Short answer
Both are desktop amplifiers, $929 against $699.
The Gustard H20 reaches 100 dB on 567 of the 567 models here, the Rupert Neve RNHP on 566.
| Specification | Gustard H20 | Rupert Neve RNHP |
|---|---|---|
| Power into 32Ω | 12.0 W | 262 mW |
| Power into 150Ω | 2.7 W | 175 mW |
| Power into 300Ω | 1.3 W | 88 mW |
| Power into 600Ω | 670 mW | 44 mW |
| Output impedance | not published | 0.08 Ω |
| Output noise | not published | 8.03 µV |
| Price | $929 | $699 |
| Headphones it reaches 100 dB on out of 567 | 567 | 566 |
Not published means the maker leaves it out, so that axis cannot be compared.
| Load | Gustard H20 | Rupert Neve RNHP |
|---|---|---|
| 32 Ω | Published | Derived |
| 150 Ω | Published | Published |
| 300 Ω | Published | Derived |
| 600 Ω | Published | Derived |
Both makers publish a power rating. Gustard H20 publishes at 32 Ω, at 150 Ω, at 300 Ω and at 600 Ω; Rupert Neve RNHP at 150 Ω. The other rows are worked out from those.
So the two columns are not equally firm row by row: at 32 Ω, at 300 Ω and at 600 Ω only the Gustard H20 figure is the maker’s own. On those rows the derived number is the one to doubt first.
1 headphone reaches 100 dB on the Gustard H20 but not on the Rupert Neve RNHP — Symphonium Titan.
566 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 HiFiMAN HE400se: Gustard H20 has +31 dB of headroom there against +15 dB. 16 dB is about 38 times the power, which matters for peaks rather than for how loud the music sits.
The hiss columns are empty for Gustard H20 because that maker publishes no output noise figure.
| Headphone | Impedance | Needs | Gustard H20 headroom | Rupert Neve RNHP headroom | Gustard H20 hiss | Rupert Neve RNHP hiss |
|---|---|---|---|---|---|---|
| Shure SE846 | 9 Ω | 0.04 mW | +49 dB | +35 dB | not published | 33 dB |
| Campfire Audio Andromeda 2020 | 9 Ω | 4.0 mW | +29 dB | +15 dB | not published | 13 dB |
| Audeze LCD-2 Classic | 70 Ω | 0.79 mW | +38 dB | +25 dB | not published | 11 dB |
| Beyerdynamic DT 1990 Pro (250Ω) | 250 Ω | 0.63 mW | +34 dB | +22 dB | not published | 6 dB |
| HiFiMAN HE400se | 25 Ω | 7.9 mW | +31 dB | +15 dB | not published | 5 dB |
| Audio-Technica ATH-R70X | 470 Ω | 1.6 mW | +27 dB | +15 dB | not published | -1 dB |
| Sennheiser HD 600 | 300 Ω | 6.6 mW | +23 dB | +11 dB | not published | -5 dB |
| HiFiMAN Susvara | 60 Ω | 50 mW | +21 dB | +7 dB | not published | -7 dB |
The Gustard H20 costs $230 more than the Rupert Neve RNHP. 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: Gustard H20 and Rupert Neve RNHP.