Blend circuit with boosts + feedback loop

squrl · Post by **squrl** » 28 Nov 2009, 23:24

i figured i would try my hand at a 'blender' type pedal with some useful additions, which include:
boosts in each split signal path (courtesy of soulsonic)
a simple feedback loop
phase inversion of the send/return path
running on a dual +9/-9v supply for increased headroom

i used fixed resistors for the boosts with a voltage divider at the end of those circuit portions for attenuation/boost - not sure if that's the best idea...
also, i wasn't 100% certain about using a voltage reference while also using a split supply - intuition tells me that the reference is half the supply so to send it to ground. not sure if i needed to 'float' the ground or something like that, though.

any comments are greatly appreciated as i'm sure there are some mistakes here...

fosnal1950 · Post by **fosnal1950** » 29 Nov 2009, 12:27

Why use U741 opamps , the Tl opamps are much higher quality.
I would make the 220K resistor a trimpot for more flexibilty to set your gain.

squrl · Post by **squrl** » 29 Nov 2009, 13:35

fosnal1950 wrote:Why use U741 opamps , the Tl opamps are much higher quality.
I would make the 220K resistor a trimpot for more flexibilty to set your gain.

ah forgot to add... the opamp values are only placeholders in eagle. i'll most likely be using a single LF412 in place of the two UA741 and a different quad than the TL084.

squrl · Post by **squrl** » 02 Dec 2009, 23:07

any ideas/suggestions before i hit the breadboard this week?