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Violectric HPA V550 PRO
Powerful balanced headphone amplifier with 256-stage relay
The Violectric HPA V550 PRO is a high-end analog headphone amplifier with a perfect preamplifier and a wide range of functions. The HPA V550 PRO offers outstanding technical values, excellent sound and workmanship in the best manufacturing quality.
The pre-gain circuit allows the amplifier to be adapted to the requirements of the headphones being used. Even critical designs such as magnetostats can be easily operated via the balanced and the two unbalanced headphone connections. Up to three analog stereo sources can be connected via one XLR and two RCA connections. The HPA V550 PRO also offers one balanced and one unbalanced output. High-quality ALPS RK27 potentiometers are used for volume and balance control.
The volume control in the HPA V550 PRO is implemented using a relay circuit with 256 levels. An included remote control offers maximum ease of use.
Inputs & outputs
Inputs analog, stereo
-> 2x RCA unbalanced
-> 1x XLR female balanced
+++ Inputs switchable on front with button +++
Outputs headphones
-> 1x jack 6.3 mm, unbalanced
-> 1x XLR 4-pin, female, balanced
-> 1x Pentaconn 4.4 mm, balanced
Outputs analog, stereo
-> 1x RCA unbalanced
-> 1x XLR male balanced
+++ Outputs switchable on front with button (HEAD / MUTE / LINE) on rear with button (Line Pre / Post) +++
Relay Controlled Attenuator (RCA)
The volume of the Violectric HPA V550 PRO is controlled via a 256-stage reed relay circuit. This ensures the best sound and perfect channel balance over the entire control range.
The advantages of using “RCA” are
- no scratching, as there is no resistor track
- best channel balance thanks to the use of 1% and 0.1% resistors
- minimal crosstalk, as the channels are spatially separated
- control range (theoretically) greater than with a potentiometer
- no risk of additional “distortion” or “noise”, as only resistors are installed in the signal path
The relay-controlled attenuator is the best way to control the volume of an amplifier.
Balanced headphone outputs
When listening to music via loudspeakers, you are part of the auditorium. When listening through “normal” headphones, you take the place of the conductor. When listening with “balanced” headphones, you are part of the orchestra.
If headphones are operated symmetrically, the channel separation is increased even further. Balanced headphones usually have a 4-pin XLR connection or a Pentaconn plug. True balanced operation requires a great deal of effort in the form of four built-in power amplifiers.
PRE-GAIN
The headphone amplifier is positioned between the music source and the headphones. The source can be of varying power and the headphones of varying sensitivity. The Lake People PRE-GAIN serves to compensate for these differences and to optimize the headphone amplifier for every conceivable combination. This results in minimal noise, the lowest distortion factor and the best channel balance.
The PRE-GAIN adjustment is located on the rear of the Violectric HPA V340 and can be set individually in 7 stages (-18, -12, -6, 0, +6, +12, +18 dB)
Perfect headphone protection
Various circuits protect the headphones from unclear operating states, DC voltage, excessive operating temperature and overload:
Delayed ON, Instant OFF
Every headphone amplifier causes interference when it is switched on and off. This interference can damage the connected headphones. The headphones are connected to the amplifier with a delay via relays and the associated electronics and disconnected again immediately after switching off. In this way, the headphones themselves are protected from the device electronics as long as no clearly defined conditions are to be expected.
DC monitoring
The outputs are monitored for harmful DC voltage. As soon as a predefined value is exceeded, the headphones are switched off.
Overload monitoring
The power consumption is constantly measured during operation. If predefined parameters are exceeded, the headphones are switched off.
Remote control
Control the Violectric HPA V550 PRO remotely with its beautifully designed remote control milled from a solid piece of metal. Infrared gives you access to the most important functions of the device:
- Volume
- Mute
- Input selection (XLR / RCA1 / RCA2)
- Output selection (headphones / LineOut)
Violectric's unique technology
- Lowest noise - thanks to very low internal amplification. This means that the amplifier's own noise is inaudible.
- High output voltage - due to an internal 50 volt operating voltage. Therefore ideally suited for high-impedance headphones.
- High output power - thanks to powerful amplifiers that can deliver far more power than even the most demanding headphones require. Therefore ideally suited for headphones with low impedances and magnetostats.
- High damping factor - due to the lowest output impedance. Therefore ideally suited to drive even the most difficult headphones without interference. The advantage for an uncompromising frequency response.
