RP as sound processor cable adapter

[FlyingGazebo]

Hi,
I'm working on a project of using RedPitaya as a sound processor. Anyone ever tried interfacing her SMA connectors to a 3.5 or 6.35 jack? I think it should be pretty straightforward, since both are meant to work with coaxial cables, but truth be told, I haven't yet looked too deep into the issue.

Comments, ideas, warnings what I should be careful about ?

[Nils Roos]

I haven't tried it yet, but from a general engineering point of view there some things to note:

Electrically, you should be fine on the input side, the high impedance input circuitry is ok with standard audio outputs. Use averaging to improve resolution (14 bit isn't that much in the audio realm) and noise performance.

The outputs are designed for 50ohm termination, which you will have to provide in the form of an impedance matching circuit close to the signal sink. If you want to use dithering for improved output resolution, you will also need to add an averaging filter to that circuitry.

I would be very interested to hear of your progress in that regard.

[FlyingGazebo]

I expect a regular hi-fi (that I was planning on using as amplifier) has high input impedance on aux input? So I need to match 50 Ohm to about 1 MOhm?

[Nils Roos]

Sounds about right, yes.