atcomsystems.ca/forum Forums Computers & Programming Computers, Software, Accessories Laptop Audio Output to Stereo Input?

Hal -

I think I'm following this. But you're saying that on a consumer amp the mic input will be 10K?

I've got very little recent experience with consumer stuff. But commercial amps all list their mic inputs much, much lower.

Are they lying? Is this really not an issue anymore? I just (18 months ago) did a huge PA job at JFK airport and impedance mismatches WERE a factor. Was it just that equipment? I know it used to be a real issue.

I know when I've connected a telephone system (600 ohms) to an aux input (15K ohms) I always get much better sound quality with a Bogen WMT-1.

I'm confused.

Sam

The audio sounds great on a headset plugged into the laptop so I assume the quality is ok.

But I understand what you are saying, I've discovered that if the picture is trashy on the laptop monitor it will be trashy on the tv. with the s-video cable.

I'm confused too...my Mackie mixer manual says that the mic impedance is 1.3K and line level impedance is 10K or greater. Then I looked at a Bogen mixer/amp manual and it said 200 ohms for a mic input. That's quite a difference.

Jeff there are 2 different mic impedances low and high. The Mackie 1.3K input would most likely work with either impedance where the Bogen input is for Low Z mic only. Hi Z mics are 2 conductor where a Low Z mic can be a balanced line it has 2 audio conductors and a separate shield this works better for long distance cables just like a balanced phone line.

Traditionally microphones (at least real microphones) are 150 ohms balanced. It used to be in the old days that a mixer mic input would have an input transformer with a primary impedance of 150 ohms to exactly match that mic impedance. 600 ohm lines were expected to work into a 600 ohm impedance. That isn't done anymore.

Take a look at this Rane Note that explains it better than I can.

-Hal

These are the microphones I use every day at work.
https://electrovoice.com/products/59.html
It says they are 600 ohms, low impedance, and balanced.

Yup, 600 ohms. Just goes to show how it's all changed.

-Hal

Hal-

Thanks a lot. This is what happens when you start your education working with tube amps. You learn something and it's gospel.

I still think you do better to plug an auxiliary device (ipod, cd player, etc) into an aux input and leave the mic inputs for miocrophones. IMHO it produces a better sound.

But that's probably because I'm a cranky old guy.

Sam

No, you are absolutely right. It doesn't make sense to attenuate a signal down just to amplify it back up when you can go in directly. Although audio electronics is very clean today, it still can add unnecessary noise and distortion IMO.

You would be surprised though at some professional equipment that just switches a pad in and out to make a mic input an aux input. But, like I said, it's easy today to design audio stages with hardly any noise and distortion.

-Hal

Here's another good article I found:
https://www.tape.com/resource/impedance.html