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Reviewer: Srajan Ebaen
Source: Zanden Audio Model 2000P/5000S
Preamp/Integrated: ModWright SWL 9.0SE; Music First Audio; Hyperion Sound BEC-P25T
Amp: 2 x Audiosector Patek SE; Yamamoto A-08S; Canary Audio CA-308s; FirstWatt F3
Speakers: Zu Cable Definition Mk 1.5 Pro version with Rane PEQ-55; Gallo Reference 3
Cables: Zanden Audio proprietary I²S cable, Zu Cable Varial and Ibis, Zu Cable Birth on Definitions; Stealth Audio Cable Indra, MetaCarbon & NanoFiber [on loan]; SilverFi interconnects; Crystal Cable Reference power cords; ZCable Hurricane power cords on both conditioners
Stands: 1 x Grand Prix Audio Monaco four-tier
Powerline conditioning: 2 x Walker Audio Velocitor S
Sundry accessories: GPA Formula Carbon/Kevlar shelf for transport; GPA Apex footers underneath stand, DAC and amp; Walker Audio SST on all connections; Walker Audio Vivid CD cleaner; Furutech RD-2 CD demagnetizer; WorldPower cryo'd Hubbell wall sockets
Room size: 30' w x 18' d x 10' h [sloping ceiling] in long-wall setup in one half, with open adjoining living room for a total of ca.1000 squ.ft floor plan
Review Component Retail: $650/pr
Lloyd Walker is certifiably insane. "If it ain't broke, don't fix it." He's so nuts, he doesn't know anything about that time-honored code. He's a very simple fella. He only knows one thing. The best he can do today won't necessarily be the best a year from now. Experience and improved parts might tease him to revisit a design. It's this fiery brand of Lloyd lunacy or Walker whack that has endeared the man to many 'philes. Not only has this acclaim garnered his products many awards and enthusiastic followers, he's even gotten personal awards - as an audio luminary and tweak maestro par excellence. Simply put, Walker's a never-ending trip. He'll only be stopped when his clock expires.

Very few know that he's built OTL amplifiers. Or that he's been listening to a line stage that's still not available to the greater public or announced on his website. Walker's incessantly tweaking until he's confident that for now, nothing's left to improve. As he tells it, he wasn't really looking to revisit his Ultra Definition Links. Those are external Zobel filters. They strap across your speaker binding
posts like the Foundation Research NL1 Noise Loads sold by Music First Distribution which reader Larry Phillips brought to my attention. These devices filter out ultrasonic noise that's riding on your cables-as-antennae due to increased radiation pollution from cellphones, satellite transmissions and other wireless data transmission protocols. And while ultrasonics are inaudible -- that's why they're called ultra -- their intermodulations with the music data leak into the audible band. So the HDLs are filters. They kick in deep inside the MHz band and operate well into the GHz range. Just how effective their action is should depend a great deal, one imagines, on the actual amount of high-frequency garbage in your neck of the woods. Neck of the woods? How about the far more likely scenario of metropolitan high-rise apartment surrounded by megawatt radio broadcast towers and high-speed wireless repeater stations? Never mind those ordinary wireless 2.4GHz 'phones.

Walker blames the launch of the Reference HDLs on design work he's recently finalized for his phono stage, particularly the availability of new custom capacitors and resistors made for it to his specifications. You see, something had kept nagging inside Walker's balding noggin. As many HDLs as he'd already sold in their various incarnations, the bloody things weren't working on his own reference speakers, Kharma Ceramique two-way floorstanders. Either the speakers were too good to not require them or the HDLs weren't good enough to improve upon them. Whatever. It pissed him off as a battle that still needed to be won. You simply don't present Walker's ongoing tinker Jones with a brick wall. He's not the kind of psychic who acknowledges that he can't read his own future.

