Short answer
Both are desktop DAC/amps, both at $449.
On raw power they are level: each reaches 100 dB on 567 of the 567 non-electrostatic models here.
| Specification | JDS Labs Element III MK2 | Topping DX5 |
|---|---|---|
| Power into 32Ω | 2.3 W | 1.8 W |
| Power into 150Ω | 584 mW | 433 mW |
| Power into 300Ω | 292 mW | 250 mW |
| Power into 600Ω | 146 mW | 125 mW |
| Output impedance | 0.7 Ω | 0.1 Ω |
| Output noise | 2.51 µV | not published |
| Price | $449 | $449 |
| Headphones it reaches 100 dB on out of 567 | 567 | 567 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | JDS Labs Element III MK2 | Topping DX5 |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Published | Derived |
| 300 Ω | Derived | Published |
| 600 Ω | Published | Derived |
Both makers publish a power rating. JDS Labs Element III MK2 publishes at 32 Ω, at 150 Ω and at 600 Ω; Topping DX5 at 32 Ω and at 300 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 150 Ω and at 600 Ω only the JDS Labs Element III MK2 figure is the maker’s own and at 300 Ω only the Topping DX5 figure is the maker’s own. On those rows the derived number is the one to doubt first.
On power they are interchangeable across this whole database: there is no headphone here that one reaches 100 dB on and the other does not.
4 headphones are left alone by the Topping DX5 under the one-eighth rule but coloured by the JDS Labs Element III MK2 (Campfire Audio Chimera, Moondrop Armature Art 12, Softears Volume, 1 more).
567 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 Audeze LCD-2 Classic: JDS Labs Element III MK2 has +31 dB of headroom there against +30 dB. 1 dB is about 1.3 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Topping DX5 because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | JDS Labs Element III MK2 headroom | Topping DX5 headroom | JDS Labs Element III MK2 hiss | Topping DX5 hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +42 dB | +41 dB | 22 dB | not published |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +22 dB | +21 dB | 2 dB | not published |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +31 dB | +30 dB | 1 dB | not published |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +27 dB | +27 dB | -4 dB | not published |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +24 dB | +22 dB | -5 dB | not published |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +21 dB | +20 dB | -11 dB | not published |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +16 dB | +16 dB | -15 dB | not published |
| HiFiMAN Susvara | 60 Ω | 50 mW | +14 dB | +13 dB | -17 dB | not published |
These two cost the same, $449, so price settles nothing. Out of the 567 models here, the Topping DX5 leaves 4 models alone under the one-eighth rule — and on the other side there is no such advantage at all.
Only published figures count here; blank axes are counted separately.
Each in full: JDS Labs Element III MK2 and Topping DX5.