This has been tested in circuit and produced audibly better results than the simple filter especially for medium and low sample rates. The musician may dial in the filter by ear between 15.1KHz and 1.8KHz to reduce or maximise aliasing as they see fit.
In order to implement this with a v1.0 PCB is possible but challenging. Would recommend sticking with the simple anti-aliasing filter there unless you are an intermediate or advanced solderer.
Construction notes
Although the circuit may seem difficult to implement on a v1.0 PCB, it is not as bad as it seems. The two 5.6K resistors and the 4n7 capacitor can be mounted directly to the dual gang pot. The 1nF can be connected on the solder side of the PCB, between pins 4 and 5 of U2b. This just leaves three flying leads to the pot - from U2a pin 1, U2b pin 5 and U2b pin 7.
The 82ohm and 100nF capacitor follow the same layout as the simple anti-aliasing filter and can be mounted to the solder side of the PCB board.
Don't forget a diagonal cut above the ADC (U1) pin 1 in order to cut the existing trace to U2a pin 1.
BOM
1 of 82ohm resistor
2 of 5K6 resistor
1 of 1nF capacitor
1 of 4n7 capacitor
1 of 100nF capacitor
1 of dual gang 47K or 50K log pot (sometimes called a stereo pot)
Using the unused U2b we may implement this 18dB/octave adjustable anti-aliasing filter:
https://www.dropbox.com/s/3snxq4brou7bscp/OAS%203rd%20order%20adjustable%20AA%20filter.jpeg?dl=0
This has been tested in circuit and produced audibly better results than the simple filter especially for medium and low sample rates. The musician may dial in the filter by ear between 15.1KHz and 1.8KHz to reduce or maximise aliasing as they see fit.
In order to implement this with a v1.0 PCB is possible but challenging. Would recommend sticking with the simple anti-aliasing filter there unless you are an intermediate or advanced solderer.
Construction notes Although the circuit may seem difficult to implement on a v1.0 PCB, it is not as bad as it seems. The two 5.6K resistors and the 4n7 capacitor can be mounted directly to the dual gang pot. The 1nF can be connected on the solder side of the PCB, between pins 4 and 5 of U2b. This just leaves three flying leads to the pot - from U2a pin 1, U2b pin 5 and U2b pin 7.
The 82ohm and 100nF capacitor follow the same layout as the simple anti-aliasing filter and can be mounted to the solder side of the PCB board.
Don't forget a diagonal cut above the ADC (U1) pin 1 in order to cut the existing trace to U2a pin 1.
BOM 1 of 82ohm resistor 2 of 5K6 resistor
1 of 1nF capacitor 1 of 4n7 capacitor 1 of 100nF capacitor
1 of dual gang 47K or 50K log pot (sometimes called a stereo pot)