600 ohm

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http://www.mpaudiovisual.com
Member Since: Jul 13, 2007

Could somebody explain to me what is 600 ohm load means in audio? Is it at the input?

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The Czar of BS
Member
Since: Dec 31, 2007


May 04, 2009 11:27 pm

Fren hie! Where the hell have you been hiding all this time?

Either way, good to have you back.

The difference that you are looking for, and yes it is a difference. Is dBu, or dBm.

On some Opamps, you need a 600 ohm load for the Opamp to drive, or even turn on.

The other needs to see a 10K ohm load.

All this is for is setting up the gain structure in your preamp, or output.

The simplest explanation that I can give is, that high ohm load equals high gain.

For an example, a regular pair of headphones can not be plugged into a DVD output. But, a 600 ohm load headphones can.

Does that help at all?

The Czar of BS
Member
Since: Dec 31, 2007


May 04, 2009 11:32 pm

This link will try to help. How's your math skills?

stason.org/TULARC/enterta...dBV-dBm-dB.html

http://www.mpaudiovisual.com
Member
Since: Jul 13, 2007


May 05, 2009 04:40 pm

Hey Rob,

I knew you would answer that one ;)


For some reason I couldn't login here anymore I had another nickname that I used but I loged in with my old nickname and its working,

I haven't been around for a while studying electronics right now... pretty hard That's what I am trying to figure out the good ole 600 ohm audio line

Here's a link that I found

www.audiodesignline.com/s...cleID=196800735


What I don't understand is that 600 ohm doesn't dictate the impedance, does it mean that soon as the signal hits the audio input there's 600 ohm in resistance??

The Czar of BS
Member
Since: Dec 31, 2007


May 05, 2009 04:55 pm

This came about because of Alexander Gram Bell. When he first made his telephone, he used .707, or the rms value of 1 volt to be the drive voltage.

Starting to see it now?

Because he used such a low voltage for the transmission, you need to have a high impedance in the line so that it will not oscillate. And it needs to be matched at both ends.

The Czar of BS
Member
Since: Dec 31, 2007


May 05, 2009 05:08 pm

Oh, I didn't read the rest of the question all the way through. Sorry, I have the flu.=)

By having the impedance matched at both ends, the driver views the resistance as the 600 ohm load. Remember, impedance changes with frequency.

The line at a 1K tone will seem to be a 600 ohm load to the driver.

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