Input attenuator for Cosmos ADC/soundcard

26 July 2023

Cosmos ADC its a great tool from DIY users, even so, the low input impedance it's a problem for some devices line dac's or line preamplifiers.

For that i designed a simple input attenuator to be used not only with Cosmos ADC but with any sound card to.

The attenuator specs:

6dB steps from +6dB (yes, it amplify too) to -36dB
input impedance 100Kohm SE and 200Kohm balanced
dimensions 129.3 mm* 65.3 mm
will be controlled via I2C by arduino via rotary encoder an will send to PC the actual attenuation for setting the FS

Post will be updated as log the project will progress.

Regards!