A crisp OLED display.

Winstar WEH1602A for a PGA2311 volume control. After altering the jumpers on the back it proved to be a drop-in replacement

See picture. Jumpers/devices JF, CFR, J15, JCS and CSH are empty. CSL is connected (re-use 0 Ohm smd). Pins 3,15, 16 are not connected.
(No changes to the initialization procedure. Aliexpress search: WEH001602A 16x2 COB OLED Character Display 5V WS0010 Controller)

Tweaks

The Yuan Jing pga2311 volume control was tweaked by seperating the digital and the analog ground. They are connected near the PGA2311 (black wire over IC). Extra power line buffering was added. The digital section has it's own dedicated 5Volts power supply. For the lowest distortion a NE5532 buffer is placed between the input relay's and the PGA2311. To make sure that the source impendance to the PGA2311 is always low regardless of the source. The NE5532 exhibits above 2kHz substantially lesser distortion than the often used BurrBrown OPA2134.