Short answer
Both are dongles, $70 against $69.
The EPZ TP35 Pro reaches 100 dB on 561 of the 567 models here, the iBasso DC03 Pro on 560.
| Specification | EPZ TP35 Pro | iBasso DC03 Pro |
|---|---|---|
| Power into 32Ω | 112 mW | 98 mW |
| Power into 150Ω | 24 mW | 21 mW |
| Power into 300Ω | 12 mW | 10 mW |
| Power into 600Ω | 6.0 mW | 5.2 mW |
| Output impedance | not published | 0.12 Ω |
| Output noise | not published | 0.9 µV |
| Price | $70 | $69 |
| Headphones it reaches 100 dB on out of 567 | 561 | 560 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Balanced | EPZ TP35 Pro | iBasso DC03 Pro |
|---|---|---|
| Socket | 4.4mm | no separate rating |
| Power into 32Ω | 262 mW | — |
| Power into 300Ω | 28 mW derived | — |
| Output impedance | not published | — |
| Output noise | not published | — |
| Headphones it reaches 100 dB on out of 567 | 565 | — |
Only the EPZ TP35 Pro has a separate balanced rating from its maker; through it, it reaches 100 dB on 565 of the 567 models here. The iBasso DC03 Pro may still have a balanced socket — its spec sheet simply gives no figure for one, so there is nothing to put beside it. Derived figures are worked out from the loads the maker did publish.
| Load | EPZ TP35 Pro | iBasso DC03 Pro |
|---|---|---|
| 32 Ω | Published | Published |
| 150 Ω | Derived | Derived |
| 300 Ω | Derived | Derived |
| 600 Ω | Derived | Derived |
Both makers publish a power rating. EPZ TP35 Pro publishes at 32 Ω; iBasso DC03 Pro at 32 Ω. The other rows are worked out from those.
The two publish at the same loads, which is the one case where the rows of this table can be read straight across.
1 headphone reaches 100 dB on the EPZ TP35 Pro but not on the iBasso DC03 Pro — Moondrop PARA 2.
560 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 Audio-Technica ATH-R70X: EPZ TP35 Pro has +7 dB of headroom there against +6 dB. 1 dB is about 1.1 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for EPZ TP35 Pro because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | EPZ TP35 Pro headroom | iBasso DC03 Pro headroom | EPZ TP35 Pro hiss | iBasso DC03 Pro hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +29 dB | +28 dB | not published | 14 dB |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +9 dB | +8 dB | not published | -6 dB |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +18 dB | +18 dB | not published | -8 dB |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +14 dB | +13 dB | not published | -13 dB |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +10 dB | +10 dB | not published | -14 dB |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +7 dB | +6 dB | not published | -20 dB |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +3 dB | +2 dB | not published | -24 dB |
| HiFiMAN Susvara | 60 Ω | 50 mW | +1 dB | +0 dB | not published | -26 dB |
The EPZ TP35 Pro costs $1 more than the iBasso DC03 Pro. Out of the 567 models here, that difference buys 1 more model driven to 100 dB.
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: EPZ TP35 Pro and iBasso DC03 Pro.