Violectric - The brand for music lovers
- Violectric brings decades of expertise and the uncompromising quality standards of professional Lake People products to the world of hi-fi - with passion! Music lovers all over the world rave about the seamless integration into their systems: from a convenient and versatile input section to precisely adjustable gain control and digital interfaces with first-class converter technology at broadcast level - no wish remains unfulfilled here.
- The entire Violectric portfolio impresses with intuitive operability that is otherwise only known from professional audio technology. And there are no compromises when it comes to quality: Every single component is carefully selected to guarantee maximum sound fidelity.
- However, Violectric not only stands for outstanding technology, but also for timeless elegance. The products are integrated into an elegant, high-quality housing and fit perfectly into any sophisticated hi-fi setup. For audiophile perfectionists who don't want to compromise, the Niimbus series offers the ultimate - both visually and technically at the very highest level.
Features
- balanced inputs via gold-plated Neutrik XLR sockets
- unbalanced inputs via gold-plated RCA sockets
- PRE-GAIN: 7-stage internally adjustable gain
- Powerful balanced stereo amplifier (4 output stages)
- Compact and extremely robust aluminum housing
- Made in Germany
Dealers selling Violectric near you
Violectric’s HPA V550 PRO is a desktop, true-balanced headphone amplifier that stands out for its combination of near-silent operation and surgical control. Reviewers such as John Hoffman and Audiophilepure praise its low noise floor, the seven-step PRE‑GAIN options and the precise 256-step reed‑relay volume control. Sonically it delivers a natural, intimate midrange, authoritative, well-textured bass and an enveloping headphone soundstage that unlocked the Focal Stellia’s potential in listening tests. Dynamics and transient control are consistently highlighted, and the unit doubles as a capable preamplifier with balanced I/O. The chassis and mechanical design, including the silent relay attenuator, are built to a professional standard. Ideal for owners of high-performance, low-impedance headphones seeking reference-level quiet and fine-grained level control.
Pros
- Exceptionally low noise floor with a silent reed‑relay/stepped attenuator, yielding very quiet background performance.
- Highly precise level control via a 256-step reed‑relay volume control plus seven-position PRE‑GAIN, enabling optimal gain staging and minimal noise.
- Natural, intimate tonal balance with authoritative, well-textured bass and expansive headphone imaging that reveals detail and musical nuance.
- Robust, professional build and useful preamplifier functionality with balanced I/O — a versatile desktop component.
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Cons
- Preamplifier stage does not match the spatial refinement of the very highest-end dedicated preamps (e.g., Halcro DM8), so two-channel purists may prefer a separate top-tier preamp.
Sound Quality
90/100
Reviews report strong dynamic contrasts and natural transient behaviour: Positive Feedback notes an "intimate and graceful presentation of the dynamic contrasts" and powerful, breathing bass passages. The PRE-GAIN implementation also gives precise output control, supporting excellent headroom and liveliness.
Noise Floor
95/100
Multiple reviewers explicitly praise the extremely low noise floor: Audiophilepure and Positive Feedback state the PRE-GAIN stage ensures a very low / "lowest noise floor possible" and the stepped attenuator/relay arrangement is silent. That language and the ability to dial PRE-GAIN to reach minimal noise justify a reference-class noise-floor score.
Headphone Compatibility
89/100
The amplifier is a true-balanced transistor design "compatible with lower impedance loads" and offers seven PRE-GAIN settings (-18 to +18 dB), which reviewers used to achieve both low noise and usable drive levels. Front-panel balanced and multiple single-ended outputs plus true-balanced topology give broad compatibility across sensitive IEMs to more demanding headphones.
Build Quality
92/100
Build is repeatedly praised: solid, nicely finished chassis, pride of craftsmanship, and a high-quality 256-step reed-relay attenuator with gas-filled protection. Reviewers call the design impressive and note silent volume changes, indicating excellent mechanical and electrical construction.
Features Connectivity
90/100
Beyond the baseline amp, the V550 PRO provides true-balanced circuitry, balanced headphone output(s), PRE-GAIN selectable input attenuation, a 256-step volume control and multiple headphone outputs; it also functions as a preamplifier. Those extras (balanced I/O, multi-level PRE-GAIN, multiple outputs and preamp capability) push this unit well above the baseline feature set.
Value for Money
89/100
Reviewers describe the V550 PRO as a high-performance, well-built amplifier that deserves serious consideration (Audiophilepure) and call it an "excellent headphone amplifier" (Positive Feedback, which lists retail ~$2,799). The language indicates a justified premium: strong build and performance for its price in the high-end desktop segment.
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