This is a review and detailed measurements of the Violectric HPA V550 PRO headphone amplifier. It is was sent to me by their US distributor, Power Holdings. It costs 2,999.00EUR and US $3,399 as optioned in US.
This is one beefy, high quality execution making you feel like you are getting something for your money:
The large volume control feels nice and manages a stepped relay gain stage. Mechanically it is pretty silent. The unit comes with a remote control which adjusts the volume using its motorized mechanism. This is not needed for the headphone amp in desktop mode of course but there is an independent preamplifier with its gain control.
Speaking of gain, I am not a fan of dip switches in the back although they do provide a lot of flexibility:
There are a ton of configurations to play with here. I limited myself to XLR balanced input and XLR balanced outs.
There is a non-Pro version that doesn't have the stepped relay volume control.
Violectric HPA V550 Pro Measurements
I set the switches to all off which is 0 dB gain and adjusted the same using the volume control. Here is our dashboard of XLR input and XLR headphone out:
For some reason I expected worse performance so was pleasantly surprised with this. One channel is lagging due to elevated noise. I later traced this to the volume control. As is, performance is certainly excellent as far as distortion with a second harmonic well below audibility at -122 dB. SINAD though includes noise and there, we are left behind top of the class:
Here is our SNR:
I was surprised that even after setting the gain to -18 dB, at 50 mv, noise is fairly high:
So not a good fit for very sensitive IEMs.
Frequency response is wide and dead flat:
Most impressive aspect of this amplifier is the amount of power it can produce with high impedance headphones:
Power is super healthy for 32 ohm load as well:
Again, noise is a bit high but distortion is quite competitive.
Here is the performance across a range of loads:
Channel matching is excellent:
Violectric HPA 550V Pro Pre-amplifier Measurements
Here is a quick measurement with and without volume control active:
Notice how the elevated noise in the red channel went away with volume control bypassed.
Also, you have superb performance of 118 dB SINAD while producing 8 volts output. This will be a great match for a high-performance power amplifier with low gain. With modification of gain switches, you can get even higher voltages.
Violectric HPA 550V Pro Listening Tests
Let's not play around here. The HP 550V had no trouble driving both my Sennheiser HD650 and Drop Ether CX to maddening levels with superb fidelity and no hint of distortion. The only thing I did not like was that at the lowest volume settings, the were discontinuities in the signal as you changed the volume. Fortunately with these two headphones, I did not need to go down that low. And if I did, I could use negative gain to push the usable level higher.
Conclusions
From mechanical design, the 550V Pro stands alone. It comes in a wonderful enclosure that is solid, and controls that are a delight to use. Performance as far as noise is not quite competitive but distortion is vanishingly low. Most importantly, there is tons of power to drive any headphone you throw at this unit. So not quite perfect electrically but perfect when you combine it with the mechanical aspects and features such as pre-amplifier.
I am happy to recommend the Violectric HPA 550 Pro.
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As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
This is one beefy, high quality execution making you feel like you are getting something for your money:
The large volume control feels nice and manages a stepped relay gain stage. Mechanically it is pretty silent. The unit comes with a remote control which adjusts the volume using its motorized mechanism. This is not needed for the headphone amp in desktop mode of course but there is an independent preamplifier with its gain control.
Speaking of gain, I am not a fan of dip switches in the back although they do provide a lot of flexibility:
There are a ton of configurations to play with here. I limited myself to XLR balanced input and XLR balanced outs.
There is a non-Pro version that doesn't have the stepped relay volume control.
Violectric HPA V550 Pro Measurements
I set the switches to all off which is 0 dB gain and adjusted the same using the volume control. Here is our dashboard of XLR input and XLR headphone out:
For some reason I expected worse performance so was pleasantly surprised with this. One channel is lagging due to elevated noise. I later traced this to the volume control. As is, performance is certainly excellent as far as distortion with a second harmonic well below audibility at -122 dB. SINAD though includes noise and there, we are left behind top of the class:
Here is our SNR:
I was surprised that even after setting the gain to -18 dB, at 50 mv, noise is fairly high:
So not a good fit for very sensitive IEMs.
Frequency response is wide and dead flat:
Most impressive aspect of this amplifier is the amount of power it can produce with high impedance headphones:
Power is super healthy for 32 ohm load as well:
Again, noise is a bit high but distortion is quite competitive.
Here is the performance across a range of loads:
Channel matching is excellent:
Violectric HPA 550V Pro Pre-amplifier Measurements
Here is a quick measurement with and without volume control active:
Notice how the elevated noise in the red channel went away with volume control bypassed.
Also, you have superb performance of 118 dB SINAD while producing 8 volts output. This will be a great match for a high-performance power amplifier with low gain. With modification of gain switches, you can get even higher voltages.
Violectric HPA 550V Pro Listening Tests
Let's not play around here. The HP 550V had no trouble driving both my Sennheiser HD650 and Drop Ether CX to maddening levels with superb fidelity and no hint of distortion. The only thing I did not like was that at the lowest volume settings, the were discontinuities in the signal as you changed the volume. Fortunately with these two headphones, I did not need to go down that low. And if I did, I could use negative gain to push the usable level higher.
Conclusions
From mechanical design, the 550V Pro stands alone. It comes in a wonderful enclosure that is solid, and controls that are a delight to use. Performance as far as noise is not quite competitive but distortion is vanishingly low. Most importantly, there is tons of power to drive any headphone you throw at this unit. So not quite perfect electrically but perfect when you combine it with the mechanical aspects and features such as pre-amplifier.
I am happy to recommend the Violectric HPA 550 Pro.
-----------
As always, questions, comments, recommendations, etc. are welcome.
Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
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