a_zee Posted January 28, 2019 Posted January 28, 2019 If my amp spec sheet says headphone out is 25 mW / 8 Ω , and my headphone is 600 Ω, does that mean my amp output is 600/8 * 25 = 1.875W when powering the 600 Ω cans?
mwhouston Posted January 28, 2019 Posted January 28, 2019 But what is the effciency of the two phones?
a_zee Posted January 28, 2019 Author Posted January 28, 2019 (edited) 33 minutes ago, mwhouston said: But what is the effciency of the two phones? They're Beyerdynamic T1 (1st Gen) in the example FYI. The amp in question is this one: https://audio-heritage.jp/SONY-ESPRIT/amp/ta-f555esx.html (use Chrome to translate the page if necessary). How did you get the 3mW figure anyway? Edited January 28, 2019 by mexicoke68
Volunteer sir sanders zingmore Posted January 28, 2019 Volunteer Posted January 28, 2019 25mW into 8 ohms 12.5mW into 16ohms 6.25mW into 32 ohms 3.125 mW into 64 ohms ~1.6mW into 128 ohms ~0.8 mW into 256 ohms ~0.4mW into 512 ohms so roughly 0.3 into 600
a_zee Posted January 28, 2019 Author Posted January 28, 2019 (edited) 15 minutes ago, Sir Sanders Zingmore said: so roughly 0.3 into 600 Wouldn't that be severely under powered? With this amp, the volume dial is at 20% with the 600 ohm Beyer T1s connected in the headphone jack and it's so damn loud my ears feel like they're about to explode. Edited January 28, 2019 by mexicoke68
aasza Posted January 29, 2019 Posted January 29, 2019 (edited) On 28/01/2019 at 1:47 PM, mexicoke68 said: Wouldn't that be severely under powered? With this amp, the volume dial is at 20% with the 600 ohm Beyer T1s connected in the headphone jack and it's so damn loud my ears feel like they're about to explode. The Beyerdynamic T1 have a HIGH sensitivity level of 102dB SPL/V The HIGHER the sensitivity the LESS power required to drive your cans to a loud volume 0.03mW will provide your 600Ω headphone 85dB of SPL (Sound Pressure Level a.k.a Listening Loudness) Safe 85 dB SPL 0.14 Vrms 0.23 mA 0.03 mW Moderate 100 dB SPL 0.79 Vrms 1.32 mA 1.04 mW Fairly Loud 110 dB SPL 2.51 Vrms 4.18 mA 10.5 mW Very Loud 115 dB SPL 4.47 Vrms 7.45 mA 33.3 mW Painful 120 dB SPL 7.94 Vrms 13.23 mA 105.07 mW Edited January 29, 2019 by aasza 1
Volunteer sir sanders zingmore Posted January 29, 2019 Volunteer Posted January 29, 2019 110dB isn’t “fairly loud” , it’s f**king loud. Will-damage-ears loud if you listen at that volume for more than a couple of minutes
aasza Posted January 29, 2019 Posted January 29, 2019 (edited) 9 hours ago, Sir Sanders Zingmore said: 110dB isn’t “fairly loud” , it’s f**king loud. Will-damage-ears loud if you listen at that volume for more than a couple of minutes Best stick with Safe Mode then Edited January 29, 2019 by aasza
a_zee Posted January 30, 2019 Author Posted January 30, 2019 15 hours ago, aasza said: The Beyerdynamic T1 have a HIGH sensitivity level of 102dB SPL/V The HIGHER the sensitivity the LESS power required to drive your cans to a loud volume 0.03mW will provide your 600Ω headphone 85dB of SPL (Sound Pressure Level a.k.a Listening Loudness) Safe 85 dB SPL 0.14 Vrms 0.23 mA 0.03 mW Moderate 100 dB SPL 0.79 Vrms 1.32 mA 1.04 mW Fairly Loud 110 dB SPL 2.51 Vrms 4.18 mA 10.5 mW Very Loud 115 dB SPL 4.47 Vrms 7.45 mA 33.3 mW Painful 120 dB SPL 7.94 Vrms 13.23 mA 105.07 mW Ahh this explains it. I was fooled by thinking high impedance headphones would mean hard to drive. Turns out I got to factor in sensitivity as well? Could you explain why 85 -> 100 dB SPL results in a massive jump from 0.03mW to 1.04mW, and so on. Why the non-linearity?
aechmea Posted January 30, 2019 Posted January 30, 2019 1 hour ago, mexicoke68 said: Could you explain why 85 -> 100 dB SPL results in a massive jump from 0.03mW to 1.04mW, and so on. Why the non-linearity? dBs are a ratio expressed as logarithmic not linear. For power units dB = 10 log(p1/p0) so 3dB = approx double 10dB = 10 times 15dB = approx 31.6 times 20dB = 100 times 30dB = 1000 times The ear is non linear too. 10dB sounds about double loudness but needs 10 times the power. 1
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