A number of key clients become Walker's first test bed for new discoveries. His Proscenium Gold Signature turntable is a financially very rarefied beast indeed, hence Lloyd's tables tend to find themselves in systems of equally rarefied stature. Just the ultra-resolution context he thrives on working in. By the time I learned about the Reference HDLs, they'd already made the rounds. More importantly, they'd finally brought his Kharmas to their knees. Taking them out was no longer an option.

For Walker's many-tentacled product mix, design work is an endlessly cross-referencing inter-disciplinary process. He hears about a new part, he tries it. If it works as advertised, chances are he finds a way to improve upon it for his application. Whatever he discovers during that process gets applied elsewhere too. In this fashion, a tonearm discovery might morph into a new hookup wire for a particular juncture inside his linestage. A new chemical he reads about could find itself mixed into his Ultra Vivid optical enhancer for CDs and DVDs. His Super SST contact enhancer gets applied to the spark plugs of his motorcycle and Walker dutifully logs improved fuel consumption and delayed clutch shift requirements. A modification he does on his personal DVD player
morphs into an idea that, for now, gets filed away in his bio computer called a mutant brain. And there's no telling by what strange process of synaptic short circuiting and wire crossing that computer one bright morning will whisper into Walker's ear with a tantalizing effrontery. What if?
The Reference HDLs, like their predecessors, must be installed in correct marked polarity and atop the speaker cable spades, not between them and the terminals. With Walker tweaks, it's best to follow instructions to the letter. The man sweats the details and so should you. Needless to say, make sure your installation doesn't shorten out your main connection. Being ultra-pure silver, the HDL leads bend easily so position them out of contact with anything except for the actual spades but also bend them as far as possible away from the terminals to avoid the fields generated there.

The copper-foil shielded wood body contains one denuded resistor and one naked cap. The leads and spades are hyper-pure silver. Everything is deep immersion cryo'd, first as individual parts, then again as the full final assembly. Asked whether he could divulge anything further, Walker declined. "Anything I make always gets copied. I'm sick and tired of it. Let others figure this shit out for themselves. I ain't giving secrets away no more." Take that, rip-off artists! Everyone else, give the Reference HDLs two to three days after installation before proclaiming final judgment. If you're not convinced of their efficaciousness and sonic benefits, return them within 30 days in original condition to get your money back.

Should you spend $650 on two tiny minimalist gizmozoids if your speakers are worth $1,500? Should you go HDL if your electronics are still parked on a ringy metal contraption with glass shelves? If you haven't yet addressed an 8dB room-induced peak at 70Hz? The list of things you should probably do before considering HDLs is formidable. It's all about priorities. First get the biggest obstacles -- source resolution; speaker/seat alignment with regards to matched path lengths and room modes; amplifier/speaker matching; room acoustics; resonance control; power distribution; cable voicing -- handled so that the resolving power of your system is sufficiently keen to make more advanced tweaks obvious and worthwhile. Sufficiently dialed rigs become transparent to little changes.

This includes the occasionally profound effects which such apparently tiny changes may cause in excess of ambitious expectations. Reviewer raves over tweaks must always be tempered by context. Don't believe that such devices could substitute for fundamental steps that haven't been attended yet. First things first. Those are the basics. As such, the Reference HDLs certainly aren't basic. They are advanced après tweaks for after when everything else is in place. End of small print. Let's get on with these copper-wrapped minis. I installed 'em across the terminals of the Zu Definition Pros to ultrasonically filter the frontal 35Hz-and-up arrays of the two wide-band drivers flanking the phenolic horn-loaded tweeter. The quartet of rear-firing woofers per speaker were left au nature.

And? Morpheus to Neo: Open your mind. This is one of those tweaks that threatens the credibility of anyone stating honestly what he or she hears. As such, it's convenient to underwrite or return the product with a little note. "Loved it but I'm not gonna write it up. I can't afford the ridicule. Sorry. I'm sure you understand." Signed, "Chicken". That's because the improvements are unexpected, at least to anyone without the engineering credentials required to understand how and why such extreme ultrasonic filtering should exhibit these effects (at least as implemented here). There are parallels to superior subwoofers and ultra-tweeters in how those impact the opposite end of the sonic spectrum that's apparently addressed. Ultra tweeters improve midrange and bass, subwoofers -- among other more expected things -- treble sweetness and upper midrange body.

