Beyerdynamic DT 770 PRO Black Edition (80Ω): how much amplifier do you need?

The Beyerdynamic DT 770 PRO Black Edition (80Ω) is 80Ω. Its maker prints a sensitivity of 96.0 dB and never says whether that is per milliwatt or per volt, so this page reads it as per milliwatt — on that reading it needs 2.5 mW to reach 100 dB SPL, or 0.45 V across the drivers. If the figure is really per volt, it needs far more.

That puts it in the easy category. A phone, a laptop headphone jack or the cheapest USB dongle will drive it to painful levels. Of the 280 sources in the database, 253 have at least 10 dB of headroom and another 27 have enough. The cheapest portable source that does the job is the Apple USB-C dongle (US) at $9.

The two numbers that decide everything

Impedance80 Ω
Sensitivity (printed with no reference unit)96.0 dB
Sensitivity (voltage) (if the figure is per milliwatt)107.0 dB/V
Power for 100 dB SPL (if the figure is per milliwatt)2.5 mW
Voltage for 100 dB SPL (if the figure is per milliwatt)0.45 V
TypeOver-ear
Easy to drive — anything will do it
All 280 sources at 100 dB SPL into 80Ω
Comfortable 253Enough 27Marginal 0Not enough 0
Cheapest portable source that does it
$9 · USB dongle · +7 dB headroom
Cheapest desktop amp with 10 dB to spare
$75 · desktop DAC/amp · +14 dB headroom

This maker printed a decibel figure and no reference unit, so the number above is shown exactly as printed. Everything below reads it as per milliwatt, which is the commoner convention on a sheet that omits the unit — if it is really per volt, this headphone is about 11 dB harder to drive than the rest of this page assumes. The converter explains the difference.

Where this sensitivity figure comes from

Beyerdynamic publishes a sensitivity of 96 dB and does not state whether that is per milliwatt or per volt — the spec sheet simply stops at the number.

Both readings are given here so you can judge for yourself. If that 96 dB is per milliwatt, the figures on this page are right as they stand. If it is per volt, the real sensitivity is 85.0 dB/mW — 11 dB lower at 80Ω — and everything above understates what these need by that much. The per-milliwatt reading is the one shown, because it is the more common convention on a spec sheet that omits the unit; treat it as an indication rather than a specification.

Source: north-america.beyerdynamic.com. How this data was built.

What is printed there, and what it is worth

As it is labelledAs printedToleranceStandard
Headphone frequency response5 - 35.000 Hznot printednot printed

Beyerdynamic prints 5 - 35.000 Hz for the Beyerdynamic DT 770 PRO Black Edition (80Ω), under the heading “Headphone frequency response”. Source: north-america.beyerdynamic.com.

Beyerdynamic prints the top of this range as “35.000”, with a dot, on the same English page where its other models get a comma. The figure is quoted here as it stands.

No tolerance is printed with it, so “5 - 35.000 Hz” says nothing about how loud this headphone actually is at 5 Hz.

Only what the maker printed; maker by maker.

Power, voltage and current by listening level

LevelWhat it isPowerVoltageCurrent
85 dB SPLquiet background listening0.08 mW80 mV1.0 mA
95 dB SPLnormal listening0.79 mW0.25 V3.2 mA
100 dB SPLloud listening2.5 mW0.45 V5.6 mA
105 dB SPLvery loud7.9 mW0.80 V10.0 mA
110 dB SPLpeaks on dynamic music25 mW1.42 V17.7 mA

Most people listen between 75 and 85 dB; the 100 dB row leaves room for peaks.

The cheapest sources that drive them with room to spare

The 15 cheapest of the 280 sources here that reach 100 dB SPL into 80Ω with at least 10 dB of headroom and no known hiss or output-impedance problem with these headphones. All 280 sources, judged for these headphones.

SourceTypePricePower into 80ΩHeadroomVerdict
FiiO KA11USB dongle$2980 mW+15 dBComfortable
Tanchjim Stargate IIUSB dongle$4030 mW+11 dBComfortable
ddHiFi TC35ALUSB dongle$4684 mW+15 dBComfortable
ddHiFi TC35AirUSB dongle$4684 mW+15 dBComfortable
Fosi Audio N3Bluetooth receiver$5055 mW+13 dBComfortable
Hidizs SD2USB dongle$5028 mW+10 dBComfortable
FiiO BTR13Bluetooth receiver$5940 mW+12 dBComfortable
iFi GO linkUSB dongle$5932 mW+11 dBComfortable
Kiwi Ears Allegro ProUSB dongle$6027 mW+10 dBComfortable
Tempotec Sonata BHD ProUSB dongle$60112 mW+16 dBComfortable
ddHiFi TC35Pro (Mountain2)USB dongle$6626 mW+10 dBComfortable
iBasso DC03 ProUSB dongle$6939 mW+12 dBComfortable
DUNU DTC 480USB dongle$7026 mW+10 dBComfortable
EPZ TP35 ProUSB dongle$7045 mW+13 dBComfortable
Tanchjim SpaceUSB dongle$7050 mW+13 dBComfortable

The three ways a source goes wrong

Hiss. At 107.0 dB/V these are sensitive enough to reveal a source's own noise floor. The noisiest source in the database, the Schiit Mjolnir 3, would put its hiss at roughly 15 dB SPL in these headphones — clearly audible in quiet passages. Check your own source.

Output impedance. At 80Ω these want a source output impedance below 10.00Ω to satisfy the one-eighth rule; 25 of the 192 sources that publish one miss it. Check yours here.

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