Headphone impedance matching (with a Y-splitter)
Apr 10, 2013 at 7:01 AM Thread Starter Post #1 of 7

Tassen

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I searched around for a while on the forums but didn't see this particular variation of the question answered anywhere.
 
From the other threads I've gathered that by plugging two headphones of different impedance into a splitter, you'll run into volume issues.
My question is about what impedance differential between the headphones is "acceptable".
 
I have a set of Denon D2000s.
They are 25 ohm.
I'm going to buy another set of headphones for my wife so we can watch movies.
I've been shopping for a 32 ohm set (Beyerdynamic 770 or 990) because I figure a 7 ohm difference will be negligible.
I've also assumed a 16 ohm set would be fine (Beyerdynamic Custom One).
 
But could I get an 80 ohm set and still be fine?
 
My receiver output jack is 100 ohm (in case that matters).
 
Thank you for your input!
 
Apr 10, 2013 at 7:31 AM Post #2 of 7
Quote:
Originally Posted by Tassen /img/forum/go_quote.gif
 
My receiver output jack is 100 ohm (in case that matters).

 
If that is the output impedance, then a higher impedance headphone would actually be louder (ignoring efficiency, which is however better in the case of the D2000, so it would still be louder because of that). But that is only relevant if there is no splitter and only a single headphone is driven; with the splitter, the headphones are connected in parallel, and the voltage is the same on both. Therefore, in that configuration, the D2000 is the loudest, and the various DTxx0 will have decreasing loudness with increasing impedance.
 
If the receiver can output enough voltage, then I would choose the 250 Ω DT770/990, and use a modified splitter with resistors on the D2000 to equalize the volume (the simplest solution is ~91 Ω serial resistors). The ideal (but not so cheap) solution would be a headphone amplifier with a separate volume control for each headphone.
 
Apr 11, 2013 at 3:02 AM Post #4 of 7
Quote:
If the receiver can output enough voltage, then I would choose the 250 Ω DT770/990, and use a modified splitter with resistors on the D2000 to equalize the volume (the simplest solution is ~91 Ω serial resistors). The ideal (but not so cheap) solution would be a headphone amplifier with a separate volume control for each headphone.

 
Thank you for the feedback.
Are you doing the math or have you run headphones of differing impedances through a splitter before?
 
Do you think the D2000s with 80 ohm DT770s using an unmodified splitter straight from the receiver would result in a large volume differential?
 
 
Apr 12, 2013 at 1:33 PM Post #6 of 7
Quote:
Monoprice has a headphone splitter with seperate volume controls. I'm not sure how good it is, but it's just a couple dollars plus shipping.

Curious.... why does that have a 1/8 TRRS plug?  I have never seen a 1-in / 2-out headphone splitter with this.
 
???
 
OP I really think its the sensitivity/efficiency matching that is far more important than impedance matching.  I can plug my K701 and KSC75 (IIRC they're both ~65 ohms) into a Y splitter and dam near blow up the koss at K701 levels. 
 
Apr 13, 2013 at 4:53 AM Post #7 of 7
Quote:
OP I really think its the sensitivity/efficiency matching that is far more important than impedance matching.  I can plug my K701 and KSC75 (IIRC they're both ~65 ohms) into a Y splitter and dam near blow up the koss at K701 levels. 

 

I should be okay on sensitivity - only a 10 dB difference between the two.
(Right?)
 

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