Unmasking headphone-jack specs from Yamaha receivers
May 21, 2015 at 3:57 PM Thread Starter Post #1 of 3

Me x3

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I've read (at least 10 times) people trying to figure out how to read the headphone-jack (PHONES) specs from typical Yamaha receivers and speaker integrated amps.
 
Examples:
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Yamaha A-S500 Integrated Amplifier:
PHONES jack rated output/Impedance
CD, etc. (Input 1 kHz, 200 mV, 8 Ω) ....................  430 mV/470Ω
 
Manual: http://download.yamaha.com/api/asset/file/?language=en&site=usa.yamaha.com&asset_id=45663 (Specs on page 21)
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Yamaha RX-V473 AV Receiver
Headphone Jack Rated Output / Impedance
AV 5 etc. (1 kHz, 50 mV, 8 Ω) .............................100 mV/470Ω
 
Manual: http://download.yamaha.com/api/asset/file/?language=en&site=usa.yamaha.com&asset_id=54240 (Specs on page 102)
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These are quite tricky specs, specially when compared with typical headphone amp specs like those from Schiit Audio or Fiio.
 
I contacted Yamaha a few times to clarify them, so I share the gathered information.
 
For Yamaha A-S500:
 
"CD, etc. (Input 1 kHz, 200 mV, 8 Ω)" refers to the conditions under which the 430 mV/470 Ω rating was gathered. Basically, a 1kHz test tone was input through the "CD" input at 200mV. Since the headphone output is tapped off the amplifier, it is affected by the impedance selector switch. So the "8 Ω" portion of the rating indicates that the impedance selector switch was set to the "High" position during the test."
 
470Ω is the output impedance of the headphone jack.
 
Same logic applies to RX-V473 specs:
 
Input signal at AV5: 1kHz tone at 50mV
Output signal at headphone jack: 100mV
Output impedance: 470Ω
 
"8 Ω" means the impedance selector switch was set to the High position
 
Well that's pretty much all the information I have so far.
 
I wonder why Yamaha uses 50mV and 200 mV input signals to rate the headphone jacks when most DACs and CD Players line outputs normally goes up to 2 Vrms (maybe I'm missing something here)
 
I've made this question to Yamaha, hopefully there will be an answer soon.
 
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There aren't many good matches for this headphone jacks.
Low impedance headphones tend to sound very diffuse and some of them really colured when plugged into a jack with 470Ω output impedance. High impedance headphones are reccommended.
 
That said, even the 250Ω Beyerdynamic DT880s suffer from a slight coloration when plugged into my Yamaha A-S500, since 470Ω is a really high output impedance.

In this particular case, the result is a slightly warmer sound that can be labeled as 'more musical'
DT880s are a good match for these amps since their impedance doesn't vary a lot across the spectrum and the added bass might be a good thing for some.
 
DT990 are similarly good pair electrically, main difference is that the added warmth might not be something you'd want since DT990s are already warm with raised mid-bass. (Down to preference)
 
Sennheisers HD600/HD650/HD800 typically have a big raise in the impedance plot around 100Hz, so, not that great since the pairing singificantly change the frequency response and the overall performance of these headphones.
 
Same applies to the 600Ω Beyer T1, the impedance plot goes up to 1400Ω at 100Hz, so the frequency response changes when plugged into the Yamaha. It becomes too warm for my tastes and fail to show its very detailed presentation.
 
 
Hope this helps! Feel free to share your views!
 
Me x3
 
May 23, 2015 at 9:12 AM Post #3 of 3

caml

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Hi and thanks for the good thread idea.
 
In all honesty before getting my Asgard 2 I was using the A-S500 HP out with my DT770 Pro 80 ohms (mainly, but other HP too) and it sounded fine. Warm, perhaps a bit soft, but really not bad at all, not unpleasant for sure IMHO. And not as bad as reading the specs might lead you to believe. Sure I'm happier with the Asgard 2, but the difference isn't night and day, it's the kind of improvement that you feel over the course of several songs. Asgard 2 is a bit more refined, and slightly more sub-bass able, but that's it.
 

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