The Beyerdynamic DJ 300 PRO X is 48Ω at 115.0 dB (no reference unit printed); the Beyerdynamic DT 770 Pro (250Ω) is 250Ω at 96.0 dB (no reference unit printed). This page covers what they ask of an amplifier, not how they sound.
The DT 770 Pro (250Ω) needs 19.0 dB more than the DJ 300 PRO X to reach the same loudness — 2.5 mW against 0.03 mW.
| Specification | DJ 300 PRO X | DT 770 Pro (250Ω) |
|---|---|---|
| Impedance | 48 Ω | 250 Ω |
| Sensitivity | 115.0 dB | 96.0 dB |
| Sensitivity (voltage) | 128.2 dB/V | 102.0 dB/V |
| Power for 100 dB | 0.03 mW | 2.5 mW |
| Voltage for 100 dB | 39 mV | 0.79 V |
| Current for 100 dB | 0.8 mA | 3.2 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 6.00 Ω | 31.25 Ω |
| Sources that reach 100 dB out of 280 | 280 | 277 |
One caution before reading the rows. Beyerdynamic DJ 300 PRO X and Beyerdynamic DT 770 Pro (250Ω) printed a decibel figure with no reference unit, so this page reads it as per milliwatt. If it is really per volt, each of them needs far more than the table says. Why the two readings differ by so much.
3 of the 280 sources have the power for the DJ 300 PRO X but not for the DT 770 Pro (250Ω) — Apple USB-C dongle (EU), Steinberg UR22C, Sony NW-A306.
18 sources are low enough in output impedance for the DT 770 Pro (250Ω) under the one-eighth rule but not for the DJ 300 PRO X (Zoom AMS-22, Arturia MiniFuse 2, Arturia MiniFuse 1, 15 more).
19 sources stay below the audible-hiss threshold with the DT 770 Pro (250Ω) but cross it with the DJ 300 PRO X (FiiO BTR11, FiiO K11 R2R, Lake People G103-S Mk II, 16 more).
277 of the 280 sources here reach 100 dB on both.
The DT 770 Pro (250Ω) is more demanding than 95% of the 567 non-electrostatic models in this database; the DJ 300 PRO X than 6%.
| dB SPL | DJ 300 PRO X power | DJ 300 PRO X voltage | DT 770 Pro (250Ω) power | DT 770 Pro (250Ω) voltage |
|---|---|---|---|---|
| 80 | 0.3 µW | 4 mV | 0.03 mW | 79 mV |
| 85 | 1.0 µW | 7 mV | 0.08 mW | 0.14 V |
| 90 | 3.2 µW | 12 mV | 0.25 mW | 0.25 V |
| 95 | 0.01 mW | 22 mV | 0.79 mW | 0.45 V |
| 100 | 0.03 mW | 39 mV | 2.5 mW | 0.79 V |
| 105 | 0.10 mW | 69 mV | 7.9 mW | 1.41 V |
| Source | Price | Headroom, DJ 300 PRO X | Headroom, DT 770 Pro (250Ω) | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 28.0 dB | 1.8 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 36.3 dB | 10.2 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 33.2 dB | 6.8 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 277 reach 100 dB on both. 53 of them also publish an output impedance low enough for both under the one-eighth rule and a noise figure that stays below the audible-hiss threshold with both.
The cheapest of the 53 is the JadeAudio JA11, at $20. It leaves 28.0 dB of headroom on the DJ 300 PRO X and 1.8 dB on the DT 770 Pro (250Ω), its output impedance is 0.5 Ω against a one-eighth limit of 6.00 Ω and 31.25 Ω, and its noise figure puts the hiss floor 7 dB and 33 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| DJ 300 PRO X | 5 - 35,000 Hz | not printed | not printed |
| DT 770 Pro (250Ω) | 5 - 35.000 Hz | not printed | not printed |
Beyerdynamic prints 5 - 35,000 Hz for the DJ 300 PRO X and 5 - 35.000 Hz for the DT 770 Pro (250Ω).
Neither range has a tolerance printed beside it, so a wider range on one sheet is not deeper bass or more treble.
Not a measurement; maker by maker.
Both have a page of their own. In full: Beyerdynamic DJ 300 PRO X and Beyerdynamic DT 770 Pro (250Ω). Each figure on this page is labelled on those pages with where it came from, including the ones Beyerdynamic never published — what that maker publishes, counted.