The Grado Signature HP100 SE is 38Ω at 117.0 dB/mW; the Grado SR225x is 38Ω at 98.0 dB/mW. This page covers what they ask of an amplifier, not how they sound.
The SR225x needs 19.0 dB more than the Signature HP100 SE to reach the same loudness — 1.6 mW against 0.02 mW.
| Specification | Signature HP100 SE | SR225x |
|---|---|---|
| Impedance | 38 Ω | 38 Ω |
| Sensitivity | 117.0 dB/mW | 98.0 dB/mW |
| Sensitivity (voltage) | 131.2 dB/V | 112.2 dB/V |
| Power for 100 dB | 0.02 mW | 1.6 mW |
| Voltage for 100 dB | 28 mV | 0.25 V |
| Current for 100 dB | 0.7 mA | 6.5 mA |
| Highest source impedance that leaves them alone (one-eighth rule) | 4.75 Ω | 4.75 Ω |
| Sources that reach 100 dB out of 280 | 280 | 280 |
Every source in the database that drives one of them drives the other. On power, the choice between these two changes nothing about what amplifier you need.
31 sources stay below the audible-hiss threshold with the SR225x but cross it with the Signature HP100 SE (Kiwi Ears Allegro Mini, FiiO BTR11, Fosi Audio SK02, 28 more).
280 of the 280 sources here reach 100 dB on both.
The SR225x is more demanding than 66% of the 567 non-electrostatic models in this database; the Signature HP100 SE than 2%.
| dB SPL | Signature HP100 SE power | Signature HP100 SE voltage | SR225x power | SR225x voltage |
|---|---|---|---|---|
| 80 | 0.2 µW | 3 mV | 0.02 mW | 25 mV |
| 85 | 0.6 µW | 5 mV | 0.05 mW | 44 mV |
| 90 | 2.0 µW | 9 mV | 0.16 mW | 78 mV |
| 95 | 6.3 µW | 15 mV | 0.50 mW | 0.14 V |
| 100 | 0.02 mW | 28 mV | 1.6 mW | 0.25 V |
| 105 | 0.06 mW | 49 mV | 5.0 mW | 0.44 V |
| Source | Price | Headroom, Signature HP100 SE | Headroom, SR225x | Output impedance | Noise |
|---|---|---|---|---|---|
| JadeAudio JA11 | $20 | 31.0 dB | 12.0 dB | 0.5 Ω | 1.7 µV |
| FiiO KA11 | $29 | 39.3 dB | 20.3 dB | 0.7 Ω | 1.7 µV |
| FiiO BTR13 | $59 | 36.2 dB | 17.2 dB | 0.6 Ω | 1.0 µV |
Of the 280 sources here, 280 reach 100 dB on both. 42 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 42 is the JadeAudio JA11, at $20. It leaves 31.0 dB of headroom on the Signature HP100 SE and 12.0 dB on the SR225x, its output impedance is 0.5 Ω against a one-eighth limit of 4.75 Ω for both, and its noise figure puts the hiss floor 4 dB and 23 dB below the 20 dB SPL this site treats as the point where a quiet room stops hiding it.
| Model | As printed | Tolerance | Standard |
|---|---|---|---|
| Signature HP100 SE | 3.5 Hz – 51.5 kHz | not printed | not printed |
| SR225x | 20-22kHz | not printed | not printed |
Grado prints 3.5 Hz – 51.5 kHz for the Signature HP100 SE and 20-22kHz for the SR225x.
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: Grado Signature HP100 SE and Grado SR225x. Every figure on this page comes from what Grado published, or is derived from it — what that maker publishes, counted.