Linux · Ground-up codec & playback

Putting the soul
back into rock 'n' roll.

The warmth, the harmonics, the feel of the analogue era — brought back with modern audio playback technology. Not nostalgia as a filter: a ground-up codec and playback engine that can stay honest and exclusive to your DAC, then open the door to living valve colour when you want the room to bloom.

RenniLink Valve King is not a skin on stock libraries. Decode, exclusive path, physics-led valves, and Glorious Lossy — built as one instrument for music that still feels played, not merely decoded.

Custom codec & playback engine Exclusive DAC path Physics-led valve engine £79.99 lifetime · 1 PC
Linux only · public trial download · £79.99 lifetime (1 PC, locks to that machine). Windows products: RenniLink home · AlcoMaster suite in development.

Analogue soul. Modern discipline.

Putting the soul back into rock ’n’ roll means more than a warm EQ preset. It means the era of analogue — harmonic bloom, body, and presence that made records feel alive — delivered through modern playback: exclusive device paths, honest path reporting, native rates when you want purity, and engines that know when the source is a master and when it is compressed.

The valve path is a physics-led engine, not a sat plug-in with a “tube” label. Packages are shaped from live measurements and measured amplifier behaviour — how real stages behave on the bench and in the room under quiet drive and under load — then closed into a real-time model that tracks level the way glass and iron do.

That measured behaviour informs the full signal path the ear cares about: valve working points and non-linear plate transfer; output-transformer character (bandwidth, damping feel, SE bloom vs tight push-pull control); power-supply manners (soft sag under demand versus stiff rails that hold the floor); feedback and topology (open single-ended colour, ultra-linear / push-pull grip, high-damping quietness, dual-mono width and centre); and load interaction so the amp does not sound the same into every imaginary 8 Ω resistor. Frequency balance is not a fixed “warm” shelf — bass weight, mid density, presence, and treble air follow the measured order of the class, so body and extension stay musical rather than smeared.

Inside the tube science: signal meets a curved transfer function. At small grids the stage stays cleaner; as drive rises, even-order harmonics (H2 silk that thickens vocals and guitars) appear first, then controlled odd-order content when the bottle is pushed — the same progression you hear when real valves work hard. The engine tracks that with music level: soft verses keep air and space; peaks take density, presence, and harmonic bloom instead of a digital hard limit. Soundstage cues (width, depth, centre focus) stay tied to topology so packages feel different — not “one preset louder.” When valves are off, the entire physics stack steps aside and the pure exclusive path returns.

Warmth that moves with the music

Real glass and iron never added a flat “warm” shelf. Valve colour here is physics-led — harmonics and tonality that shift with drive and level, so soft verses stay open and peaks take character instead of digital clamp.

Harmonics, not hash

The analogue era was rich in even-order silk and controlled grit when the amp worked hard. Valve King packages aim for that harmonic family character — body and air without sand, edge without hash — topology-class models, not a one-knob saturation toy.

Modern path, analogue option

Exclusive Direct and Pure keep the bit-honest route to your converter when integrity matters. Engage valves when you want the room to bloom. Turn them off and the pure path returns — modern discipline underneath, analogue soul on demand.

Built to feel music again

From jazz to the blues, through pop, rock, soul, and whatever sits on your shelf tonight — Valve King is built so listening feels warm and human again, not cold and decoded.

That is the promise of a modern-day analogue: exclusive paths and honest playback when purity matters; living harmonics and valve colour when you want body, air, and emotion — the presence that made records feel played in a room. Not a throwback for its own sake. A new-era analogue for digital libraries: the soul of the era of glass and iron, delivered with today’s converters, formats, and discipline.

From FLAC masters to everyday MP3 and radio: exclusive output when the kit allows, Glorious Lossy when the file is compressed, valve packages when you want that played-in-a-room feeling without leaving digital.

The player in use

Main player, song info, Audio Engine, song list, and radio. Click a screen for a larger view.

A valve engine built from the ground up

Purpose-built around how real glass and iron behave — not a plugin rack with a “tube” knob.

Physics-led

Reference-informed colour

  • Harmonics that move with music — not a fixed warmth shelf
  • Topology character — single-ended bloom, push-pull control, high-damping manners
  • Honest when off — turn valves off and the pure path returns
Trademark note

Topology class only

Amp packages are original topology-class models for listening, based on public datasheets and published circuit character. Not affiliated with, endorsed by, or clones of any named manufacturer.

Upsampling is not the best way to help the sonics

Many players and “hi-res” modes sell sample-rate inflation as an upgrade: stretch a 44.1 kHz file to 96 or 192 kHz and call it better. Mathematically, that is interpolation — new sample points estimated between the old ones — not new musical information. Valve King’s lossless path and Glorious Lossy are built on a different idea: keep masters honest at their true rate, and repair the real damage of compression where it lives.

