Both are desktop amplifiers, $3499 against $3600. This page puts them side by side on the only three things a maker can be held to — power, output impedance and noise — and then asks the question that actually matters: which headphones do they treat differently?
On raw power they are level: each reaches 100 dB on 567 of the 567 non-electrostatic models here.
| Specification | Benchmark HPA4 | Violectric V550 Pro |
|---|---|---|
| Power into 32Ω | 3.4 W | 4.7 W |
| Power into 150Ω | 829 mW | 2.9 W |
| Power into 300Ω | 440 mW | 1.4 W |
| Power into 600Ω | 220 mW | 740 mW |
| Output impedance | <0.1 Ω | 0.15 Ω |
| Output noise | 2.45 µV | 5.48 µV |
| Price | $3499 | $3600 |
| Headphones it reaches 100 dB on out of 567 | 567 | 567 |
A figure marked not published is missing from the maker’s own material, which is not the same as being good or bad. Where one of these two publishes a number and the other does not, the comparison on that axis cannot be made at all — and saying so is more useful than guessing.
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.
65 headphones stay below the audible-hiss threshold on the Benchmark HPA4 but cross it on the Violectric V550 Pro (64 Audio Nio, 64 Audio U12t, 64 Audio U18s, 62 more).
567 of the 567 models here reach 100 dB on both. That is a power count and nothing more; whether either source suits a given headphone also depends on the two lines above.
Each has a page of its own with every power figure traced to what the maker published and a full headphone list: Benchmark HPA4 and Violectric V550 Pro. Or put either against your own headphones in the source comparison tool.