Alsamixer disable automatic gain control

This is my first time using alsamixer so my apologies if I am asking a stupid question. In my project I use a Raspberry Pi and a HiFiberry DAC ADC PRO+ to send data through a device, and record it back so I can analyze this. I ran into problems because of the AGC(Automatic gain control) that automatically transfers whatever signal is sent into it to a value between 0 and 1. I need to disable this but haven’t found this setting in the alsamixer, I typed alsamixer pressed F6 selected my device but I see no setting here that talks about the AGC. On the picture of another forum they talk about this setting being available. Anyone have any ideas?

Digirig is a USB audio interface for Amateur radio transceivers
Later comment on Digirig forum has a screenshot showing all 4 ALSA controls including AGC switch
Auto Gain Control in Linux? - #4 by eYeToEyeRob

Data Sheet for HiFiberry device does not show a switch for AGC in ALSA settings
Datasheet DAC+ ADC Pro | HiFiBerry
ALSA mixer control ADC for input gain should not change once it has been set by user
Data Sheet states device is using a Burr-Brown ADC but does not state which model of ADC
No mention of issues related to auto gain or auto level on HifiBerry forum