01

What upsampling actually does

A digital audio file is a sequence of samples at a fixed rate. The highest frequency that sequence can represent is half that rate (the Nyquist limit) — about 22 kHz for CD-rate PCM. Upsampling (sample-rate conversion upward) inserts extra samples through a reconstruction / interpolation filter, then re-samples the continuous-looking waveform at a higher clock. The spectrum below the original Nyquist can be preserved with a high-quality converter; everything above the original bandwidth is either empty, filter stop-band leftovers, or imaging/ringing artefacts from the converter — not recovered studio detail.

  • No free bandwidth — a 320 kbps MP3 that already cut off near 16–20 kHz does not grow real content to 48 kHz just because the player clock runs faster
  • Filter trade-offs — linear-phase sinc-style SRC can ring before and after transients; minimum-phase designs reduce pre-ringing but still colour timing; neither invents missing MDCT coefficients
  • Another transform on the path — every forced SRC is an extra non-linear risk (quantisation, intermediate float, phase/time smear) between decoder and DAC
  • DAC already oversamples — modern converters run their own carefully designed oversampling and reconstruction filters; host-side “always 192 kHz” often just fights that chain or the OS soft mixer

Upsampling can be a legitimate engineering tool (match a fixed device rate, feed a specific DSP block, avoid a bad OS resampler). It is a weak lever for sonics: it does not put back what a perceptual codec threw away, and it can smear the attacks rock ’n’ roll lives on.

02

Lossless engine — honesty beats rate inflation

On FLAC, WAV, AIFF, ALAC, WavPack and true hi-res, Valve King prefers an integer pure path: decode close to the file’s native PCM, keep processing off unless you ask for colour, and open the converter at the exact sample rate of the file on ALSA Direct (hw:, exact negotiation). If the device cannot do that rate, Direct fails honestly instead of silently resampling — the opposite of a “stretch everything to 96 kHz” soft mixer.

At unity volume with valves, EQ, and SRC off, that path is designed for bit-perfect delivery of the master as stored. Your DAC then runs its reconstruction filter on the rate the music was actually authored at — 44.1, 48, 96, 192 kHz as the file says — not on a player-invented clock. Optional valve packages sit on top as a physics-led choice; they do not smuggle lossy polish into a studio file, and they do not rebrand upsampling as purity.

03

Glorious Lossy — fix the damage, not the sample clock

Perceptual codecs (MP3, AAC, Opus, Vorbis) discard energy under masking thresholds, smear pre-echo around sharp attacks, collapse stereo into joint coding, and leave grainy or sealed-in tops. None of that is cured by writing more zeros between samples. Glorious Lossy runs in the float path after a true lossy decode, only when hard gates confirm a compressed source, and targets those mechanisms in the room:

  • Pre-echo & transient re-lock — restore snap on drums and picks the codec softened
  • Harmonic continuity & formant rescue — densify body and vocal identity the bit budget thinned
  • Stereo coherence & image depth — open mid-side collapse without inventing a fake “hi-res” width shelf
  • Presence, silk, adaptive de-harsh — ease hash and fatigue where the encode is hot, not a blind ultrasonic boost
  • True-peak pad & loudness lock — keep peaks civil on float-to-DAC exit without radio loudness wars

That is listening recovery on the domain where the information was lost — psychoacoustic time/frequency behaviour — not a claim that a compressed stream becomes a bit-perfect master, and not empty bandwidth sold as detail.

Two engines, one discipline

Lossless engine: protect the master — native rate, exclusive path when the kit allows, optional valves as colour, no silent SRC, no “sauce” on studio files. Glorious Lossy: help compressed libraries and radio breathe by addressing codec artefacts in real time, hard-quarantined so FLAC and friends never enter that path. Upsampling remains available as a technical necessity when hardware demands a fixed rate; it is not marketed here as the primary way to make music sound more alive.

Compressed music that finally breathes

MP3, AAC, Opus, and other compressed sources throw away information to save space. Glorious Lossy is a listening recovery path — not a claim to recreate the studio master. It works in real time on playback, only on true lossy sources, and never rewrites files on disk. What follows is how the stages feel in the room, not a lab paper.

What it is — and what it is not

Compression often leaves music sounding boxed-in: brittle tops, thin mids, a centre image that swims, and a stereo field that feels crushed. Glorious Lossy is a stack of purpose-built stages that ease those symptoms so compressed tracks feel more whole and listenable for hours — without pretending a 320 kbps stream is bit-perfect tape.

  • Not exact science marketing — results depend on the source, your DAC, and your room
  • Not a “make everything hi-res” button — it assists compressed material; it does not invent a new master
  • Hard quarantine — FLAC, WAV, AIFF, ALAC, DSD, and true hi-res never enter this path
  • Real-time only — nothing is written back to your library

Air & top-end ease

Lossy codecs often shut the top end down or leave a harsh grain. This stage restores a sense of air and extension so cymbals and room tone feel less sealed-in, while softening the brittle digital edge that makes long sessions tiring.

Body & midrange weight

Bit-starved files go thin in the lower midrange — vocals and guitars lose chest. Body recovery brings back weight and density so rock ’n’ roll has punch again, without a muddy bass shelf that masks the mix.

