two headphone outs
Mar 20, 2009 at 5:41 AM Thread Starter Post #1 of 7

esien

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hi
should plugging in 2 pairs of headphones at the same time into my Home Amp effect the sound? one headphone is 300 ohm and the other one is 40 ohm.

Also when i have the amp on for a long time, it feels that unclean power is left at the headphone's driver or something... when i switched it off i can hear power current clears out. is it normal?
 
Mar 20, 2009 at 3:31 PM Post #3 of 7
Quote:

Originally Posted by esien /img/forum/go_quote.gif
hi
should plugging in 2 pairs of headphones at the same time into my Home Amp effect the sound? one headphone is 300 ohm and the other one is 40 ohm.

Also when i have the amp on for a long time, it feels that unclean power is left at the headphone's driver or something... when i switched it off i can hear power current clears out. is it normal?




Those two headphones have a pretty widely different impedance; I'd say you probably shouldn't have them both plugged in at the same time for best sound. And the 40ohm headphone may be getting driven much too loudly when you're listening to the 300ohm can.

When you turn the amp off it takes a few moments for the power supply caps tpo deplete. During that time you'll likely get some whooshes or thumps; that's normal, I wouldn't worry about it.
 
Mar 21, 2009 at 3:07 AM Post #4 of 7
thank you very much for the answer
i have one more question. can i then plug in headphones of 40ohm and 50ohm at the same time without effecting the sound?
how about the rear outputs?
 
Mar 21, 2009 at 8:44 AM Post #5 of 7
Quote:

Originally Posted by esien /img/forum/go_quote.gif
thank you very much for the answer
i have one more question. can i then plug in headphones of 40ohm and 50ohm at the same time without effecting the sound?
how about the rear outputs?



Depends on their sensitivity. Try it and see - the volume may match reasonably well, and it may not. The other thing you can do to see how the sound is affected is to listen to each headphone individually with and without the other plugged in and see if you notice anything.
 
Mar 22, 2009 at 4:01 PM Post #6 of 7
If the sensitivities are the same would building an adapter with an in line resistor of about 2 watts and 350 ohm on both the left and right channels solve the problem of different volumes?
 
Mar 22, 2009 at 4:16 PM Post #7 of 7
Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif
If the sensitivities are the same would building an adapter with an in line resistor of about 2 watts and 350 ohm on both the left and right channels solve the problem of different volumes?


Eh, I hate the way they measure headphones. Efficiency, as usually measured, doesn't help much. Personally, I think headphones should be measured by volts RMS for 90dB with pink noise.

To answer your question, if you add a resistor you'd effectively be changing the efficiency. And you'd be fine with small 1/4 resistors easily.

Probably the best solution is something like this, unless you're picky, in which case you should just buy a second pair of headphones that match.
 

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