Auva EQ

This review first appeared in October 2024 on fairaudio.de. By request of the manufacturer and permission of the author, it is hereby syndicated from the German original to reach a broader English audience. Ed.

Reviewer: Ralph Werner
Analogue sources: Drive: SME Model 15 Tonearm: SME 309 Pickup: MC: Denon DL-103R, Dynavector DV-20X2 H, Transrotor Figaro; MM: Shelter 201 Other: Flux-HiFi (needle cleaner), VPI HW-16.5 (record washer)
Digital sources: D/A converter: Rockna Wavelight+ Music server: Antipodes K22 G4 Other: Pink Faun LAN Isolator
Preamplifiers: Electrocompaniet EC 4.8 MKII, Pass XP-12 Phono : BMC Audio MCCI Signature ULN
Power amplifiers: Electrocompaniet AW 800 M, Pass X250.8 (stereo)
Speakers: Acapella High BassoNobile MK2
Headphones: Audeze LCD-2, Beyerdynamic DT-990, Sennheiser HD 800 S, Sony MDR-1000X, Teufel Supreme In
All-In-One: Ruark Audio R4
Cables: Speaker cable: Dyrholm Audio Phoenix, fis Audio Studioline NF cable: Dyrholm Audio Phoenix XLR, Boaacoustic Blueberry Signal.xlr, fis Audio Livetime (Cinch), Vovox and others Digital cable: Audioquest Cinnamon (Toslink), Audioquest Vodka 48 (HDMI/I2S), Boaacoustic Silver Digital Xeno (USB), fis Audio Magic (LAN cable), Wireworld Series 7 Starlight Gold (S/PDIF coaxial) Power cable: fis Audio Blackmagic, fis Audio Studioline
Power strip: fis Audio Blackmagic
Rack: Creaktiv Trend 3
Listening room: 40m², 2.45 m ceiling
Review component retail: €175/3

Some start young. Theo Stack, owner and developer of Stack Audio, is only in his early thirties yet his company already has form. Headquartered in the picturesque southern county of England's Devon, he’s been active since 2013 and developed very different products across the intervening eleven years. The first was a network player which didn't make it to market due to lack of Roon compatibility. Stack then took a hard left turn into analogue and concentrated on upgrades for Linn LP12 owners who wanted to tune with resonance-optimised plinths and sub chassis, arm boards and the like. According to Theo, they learned a lot about vibrations and their harmful influence on the sound – valuable knowledge that incorporates into the British company's current main product, the Auva speaker and component isolators. Their aim is to "remove masking vibrations and leave only the pure undistorted music."

Set of four Auva EQ. The labeled side faces the component to be decoupled.

Consequently they are currently developing further mechanical tuning products for non-Linn vinyl playback. With the SmoothLAN, Stack Audio also have a completely different helper in their portfolio and continue researching this sector. But that's not what we're about today but their device isolators Auva EQ. That's short for Audio Vibration Absorber; Equipment Isolator. In plain English, footers as the type of extra feet we put underneath components because we don't think their own soles optimal for sound. There are a few such tuning devices to market and like for most it is recommended that we connect the Auva EQ directly to the base plate of our device and not its stock feet. There's good reason. Basically there are two principles by which the Auva EQ aim to minimize resonances and their microphonic effect. On the one hand it is about the dissipation or absorption of vibrations that enter from our component like its built-in transformer. Auva's aluminium housing absorbs such vibrations and converts them into heat through a particle-filled inner chamber. To dissipate said vibrations as effectively as possible, a hard metal-to-metal contact with as few intermediate layers as possible is best. The particles are stainless steel shot of different grades intended to efficiently convert input kinetic energy to heat via friction. Stack Audio calls this particle impact dampening. The Auva speaker feet use several chambers for this which thanks to different shot fill are optimized for different frequency ranges. Theo Stack already applied for a patent on this.

On the other hand and in contrast to loudspeakers which should stand as rigidly as possible, electronic components benefit significantly from being decoupled from the ground. External vibrations shouldn't enter the device. Hence the second operating principle of the Auva EQ is a custom absorber of a height-adjustable screwed-on silicone base available in three different hardness values depending on the weight we intend to support. From softest to hardest, the load limits are 4, 10 and 15kg per foot. Divide the weight of your kit by three or four et voilà, you'll know whether to order the Auva EQ CSA-1, 2 or 3. All cost the same so a set of three gets €175, four cost €230 and a single €63 regardless of load capacity. Shipping is included and direct sales are expedited through a Dutch warehouse to avoid the post-Brexit Blues of VAT. There's even a 30-day return policy. Nice!

Of course results depends on our respective component and support surface. So I tried the Auva EQ under my preamplifier, power amplifier, phono stage and DAC, sometimes with and sometimes without an additional base on the rack. First finding: the sonic change stayed put but the delta differed. So what didn't happen? Dynamically, hardly anything alters. I'd say that percussive impulses place more precisely and cleanly with the footers as noticed on "People" by Micah P. Hinson from the LP I lie to you. But there's really no extra oomph to seem more powerful or massive, just more precise localization. Another thing which barely changed was tonality. If you look for a tool that shifts your system balance along the brighter => milder => more sonorous spectrum, you can largely forget about it. I personally think that's a good thing. Do insure proper coupling though. During one quick A/B I accidentally parked on a base-plate screw of the Electrocompaniet preamp without noticing. I was pretty surprised when it had a significant effect on the bass which came across as weaker. It was interesting what a difference that made.