This is a review and detailed measurements of the Rupert Neve RNHP headphone amplifier. It is on kind loan from a member. The RNHP costs US $499. That is beyond the price of some of the best headphone amplifiers so performance better be good.
The casework while DIY-like, has just enough touches to differentiate it:
I like the red knob and the graphics around it.
The LEDs are actually buttons you push to select one of three inputs:
Nice to see XLR inputs. The external power supply is a bit larger than typical phone charger and comes with sliding adapters for different mains connectors.
The chassis quite heavy and substantial, making you feel like you could drive on it and it would survive.
I did not like the long thumping and pumping sound when you power the unit on. Likely pushing DC into the headphones and not stabilizing quickly either.
Note that there is no gain switch so if you have channel imbalance with the volume control, you are stuck with it.
Headphone Amplifier Measurements
As usual, we start by pumping a super low distortion and noise 1 kHz sine wave into the amp at 4 volts and see what we get out:
Noise spectrum as seen in the FFT display is clean. SINAD which is the sum of distortion and noise comes in at 101 dB which is caused by 2nd harmonic. This kind of performance would have been very good a few years ago. But now? It is well below a dozen or more amplifiers:
Noise performance is good and less of an issue than distortion:
Frequency response is ruler flat which is excellent:
So any tonality difference you hear is most likely in your head especially when you consider its very low output impedance:
Power output into high impedance load of 300 ohm is good:
Not so good is when you lower the impedance of the load to 33 ohm:
Strange how distortion takes over at just a few milliwatts and stays constant. The worst part is limited output power of just 280 milliwatts. I expect well over 1000 milliwatts in this price category.
Channel balance is not great:
Headphone Listening Tests
I started using my Sennheiser HD-650 high impedance headphone. Performance here was excellent and I could reach quite high levels with no sign of distortion.
The situation changed drastically when I tried my Ether CX 25 ohm headphones. Above 12:00 o'clock on the volume control the sound would get bright (due to high distortion) and then proceed to drop out and glitch as you turned up the volume even more. For comparison, I went back to my Topping DX3 Pro and it has no such problem driving the same headphones. The DX3 Pro costs half as much and comes with a DAC included!
Conclusions
Unlike a lot of boutique audio products, the RNHP is not particularly broken. With 300 ohm load it actually sounds find and provides good objective performance. Low impedance headphones that are inefficient though give it a very hard time causing its performance to fall apart. At this price point, there is no excuse for this.
If you have it, and are using a high impedance headphone with it that is getting loud enough, then it is fine to keep it. But I would not purchase one new given half a dozen superb sounding and performing headphone amplifiers with more features and lower prices.
Needless to say, I can't recommend the RNHP.
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As always, questions, comments, recommendations, etc. are welcome.
Weather should be getting warmer soon which is good news. The bad news is the Panthers are demanding spring clothing. With so many of them, the cost of new outfits for all can be extremely high. So please help me out by donating money using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
The casework while DIY-like, has just enough touches to differentiate it:
I like the red knob and the graphics around it.
The LEDs are actually buttons you push to select one of three inputs:
Nice to see XLR inputs. The external power supply is a bit larger than typical phone charger and comes with sliding adapters for different mains connectors.
The chassis quite heavy and substantial, making you feel like you could drive on it and it would survive.
I did not like the long thumping and pumping sound when you power the unit on. Likely pushing DC into the headphones and not stabilizing quickly either.
Note that there is no gain switch so if you have channel imbalance with the volume control, you are stuck with it.
Headphone Amplifier Measurements
As usual, we start by pumping a super low distortion and noise 1 kHz sine wave into the amp at 4 volts and see what we get out:
Noise spectrum as seen in the FFT display is clean. SINAD which is the sum of distortion and noise comes in at 101 dB which is caused by 2nd harmonic. This kind of performance would have been very good a few years ago. But now? It is well below a dozen or more amplifiers:
Noise performance is good and less of an issue than distortion:
Frequency response is ruler flat which is excellent:
So any tonality difference you hear is most likely in your head especially when you consider its very low output impedance:
Power output into high impedance load of 300 ohm is good:
Not so good is when you lower the impedance of the load to 33 ohm:
Strange how distortion takes over at just a few milliwatts and stays constant. The worst part is limited output power of just 280 milliwatts. I expect well over 1000 milliwatts in this price category.
Channel balance is not great:
Headphone Listening Tests
I started using my Sennheiser HD-650 high impedance headphone. Performance here was excellent and I could reach quite high levels with no sign of distortion.
The situation changed drastically when I tried my Ether CX 25 ohm headphones. Above 12:00 o'clock on the volume control the sound would get bright (due to high distortion) and then proceed to drop out and glitch as you turned up the volume even more. For comparison, I went back to my Topping DX3 Pro and it has no such problem driving the same headphones. The DX3 Pro costs half as much and comes with a DAC included!
Conclusions
Unlike a lot of boutique audio products, the RNHP is not particularly broken. With 300 ohm load it actually sounds find and provides good objective performance. Low impedance headphones that are inefficient though give it a very hard time causing its performance to fall apart. At this price point, there is no excuse for this.
If you have it, and are using a high impedance headphone with it that is getting loud enough, then it is fine to keep it. But I would not purchase one new given half a dozen superb sounding and performing headphone amplifiers with more features and lower prices.
Needless to say, I can't recommend the RNHP.
------------
As always, questions, comments, recommendations, etc. are welcome.
Weather should be getting warmer soon which is good news. The bad news is the Panthers are demanding spring clothing. With so many of them, the cost of new outfits for all can be extremely high. So please help me out by donating money using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
