Audio signal conditioning / protection circuit recommendations?

[cincin]

I'm starting to play with audio signals and filters and I'd like to use my computer's on-board sound card to do some frequency analysis Bode plots. I'm concerned about connecting my experiments directly into my computer, in fear of sending in DC or over-voltage by mistake.

I'm looking for an audio signal conditioning and protection circuit that would protect my sound card from my inevitable blunders. I've looked around, but signal conditioning is a broad subject with diverse applications, and I couldn't find a clear answer.

I know this will involve a 0.1uF to filter out any DC... and something like a 1V Zener to keep things under 1V (line level), is that even a thing? Do I need resistors or input and output impedance? I'm in the Beginners forum, right? good

Any help is greatly appreciated.
Good resources on that subject, or good places to search for circuits also appreciated.

[DimitriP]

Fancy front end :  http://www.pmillett.com/ATEST.htm   

[CountChocula]

Rod Elliot's website has a lot of good information on this subject (well, really, on anything that has to do with audio, including input protection).

A couple specific examples: Input Protection Circuits and PC Oscilloscope Interface, the latter of which I think does exactly what you're looking for.


—CC

[cincin]

Thank you!
Off to read all of that with my morning coffee.

[John B]

I know this will involve a 0.1uF to filter out any AC... and something like a 1V Zener to keep things under 1V (line level), is that even a thing? Do I need resistors or input and output impedance? I'm in the Beginners forum, right? good

Get that pesky AC out of my audio signal!

But seriously you'll probably just want to make a buffer op amp with input protection.

http://www.falstad.com/circuit/circuitjs.html?ctz=CQAgjCAMB0l3BWcMBMcUHYMGZIA4UA2ATmIxAUgoqoQFMBaMMAKACUQAWQzkbbQnzR8BUcFyrCq06AhYAnLjxGDC+FWLDxILACYhCGFBsPHOYQcd10AZgEMArgBsALnoPrzqz8Ushr9s4uDABedAB2dPLuply+BkZcFiBWto6uoRFRMZ7JangaqYGuLADuHgX8qolVUGUVcdVm8ToA5g2c8fkUYMbSLADGIDiCtSONmowFhLDYKOZk2BZ4GJBgxFCwa-WxnYLje3XlsWOitToA9gYGvFSckKQpMnCEKEiS19gs2AVUAGIQKgMYTCJggABqF1cdladBYQA

Something like this has always been sufficient for me. In your instance you may not even need a 1N4148 in series with a zener diode, 2x 1N4148 in series will clamp your voltage to somewhere around 1.2 volts.

[cincin]

Get that pesky AC out of my audio signal!

Derp!  hahaha yea, YOU KNOW WHAT I MEANT! haha. I'll go correct the original post to save what's left of my dignity.

Also, I love Falstad links. Thank you!