I just found this one...
Does anyone see any problems with this one? Would this be a better choice?
I'd rather run it on 12v DC. Would that change anything?
Maybe use a different op-amp?
I could do without the pan-pot too.
Parts:
P1,___________100K Linear Potentiometer
P2_____________10K Linear Potentiometer
R1,R2,_________15K 1/4W Resistors
R3,R4,R11,R12_100K 1/4W Resistors
R5,R6__________22K 1/4W Resistors
R7,R8_________390K 1/4W Resistors
R9,R10________560R 1/4W Resistors
R13___________220R 1/4W Resistor
C1,C2_________330nF 63V Polyester Capacitors
C3,C8_________100µF 25V Electrolytic Capacitors
C4,C5__________10pF 63V Ceramic Capacitors
C6,C7___________4µ7 63V Electrolytic Capacitors
IC1___________TL062 Low current BIFET Dual Op-Amp
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Circuit description:
The schematic of this circuit is drawn as a stereo unit to better show the input Main Fader and Pan-Pot connections. The TL062 chip contains two TL061 op-amps into the same 8 pin case and is wired as two virtual-earth mixer amplifiers having a voltage gain of about 4, to compensate for losses introduced in the passive Pan-Pot circuitry. Therefore, total voltage-gain is 1.
Each channel added to the mixer must include the following additional parts:
P1, P2, R1, R2, R3, R4, C1 and C2.
These parts must be wired as shown in the above circuit diagram, connecting R3 and R4 to pin #2 and pin #6 of IC1 for Right and Left channel respectively. These IC1 pins are the "virtual-earth mixing points" and can sum together a great number of channels.
Notes:
Current drawing for one stereo Main Mixer Amplifier Module is 800µA.
Frequency response is 20Hz to 20KHz - 0.5dB.
Total Harmonic Distortion measured @ 2V RMS output = < 0.008% @ 1KHz; < 0.017% @ 10KHz.
THD is 0.005% @ 1V RMS output.
Maximum undistorted output voltage: 2.8V RMS.