Blend Board is a simple way to add a mix control with analog DRY path to any DSP board. It’s also useful as an input buffer for connecting a guitar directly to adau1452 board.
Wiring
SND: SEND output. This is the buffered signal, it should go to input of DSP.
RTN: RETURN input. The signal from DSP output should go here.
Pot BLEND: mixes DRY and WET signals.
Pot VOLUME: controls output level.
R5
This resistor sets the gain of the output stage:
R5=100K -> gain=2
R5= 1M -> gain=11
Partlist
| Part | Value |
| R1 | 100K |
| R2 | 100K |
| R4 | 100K |
| R6 | 100K |
| R5* | 100K |
| R5* | 1M |
| R7 | 1M |
| R3 | 1M |
| C8 | empty |
| C* | 100p |
| C1 | 1u |
| C2 | 1u |
| C4 | 1u |
| C5 | 1u |
| C7 | 1u |
| C6 | 10u |
| C3 | 47u |
| IC1 | TL072 or equivalent |
| BLEND | 100K LIN |
| VOLUME | 100K LOG |
| * To increase high frequency roll-off place a 100pF cap in parallel with R5 | |
| * Use 100K for ouput gain=2, use 1M for ouput gain=11. |
