[endia]

I found a modified CMOY schematic which has interesting gain resistor values. Original schematic at here;
http://www.raymondaudio.nl/projects/...7/ampschem.pdf

I modified it to basic CMOY version (for gain 5) and tried on breadboard, but I can't sure what i'm doing while changing res. values. Is it free to vary proportional values, or is it an impedance problem?

And what your things about adding R2?
Thanks...

 

[guzzler]

R3 and R4 can be changed easily, preferably leave R3 at around 1K and vary R4...

R2 controls the input impedance to the opamp and is probably worth keeping in...

g

 

[endia]

thanks guzzler, but i mean; changing vaues while keeping ratio..
can increasing R4/R3 values (100K/10K, like above schematic) cause impedance problem?
thanks