitar amp) that it would change the
signal.... like it wouldn't be consistent but instead dependent on the
load..... could anybody help me out with this?

thanks
joshua

 

[Rich Grise]

hello,

i am trying to make an oscillator that I can plug into a guitar amp
(or keyboard or bass amp). i made an oscillator, but the amplitude of
the signal is way too big, 9 volts, i was wondering how i could bring
this signal down to the millivolts level (i think that's typical for
keyboard amps)..... could i just stick a resistor at the end of my
output.... for some reason I feel weird about doing that.... like
thinking that maybe I need a buffer in there, that if I do just put a
resistor at the output of my oscillator that that when i do hook the
circuit up to a load (the guitar amp) that it would change the
signal.... like it wouldn't be consistent but instead dependent on the
load..... could anybody help me out with this?

http://www.google.com/search?q=voltage-divider

Have Fun!
Rich

 

[Eeyore]

hello,

i am trying to make an oscillator that I can plug into a guitar amp
(or keyboard or bass amp). i made an oscillator, but the amplitude of
the signal is way too big, 9 volts, i was wondering how i could bring
this signal down to the millivolts level (i think that's typical for
keyboard amps)..... could i just stick a resistor at the end of my
output.... for some reason I feel weird about doing that.... like
thinking that maybe I need a buffer in there, that if I do just put a
resistor at the output of my oscillator that that when i do hook the
circuit up to a load (the guitar amp) that it would change the
signal.... like it wouldn't be consistent but instead dependent on the
load..... could anybody help me out with this?

You need a resistor like the one you mention AND another resistor to ground.
This makes a 'voltage divider' that attenuates the signal.

To attenuate from volts to millivolts you need a ratio of 1000:1.

I suggest you connect a 47k resistor to the oscillator output. Connect the end
of that to a 47 ohm resistor and connect the other end of the 47 ohm resistor to
ground. Take the signal from the junction of the two resistors.

Graham

To

 

[JosephKK]

panfilero [email protected] posted to sci.electronics.design:

hello,

i am trying to make an oscillator that I can plug into a guitar
amp
(or keyboard or bass amp). i made an oscillator, but the
amplitude of the signal is way too big, 9 volts, i was wondering
how i could bring this signal down to the millivolts level (i
think that's typical for keyboard amps)..... could i just stick a
resistor at the end of my
output.... for some reason I feel weird about doing that.... like
thinking that maybe I need a buffer in there, that if I do just
put a resistor at the output of my oscillator that that when i do
hook the circuit up to a load (the guitar amp) that it would
change the signal.... like it wouldn't be consistent but instead
dependent on the load..... could anybody help me out with this?

thanks
joshua

A resistor based divider is appropriate.