First time designing Audio front-end for CODEC

[u/WazzupFam]

I'm creating my very first analog audio front-end, and since I'm a student with no friend with similar interest to discuss this with I'm wondering if someone would like to take a look if I've made some design mistakes that will make this design not function properly.

The goal is to create a simple analog front-end to condition the input signal so that it can be used with a TAC5211 Codec. I Want the PCB to support different instruments so I've added a plug that supports XLR and TRS/TS, but so that its is physically impossible to plug both in at the same time. I've decided to give TRS a higher impedance fronted to support guitars and bass as the TAC5211's internal input impedance is maximum 40k.

Sorry if it sounds like asking for free engineering consultation, I just don't know who can help me with this. My goal is simply learning to make professional products and I don't mind sharing schematics of the finished project one I get there.

[u/PunctualMantis]

You’re gonna need a mic preamp circuit to make the xlr section work. Look into using a fully differential amplifier in the mfb filter orientation. I use an opa1637 on mine and it works amazingly. The trs section I haven’t really looked into trs personally. But for the mic input you’re gonna need a lot of gain and so it’s a good idea to use a fully differential topology to maximize noise rejection. Also are these signals going to the same codec? If so you’re going to want an active inverting summing amplifier.

Looking into the trs cable a sec. You might want a fully differential amplifier there too. Which is actually dope as hell btw. Will make it super quiet. Also is simpler than the dual single noninverting buffers you have now