How best to control input level?

[Dave Varner]

I'm toying with a NIGC, 220 ohm input resistor followed by 22k to ground. 22k feedback with 680 to ground on the other side of the circuit. No caps, no pot, plain simple in a nice $9 Container Store wooden box. Not exactly a PD icon, more of a "Timex" or "street corner Rolex" version.

With my 96db fullrangers and Foreplay preamp, the lowest volume setting is too loud.

I'd like to change the 220/22k at the input to lower the volume, which resistor(s) is it best to adjust? I understand the 22k is there to improve stability, is there any magic to the relationship of the two?

Thanks from a rookie that's trying to learn,

DV

[GregGC]

Originally posted by Dave Varner
I'm toying with a NIGC, 220 ohm input resistor followed by 22k to ground. 22k feedback with 680 to ground on the other side of the circuit. No caps, no pot, plain simple in a nice $9 Container Store wooden box. Not exactly a PD icon, more of a "Timex" or "street corner Rolex" version.

With my 96db fullrangers and Foreplay preamp, the lowest volume setting is too loud.

I'd like to change the 220/22k at the input to lower the volume, which resistor(s) is it best to adjust? I understand the 22k is there to improve stability, is there any magic to the relationship of the two?

Thanks from a rookie that's trying to learn,

DV

22k/680 will give you the gain of the amp. You can increase the 680 res. but as far as I remember there was an optimum gain for a power amp of 22 to 30 dB. Which means 1K should be the max if you want to follow that requirement. If 1K is not enough, increase the 220 ohm input res. and until you get enough division ratio and the signal is low enough.

/Greg