Short answer: the Violectric HPA V550 PRO. It ranks #11 of 19 headphone amplifiers by measured performance, rated 4.6/5, at $3,599.99. The Benchmark HPA4 ranks #13, rated 4.0/5, at $3,499, $100.99 cheaper, a saving that is not big enough to make up the sound-quality gap.
The Violectric HPA V550 PRO is the better-sounding choice. Violectric rates it at 4,700 mW into 32 ohms and 1,450 mW into 300 ohms, enough to drive nearly any headphone, and Audio Science Review measured a SINAD of 111 dB, clean for nearly all listening. The tradeoff: The Topping A50 III rates higher and measured cleaner in Audio Science Review’s tests for a small fraction of the price.
Why pick the Benchmark HPA4: Audio Science Review measured a SINAD of 119 dB, so the amp is transparent. Watch for: Benchmark does not publish a power figure into 32 ohms, so its output into low impedance planar magnetic headphones is unconfirmed.
Buy the Violectric HPA V550 PRO. It is rated higher, and the $100.99 you would save on the Benchmark HPA4 does not close the gap.
Still deciding? The full Headphone Amps and DACs rankings cover every ranked option.
Specifications Side By Side
| Violectric HPA V550 PRO | Benchmark HPA4 | |
|---|---|---|
| Price | $3,599.99 | $3,499.00 |
| Ranked | #11 of 19 in Headphone Amplifiers | #13 of 19 in Headphone Amplifiers |
| Device Type | Headphone amp | Headphone amp |
| SINAD | 111 dB (measured by Audio Science Review) | 119 dB (measured by Audio Science Review) |
| Output Power (32 ohms) | 4,700 mW (manufacturer rated) | - |
| Output Power (300 ohms) | 1,450 mW (manufacturer rated) | 441 mW (calculated from manufacturer rated 11.5 Vrms into 300 ohms) |
| Headphone Outputs | 6.35 mm, 4-pin XLR balanced, 4.4 mm balanced | 6.35 mm, 4-pin XLR balanced |
| Balanced Output | Yes (4-pin XLR, 4.4 mm, XLR line out) | Yes (4-pin XLR headphone, XLR line out) |
| Inputs | 2 x RCA, XLR | 2 x XLR, 2 x RCA |
| Outputs | RCA, XLR | XLR, RCA |
| Volume Control | Hardware knob (256-step relay attenuator, remote) | Hardware knob (256-step relay attenuator, IR remote) |
| Dimensions | 11.4” x 3.1” x 9.8” (290 x 80 x 248 mm) | 8.7” x 3.9” x 8.3” (220 x 99 x 212 mm) |
| Weight | - | 7.9 lbs (3,600 g) |
Related Amp and DAC Comparisons
More top alternatives to Violectric HPA V550 PRO:
- Topping A90 Discrete vs Violectric HPA V550 PRO
- SMSL VMV P2 vs Violectric HPA V550 PRO
- Tom Christiansen Audio HPA-1 vs Violectric HPA V550 PRO
- Violectric HPA V550 PRO vs Soncoz SGA1
- Violectric HPA V550 PRO vs Chord Alto
Prices on this page were last checked October 11, 2026 at 4:59 PM UTC. Product prices and availability are accurate as of that date/time and are subject to change; the price and availability shown on Amazon at the time of purchase will apply to the purchase of this product.
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The Two Amps and DACs In Full
Violectric HPA V550 PRO: $3,599.99 Amazon eBay
Pros: Violectric rates it at 4,700 mW into 32 ohms and 1,450 mW into 300 ohms, enough to drive nearly any headphone, and Audio Science Review measured a SINAD of 111 dB, clean for nearly all listening. It offers 6.35 mm, 4-pin XLR and 4.4 mm balanced headphone outputs, RCA and XLR inputs and outputs, and a 256-step relay volume control with a remote.
Cons: The Topping A50 III rates higher and measured cleaner in Audio Science Review’s tests for a small fraction of the price. It is an analog amp only, so you still need a separate DAC.
Full Violectric HPA V550 PRO review and specifications →
| Balanced Output | Yes (4-pin XLR, 4.4 mm, XLR line out) |
|---|---|
| Device Type | Headphone amp |
| Dimensions | 11.4” x 3.1” x 9.8” (290 x 80 x 248 mm) |
| Headphone Outputs | 6.35 mm, 4-pin XLR balanced, 4.4 mm balanced |
| Inputs | 2 x RCA, XLR |
| Output Power (300 ohms) | 1,450 mW (manufacturer rated) |
| Output Power (32 ohms) | 4,700 mW (manufacturer rated) |
| Outputs | RCA, XLR |
| SINAD | 111 dB (measured by Audio Science Review) |
| Volume Control | Hardware knob (256-step relay attenuator, remote) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons
Benchmark HPA4: $3,499.00 Benchmark Media Systems eBay
Pros: Audio Science Review measured a SINAD of 119 dB, so the amp is transparent. It has a 4-pin XLR balanced headphone output, XLR and RCA line outputs for use as a preamp, and a 256 step relay volume control with IR remote. It is rated for 441 mW into 300 ohms, ample for high impedance headphones.
Cons: Benchmark does not publish a power figure into 32 ohms, so its output into low impedance planar magnetic headphones is unconfirmed. It costs far more than the JDS Labs Atom Amp 2, which rates higher with similar measured cleanliness. It has no built in DAC.
Full Benchmark HPA4 review and specifications →
| Balanced Output | Yes (4-pin XLR headphone, XLR line out) |
|---|---|
| Device Type | Headphone amp |
| Dimensions | 8.7” x 3.9” x 8.3” (220 x 99 x 212 mm) |
| Headphone Outputs | 6.35 mm, 4-pin XLR balanced |
| Inputs | 2 x XLR, 2 x RCA |
| Output Power (300 ohms) | 441 mW (calculated from manufacturer rated 11.5 Vrms into 300 ohms) |
| Outputs | XLR, RCA |
| SINAD | 119 dB (measured by Audio Science Review) |
| Volume Control | Hardware knob (256-step relay attenuator, IR remote) |
| Weight | 7.9 lbs (3,600 g) |
- Reviews, Comparisons and Sound Samples
- Head-to-Head Comparisons