I believe you may be confusing voltage levels with impedance. 600 ohms has NOTHING to do with it beyond defining the voltage present in a circuit where levels are defined in dBm. dBm means dB with respect to 1 mW, where the impedance must also be defined. dBu, the current most common reference in pro audio, is defined as the voltage with respect to 0.78 volts, independent of the circuit impedance. Of course, 0.78V corresponds to 0 dBm in 600 ohms.
There are also issues about how digital guys think about level and how analog guys think about level. Digital folks tend to think of absolute maximum peak levels -- all the bits on, digital clip. This corresponds roughly to 100% modulation of an AM transmitter. But audio levels are DEFINED as the RMS value of a waveform. That 13 dB difference you are talking about is the approximate difference between RMS and peak of an uncompressed audio waveform. Both ways of thinking/talking about it are important, but you absolutely must understand the difference. Jim Brown K9YC http://audiosystemsgroup.com --Original Message Text--- From: [EMAIL PROTECTED] Date: Fri, 2 Jul 2004 07:30:49 EDT 600 ohms is still very much the standard. _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
