Quote:
Originally Posted by Hybrid tellies
Thank you for your helpful comments. I can now clearly understand why they used a 500 ohm line output impedance. Interesting to know that this is what came before the 100v line audio feed systems.
As for the 5000 ohm feed I guess is that most headphones of the day were higher impedance compared to what we have today.
Again many thanks for your help.
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500ohm is a reasonable match for open wire telephone lines which is probably why it was chosen. 100V line "impedance" depends on how many watts are available from the source amplifier..
Old style headphones were typically 2000 ohm which isn't too bad a match for a 5000 ohm output, though with p-p 6V6s, you'd need to watch the volume control!