Audio Valve RKV HAA Edition

Amplifier Specifications

• OTL - transformer outless tube amplifier ( signal closed feedback loop in OTL concept )
• double mono construction
• Alps volume control ( or remote control as option )
• output: 2 pcs. 6,3 mm stereo / XLR combi jack and 4 pin Sennheiser jack for headphones
• input: 2 pairs of cinch and 1 pair XLR inputs
• tubes: actual 4 x 6F5P (ECL85) earlier time: (PCL 85 or 18GV8 )
• power output: each channel 8 watt on 220 ohms load per channel
• bandwide: 15 - 100 000 hz
• internal resistance: 0,3 ohms
• 2 x 8 watt / 200 ohms load
• distortion 0,002 % at 1 Watt-200 Ohm load
• max. output voltage 100V
• sens. 0dBm
• IC - OPA134 - AC/DC controlled - full autom. - controlled bias
• class - a / minimum load 35 ohms - maximum load 2000 ohms
• power consumption min. 60 watt
• size 370*270*140 mm (d.w.h.)
• weight 6kg
• Best ever remote control (A Volume down B volume up) *my contribution to the specification

Equipment used

Headphones

• Sennheiser HD800s
• ZMF Aeolus
• Audeze LCD-MX4

Amplifiers

• Drop THX AAA789
• Feliks Audio Euphoria

Dac

• Chord Qutest
• Grace SDAC Balanced

Source

• Mac mini running Audirvana

Playlist

1. Melanie De Biasio - Your Freedom is the End of Me
2. Hans Zimmer - Mountains
3. Gillian Welch - The Way it Goes
4. Florence & The Machine - Ship to Wreck
5. Dire Straits - Water of Love
6. Antonio Vivaldi - Winter Concerto in F minor
7. Tchaikovsky - Swan Lake, Swan Theme
8. Biig Piig - Roses and Gold
9. Amber Rubarth - Hold On
10. Billie Eilish - Everything I wanted
11. Metallica - Enter Sandman
12. Led Zeppelin - Ramble on
13. Beyonce - Daddy Lessons
14. Kenny Burrell - Chitlins Con Carne
15. Dave Brubeck - Take Five
16. Air - Talisman
17. Bombino - Iyat Na Hay
18. GoGo Penguin - Totem
19. Hans Theessink - St. James Infirmary

Review

If you are looking for a review that will describe graphs with frequency responses and measurements then I might not be your best bet. For me measurements is a tool to understand if the equipment is broken or get some high level information for pairing components. I prefer to describe how the equipment makes me feel and how it sounds to my ears, subjectively, compared to other equipment. This is the Audio Valve RKV Headphones Auditions Amsterdam version (HAA). HAA is a store in Amsterdam dedicated to headphones and associated equipment such as amplifiers, DACs etc. The special mention to HHA is due to the fact that this amplifier is only available through HAA and Stefan who is more of a host rather than just another salesman. Stefan played an instrumental role on the amplifier’s development and has a scope to be praised in an online ERA. You can walk in and try any headphone, amp, DAC you wish. The Audio Valve RKV HAA is an OTL version of the Luminare with some upgrades. I am not a technical person, so I will leave that with the designer.



I don’t review equipment on loan. I review gear I buy with my own money and for me it’s a hobby rather my main activity. The only reason I spend the time writing my thoughts is purely to share feelings and opinions/information on audio gear with other fellow audiophiles/music lovers.



So, where shall I begin? I’ve owned my fair share of headphone amplification. From solid state to valves, both have their merits and place within the audio world. I was after a valve amplifier for certain reasons. For me what valve amplifiers do well, compared to solid state, is “space”. This holographic presentation with a soundstage which has width, depth and hight. Also many good valve amplifiers excel on imaging and air. Therefore Imaging and soundstage was my aim without the drawbacks of valve amplification. To get it out of the way the RKV HAA excels on space and imaging. I was listening to Vivaldi’s 4 seasons and it was scary when the main violin start playing. It was precise, immediate with clear space and air around it but most importantly the tonality was right. I mean the violin didn’t sound like a viola.

