Short answer
Both are portable players, $800 against $949.
The iBasso DX260 reaches 100 dB on 566 of the 567 models here, the Astell&Kern SR35 on 565.
| Specification | Astell&Kern SR35 | iBasso DX260 |
|---|---|---|
| Power into 32Ω | 300 mW | 262 mW |
| Power into 150Ω | 64 mW | 56 mW |
| Power into 300Ω | 32 mW | 28 mW |
| Power into 600Ω | 16 mW | 14 mW |
| Output impedance | 1.1 Ω | 0.6 Ω |
| Output noise | 4 µV unverified | not published |
| Price | $800 | $949 |
| Headphones it reaches 100 dB on out of 567 | 565 | 566 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | Astell&Kern SR35 | iBasso DX260 |
|---|---|---|
| Socket | 4.4mm and 2.5mm | 4.4mm |
| Power into 32Ω | 1.1 W derived | 1.0 W |
| Power into 300Ω | 120 mW derived | 108 mW derived |
| Output impedance | 2.7 Ω | 1.1 Ω |
| Output noise | not published | not published |
| Headphones it reaches 100 dB on out of 567 | 567 | 566 |
Through the balanced sockets the Astell&Kern SR35 reaches 100 dB on 567 of the 567 models here and the iBasso DX260 on 566. Derived figures are worked out from the loads the maker did publish.
| Load | Astell&Kern SR35 | iBasso DX260 |
|---|---|---|
| 32 Ω | Upper bound | Derived |
| 150 Ω | Upper bound | Derived |
| 300 Ω | Upper bound | Derived |
| 600 Ω | Upper bound | Derived |
Neither column is a power rating, and the two are not even weak in the same way. The Astell&Kern SR35 figures are ceilings worked out from a maximum output voltage, on the assumption that the amplifier holds it into the load. The iBasso DX260 figures are worked out from figures its maker did publish — power at other loads, or the voltage printed beside it. The second method understates; the first flatters. That is the wrong way round for reading the table straight across, so a gap in favour of the Astell&Kern SR35 is the one to doubt.
1 headphone reaches 100 dB on the iBasso DX260 but not on the Astell&Kern SR35 — Moondrop PARA.
27 headphones are left alone by the iBasso DX260 under the one-eighth rule but coloured by the Astell&Kern SR35 (64 Audio Nio, 64 Audio U18s, 64 Audio Volur, 24 more).
565 of the 567 models here reach 100 dB on both.
Headroom is at a 100 dB SPL peak.
The widest gap on the list is the Campfire Audio Andromeda 2020: iBasso DX260 has +19 dB of headroom there against +13 dB. 5 dB is about 3.5 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Astell&Kern SR35 and iBasso DX260 because neither maker publishes no output noise figure.
| Headphone | Impedance | Needs | Astell&Kern SR35 headroom | iBasso DX260 headroom | Astell&Kern SR35 hiss | iBasso DX260 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +33 dB | +39 dB | not published | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +13 dB | +19 dB | not published | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +22 dB | +22 dB | not published | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +18 dB | +17 dB | not published | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +15 dB | +16 dB | not published | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +11 dB | +11 dB | not published | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +7 dB | +6 dB | not published | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +5 dB | +4 dB | not published | not published |
The iBasso DX260 costs $149 more than the Astell&Kern SR35. Out of the 567 models here, that difference buys 1 more model driven to 100 dB and 27 more models left alone under the one-eighth rule.
Nothing runs the other way: there is no axis here on which the cheaper of the two does better.
Only published figures count here; blank axes are counted separately.
Each in full: Astell&Kern SR35 and iBasso DX260.