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Mini Review: Luminous Audio Axiom II “Walker Mod”

Sometimes, I think I'm losing my mind. Other times, I know it's gone and I just sit around fondly recalling all the good times we had together. Case in point -- I could have sworn I posted this two or three months ago. What have I lost (along with my mind and memory), you ask? Why, a lovely little side trip down passive-attenuator lane.

A couple of months back, I got a really sweet little passive from Tim Stinson over at Luminous Audio. Luminous makes a variety of interesting audiophile bits, including some cables, but look ’em up on The Google and you’ll find reference to their extremely budget-friendly Axiom preamplifier. Starting at $195, the Axiom is simplicity itself. You wire in an input, wire in to an output, and you’re done. No power. No fuss. No muss. No greasy aftertaste. In fact, let me underscore that last bit — assuming you have a low-Z output source and a high-Z amp, you’ll hear nothing from the Axiom. It’s not there. “Open window”? Umm. No. What window? There’s nothing to get in the way of the music. And this is exactly what a great passive preamp does — nothing at all.

I say this like you’ll “get it”. In case you didn’t, here’s the truth — most preamps suck. And I mean that literally — they suck the life out of your system. A cheap volume pot, an average-to-middling design, and all you get is a link in your audio chain that can and will introduce noise, destroy resolution, and most probably just fuck everything up. I mean, not to put too fine a point on it or anything. Ahem.

But it’s true! A good preamp is a rarity. One that doesn’t color the sound, or alter the response, or steal detail or rob the life of your signal — at least to some extent — is something of a marvel. Which is weird, if you think about it. A preamp has two jobs — attenuate the volume from “unity” (all the way up) and switch between sources. Ideally, a good preamp will do the former in a sonically transparent way. If you’re lucky, it’ll also let you do both volume and source-switching from the comfort of your overstuffed chair. But every circuit, cap, transformer, resistor or switch in that signal path is, potentially, a sniper on the road to sonic nirvana. And improper, cheap, or simply bad grounding on a preamp can kill everything in the chain.

Which is why a lot of folks are going “DAC direct”.

With no preamp in the chain, there’s fewer components to fuck with the sound quality of your system. Good thing, right? Well, sometimes. Most DACs are lousy preamps, despite their “superior” digital volume controls. The analog section on a preamp — a good one — really needs to be robust, and that’s something a cheap DAC doesn’t usually sport. And lets leave aside the question of value in doing attenuation in the digital domain.

Anyway, for folks with a significant investment in an analog rig, DAC-direct isn’t really a viable option. Sure, there are DACs that do encoding on the fly, but if you’re an analog guy, the very notion will probably make your skin crawl. So, no. Something else must be deployed. Release the flying monkeys!

Failing that, I’d like to suggest you try out a passive.

Not every passive is the same. In fact, Luminous Audio has four.

  • Axiom II RCA version ($195)
  • Axiom II XLR version ($299)
  • Axiom II Multi input ($349)
  • Axiom II “Walker Mod” ($399 RCA/$499 XLR)

The first three are pretty much of a piece — one input, one output, with an Alps Blue volume pot in the middle. Additional inputs and outputs can be added on, along with upgrading the Holco resistors to Caddocks. Things get a bit more interesting when you move to the Walker. The resistors are all Caddock by default and the Alps pot has been traded in on a “custom-made, silver-plated stepped switch based on 1% metal film resistors”. New footers, upgraded wiring and some top-notch RCA connectors from Vampire round out the offering.

This is, in essence, a volume control in a box.

I had a chance to use the Axiom II Walker with a couple of different amps, including a 1-point-something watt per channel Yamamoto A-08S stereo amp and a BorderPatrol SE300b tube amp, one of my favorite SETs on the market today. WyWires makes perfect cables (extremely low capacitance) for a passive-to-amp connection, so naturally I grabbed a fistful out of another rig and dragged them into active duty here.

What I heard? I heard $400 kick the living shit out of some very expensive gear.

Look, a passive isn’t for everybody. The complete lack of a remote control is annoying. Of course, I’m a lazy bastard, so take that for what it’s worth. Hmpf. Anyway, you know what else is annoying? Grain. Good thing that’s totally lacking with the Axiom II Walker. Bass response, typically the problem with a passive preamp, was strong. Like, Darth Vader voice over “the Force is strong with this one” kind of strong. No issues there. The stepped attenuator was invisible and as far as I could tell, and with my super-low source impedance (the Accuphase has a 50-ohms output) and my ultra-low capacitance interconnects, the system’s sound quality suffered not a jot. Clean, clear, extended — and all with no power cord. As my daughter likes to say, “that’s so weird”.

Compared to my current reference preamplifier, a $1,995 Wyred4Sound STP-SE preamp (also a passive, but with a remote control), the sound playback was virtually indistinguishable. The main issue I had was ensuring proper gain — given that a passive has none, it’s all up to your amp/speaker pairing. If you’re amp’s gain is low (like the Yammy or the BP amps), then it’s up to your speaker. With the Volti Vittoras, and their 104dB sensitivity, this was a non-issue, but with my middling-sensitivity speakers, it became an issue fast. Pairing the Axiom with the First Watt J2 and lighting up a pair of Joseph Audio Pulsars, I had to crank the volume all the way over and then some. Not an issue in most “real world scenarios”, but just wanted to throw that out there — this passive, like every passive, isn’t a jack-of-all-trades. It has limitations, but working within them, you’re gonna be surprised how far $399 takes you. I was.

In fact, it was this sort of experience that led me to start exploring the whole passive thing. There are lots and lots of offerings out there, but for my money and based on what I’ve heard, the Luminous Audio Axiom II is an outstanding entry on the preamp field. They’re local, too — just down Virginia way. Local is good!

Anyway, I still can’t get over how much you get for how little you pay. This is the very definition of value according to the Julia Rule. Most Wanted material, all the way. Nice work.

Get your Occasional now

1 Comment on Mini Review: Luminous Audio Axiom II “Walker Mod”

  1. It’s refreshing to read a review that is honest and includes 4 letter words. Bravo. If they don’t like it, fuck em

4 Trackbacks / Pingbacks

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  4. Looking for recommendations - Passive and/or low gain preamps ...

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