[sdiy] Serge CV input circuit?

[Grant Richter]

Use this, all resistors and pots are 100K
Explanation: When op-amp plus is connected to input, it is gain of 1
follower. When plus input is grounded it is gain of -1 inverter.

input
                          A
 *---/\/\/\----+------\/\/\/\/\---+
 |             |                  |
 |             |   |\             |
 |             |   | \            |
 |             |   |  \           |
 |             +---| - \          |
 |                 |    \         |
 |                 |     \        |
 |                 |      \       |
 |                 |       \      |
 |                 |        \     |
 |                 |         >----+--->
 |                 |        /     output
 |                 |       /
 |                 |      /
 \                 |     /
 /                 |    /
 \<----------------| + /
 /                 |  /
 \                 | /
 /                 |/
 \                
 |           
 |           
GND