This amplifier is not a “romantic” rolled off and warm amplifier. I would describe the sound signature as balanced across the frequency response with a slight (very slight) emphasis on the low end. This is a very transparent amplifier easily highlighting the differences between DACs and sources. There is body to the sound and that helps with compressed, poor recordings that I like such as albums by Oasis, Liam Gallagher and Florence & the Machine. This compressed type of music might come as clinical and flat through a solid state amplifier such as the THXAA789 in hand. With the Audio Valve you get the missing body/texture either on the warm ZMF Aeolus or the x-ray detailed Sennheiser HD800s. So, on that front the Audio Valve RKV HAA will made compressed music sound great and enjoyable instead of an annoyance.

For me this is important because I do like many poorly recorded albums and what's the point if I can't enjoy the music. Moreover, the Audio Valve RKV HAA has an effortless nature with power to spare. Remember that is an OTL design delivering voltage. To be honest I never exceeded 12 o’clock with any headphone in my collection. During audition I tried the amplifier with the Abyss AB-1266 TC and Hifiman Susvara. No problem driving these headphones at their full potential with ease, again with the volume pot at max 12 o’clock. The amplifier employs an attenuation type gain. That means you are basically reduce gain from the normal condition.



So, if power and control is your thing then you will not be disappointed. Mids have correct tonality and to put it simple vocals and instruments sound right. The most direct comparison for the mids is kind of Harbeth like. I have the Harbeth P3ESR-XD and the Audio Valve RKV HAA with the ZMF Aeolus gave me this texture on the mids.

The upper end is well extended and detailed without being harsh or unnatural. This is important to me because tone is my number one priority in sound quality. I've tried the upper mids and highs with the HD800S and I’ve never heard these headphones more complete. The top end is well extended but now we have body to the sound. I always thought that the HD800s are great on some areas but were always slightly boring sounding headphones, with an analytical nature lacking the enjoyment I was after. With a solid state amplifier the HD800s is flat and weightless. With the Feliks Euphoria it was muffled and congested but with the Audio Valve it was open and full body like a good Spanish Rioja wine instead of a clean and crisp Chardonnay (its all about taste). I was also curious to see how an OTL design will work with a low impedance planar magnetic. For that I brought the Audeze LCD-MX4 which is rated at 20 ohms. No problem whatsoever. The only slight hiss was at 13:00 o’clock and above which to be honest is pointless since at 12 o’clock you will be bleeding. Apparently, the RKV HAA In contrast to the standard RKV2, can drive higher currents even to low-resistance loads due to different tube equipment and a tuned OTL circuit design, which is 2 x 8 watts at 200 ohms. In principle, the RKV2 can't do that because it was designed for high-impedance headphones.

Compared to the TXHAAA789 there is no contest but both amps have their place. The THXAAA789 is more of a transparent tool for work rather than an equipment for enjoyment. It sounds clean enough but flat and 2D compared to the holographic image with the Audio Valve RKV HAA. From the other hand, compared to the Feliks Audio Euphoria, which is a more appropriate comparison, the amplifier is far more dynamic and transparent. The Feliks is a good valve amplifier but suffers the valve drawbacks. The low end is a bit lean and the tremble is rolled off in comparison. Compared to the Audio Valve it sounded muffled and congested with a much smaller soundstage. The Audio Valve RKV HAA is just a great amplifier no matter the topology. What I mean is that the Audio Valve does not have the drawbacks of a valve amplifier but all the benefits. So, we have an amplifier with space, body, sparkle and balanced sound that will give you goosebumps with power to spare for the hardest to drive headphones. The Audio Valve RKV HAA gave me the biggest smile ever, listening album after album and has been so far the greatest surprise in my audiophile journey. This is a keeper and will stay with me for the long ride.




Thanks for reading.

Leo

PS: for more technical info please refer to Audio Valve's website here and HAA's website here and @StefanHAA