Re: Connecting Headphones in Parallel With a Speaker

Richard Crowley · 2007-12-03T15:53:35+00:00

Similar things have been done perhaps since before you were born.3K is very high for this application. You don't really needany series resistance to prevent overpowering the headphonesince it is such high impedance already (compared to thespeakers). However resistance on the order of 100 ohms(or higher, up to 1K for modern higher-impedance headphones)is frequently used as a form of attenuation. Most power ampsare rather noisy, but you don't hear the noise because youdon't listen to speakers with you ear against the grille. Butwhen you directly connect headphones to the power ampoutput, you will likely hear this low-level noise. Attenuatingthe audio with a series resistor is a cheap way of dealingwith this issue.

Dec 03, 2007 23 Replies

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GregS 18 years ago

Its my guess, its good to stay away from driving Z's 1 to 3 times the nominal headphone Z. Lower and you get constant voltage, and much higher you get constant current feed. This I am thinking will minimize impedance responce errors.

greg

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Don Pearce 18 years ago

OK - wasn't even half concentrating.

Pearce Consulting http://www.pearce.uk.com

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Arny Krueger 18 years ago

I have the impression that headphones are designed to work in range from no higher than matched impedance to constant voltage. Hi-Z phones tending more towards constant voltage, and Lo-Z phones more like matched impedance.

In the case of HD-580s, I am comfortable with source impdances from about 80 ohms to 16 ohms to minimum.

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GregS 18 years ago

There is a lot of variation among the Z plots from that web page. i'll have to study them some more.

greg

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