Centre image & holography

On weak encodes, the centre drifts and the stage collapses. Stereo / mid-side style restore firms the vocal centre and opens width and depth cues so the image feels more holographic — instruments have a place, not a flat wall of sound.

Presence & vocal focus

Presence work keeps lead vocals and lead instruments from disappearing into the hash. You hear diction and attack more clearly, without the shouty “radio loudness” boost that fatiguing enhance buttons often add.

Transient & clarity assist

Compression smears drum hits and pick attacks (pre-echo and soft transients). Clarity / transient stages help snaps and plucks speak again so rhythm sections stay lively, without turning every track into a clicky demo.

De-harsh (when the top is hot)

Modern masters and lossy streams can spit harsh energy up high. De-harsh eases that grain and sizzle when it is present — adaptive, not a permanent dulling filter — so loud choruses stay listenable without killing air entirely.

Tight bass, not boom

Recovery aims for controlled low end: firmer kick and bass lines that start and stop, rather than a one-note boom. Paired with body in the mid-bass, rock mixes keep drive without mud.

Stability & long-session comfort

Soft limiting / ceiling behaviour on float paths keeps peaks from spitting, so compressed playlists and radio feel calmer under load. The goal is music you can live with for an evening — not a short demo blast.

How it fits the rest of Valve King

Glorious Lossy arms only when the decoder labels the source as compressed (MP3, AAC/M4A, Opus, Vorbis, lossy radio). Lossless and hi-res stay on the clean codec path — optional valves and EQ are separate choices. After the 14-day trial ends, lossy formats continue to play; a full license unlocks the complete engine set.

  • Lossy profile — full recovery stack for everyday compressed libraries and streams
  • Lean profile — lighter assist for background play
  • Pure / Valve — integrity or physics colour; lossy recovery stays out of true lossless

What you can play

Lossless & studio

FLACWAV / WAVERF64AIFFWavPackALAC

Lossy & everyday

MP3AAC / M4AOpusOgg Vorbis

DSD

DSFDFFDSD

Native / DoP where the device allows; clean PCM when that is right for your converter.

01

Pure

Critical listening. Integrity first.

02

Valve

Physics engine colour on exclusive path.

03

Lossy

Full recovery for compressed libraries.

04

Lean

Background play, lighter load.

What you need

Operating system

  • Linux x64 — current ship target
  • Ubuntu 22.04 / 24.04, Debian 12+, Fedora, Mint, Pop!_OS, and similar
  • ALSA required; PipeWire / Pulse fine for Compat mode

Hardware

  • RAM: 8 GB min · 16 GB comfortable
  • Display: Full HD 1920×1080 recommended (720p not enough for multi-panel)
  • Sound: USB DAC, interface, headphone amp, HDMI, or built-in

License — 1 PC only

  • One computer per license
  • Locks to that machine after Activate
  • Not transferable to another PC

Not required

  • No subscription to press play
  • No separate FFmpeg or .NET runtime for end users
  • No mandatory cloud account

One price. One PC. Lifetime.

£79.99 one-time — lifetime license for one PC only. Try free for 14 days; lossy formats continue after trial.

14-day Trial

Full evaluation · Linux x64 installer
Free for 14 days

Hear Pure, Valve, and Glorious Lossy on your own DAC. After day 14, lossy formats continue to play.

  • Self-extracting Linux x64 installer
  • Test exclusive direct on your converter
  • Compare valve packages
  • Lossy keeps playing after trial ends
Download free trial (Linux x64 zip)

After download: unzip → chmod +x RenniLink-Valve-King-Trial-linux-x64.run./RenniLink-Valve-King-Trial-linux-x64.run

File URL: https://download.rennilink.com/RenniLink-Valve-King-Trial-linux-x64.zip

If the button fails: the zip is not on Cloudflare R2 yet, or download.rennilink.com is not connected to the bucket. Upload object RenniLink-Valve-King-Trial-linux-x64.zip to R2 and attach that custom domain (see CLOUDFLARE-DEPLOY.md). Or email sales@rennilink.com.

Straight answers

What happens when the 14-day trial expires?

Lossy formats continue to play. The lifetime license unlocks the full product (complete Pure / valve / engine set).

Is the license for one PC only?

Yes. Locks to that machine after Activate. Not transferable. A new PC needs its own license.

Does the valve engine rewrite my files?

No. Real-time on playback only. Turn valves off for the clean path.

Is upsampling the way Valve King improves sound?

No. Inflating sample rate only interpolates; it does not restore bits a codec discarded or make a master “more hi-res.” The lossless engine keeps native rates and an exclusive Direct path for honesty; Glorious Lossy repairs compression artefacts on true lossy sources only. See Beyond upsampling.

Subscription?

No. £79.99 one-time. Offline listening is first-class.

Valve King

Putting the soul back into rock 'n' roll.

Warmth. Harmonics. The feel of the analogue era — with modern exclusive playback, honest paths, and engines that respect your masters. Put your converter in charge. Keep purity when you need it. Let the valves bloom when you don’t.

Download trial