Accounts to confirm this are legion. Solid explanations for how that works? Still elusive. That's presumably because it requires a more scientific understanding of psychoacoustics than we currently possess. The Reference HDLs are broad-band devices in their subjective effects while their actual activity is restricted to completely inaudible bands. The closest parallel in my experience is going from the Zanden transport's standard digital output (S/PDIF) to the I²S option with its additional reclocking feature. There's more resolution, clarity, suchness, definition and focus as though some subliminal shake or indecision had been stabilized. Think antique copper coin that's been submerged in the ocean for centuries. The salt corrodes what to its contemporaries must have been a finely minted lost-wax surface. Depending on age, the sharp relief has gotten softened, its finest features blurred or erased.

Comparing the music pre and post insertion of HDLs, the music without them sounded like older coins. With the HDLs installed, I upgraded to special edition releases fresh off the Franklin Mint. Okay, reviewers are often accused of flowery language. True enough. Still, some of us actually struggle mighty hard and with considerable deliberation to come up with concrete examples that describe, as precisely as our command of the language affords us, things that are very hard to describe. Talking about partially corroded versus fresh coins in this instance is a fitting visual. Whatever the currency face depicts is clearer and more intelligible on the non-corroded coin. You're not sweating specific details -- treble, midrange, bass in our case -- but look at the whole surface to recognize whatever ancient ruler, writing or value designation was lovingly inscribed by its creator. Just like that sharper relief makes details far easier to recognize, the improved audible sharpness or accuracy that results from the installed Reference HDLS doesn't mean edgier but the opposite. Things are clearer & crisper and sweeter & easier on the ear - simultaneously

But this is not a hit-you-over-the-head affair that kicks in like a turbocharger when you first install these things. Leave them in for a few weeks while you wonder what, if anything, they're up to. Then take them out. When things now instantly revert to what they were before, you'll know exactly what the HDLs did. Depending on the overall resolving power of your rig -- its dialedness -- you could feel condemned to having to revert back to the HDLs pronto, explanations and cost be damned. Or you might haggle over whether whatever improvements you noticed couldn't be gotten some other way.

With that, I can't help you. That's what Walker's satisfaction guarantee is for. What I can say is this: As you claw up what our own Chip Stern calls Mount Compromise, it tends to take larger and larger sums for smaller and smaller advances. It's exactly like oxygen-starved mountaineers describe it. The higher you climb, the harder you have to fight for each step. Each new meter becomes a major physical effort. In audiophile terms, that's many thousands of dollars, perhaps by way of cables, perhaps by way of a new CD player. It's admittedly frustrating to realize that even with a bleeding-edge $40,000 digital front-end like my Zanden Audio separates in the system, improvements continue to be possible. Naturally, the room is the first and last frontier. It's usually neglected or completely overlooked. That makes 'philes going off on tweaks, cables or full-blown component swaps seem unbelievably ignorant and misguided to acousticians or anyone really thinking things over.

On the hardware side of that equation, Lloyd Walker's latest tweak at $650/pr might at first look silly expensive for what it appears to be - a few minuscule parts custom-made, hand-fitted and shipped to a cryogenic plant twice during the process. Then you ask yourself. In a high-resolution context, could these particular improvements be achieved some other way? Superior mechanical resonance control in many ways is comparable to the Reference HDL effects by raising broad-band resolution and subtracting distortion. There we're talking ca. $1000 per tier for an equipment rack like my Grand Prix Audio Monaco (readily more if you opt for the best by HRS or Finite Elemente).

The thing is, I already own two Monacos. The Reference HDLs still make a very appreciable difference (btw, I don't have experience with ultra-performance universal external Zobel filters outside of the Walkers to feel comfortable making ultimate statements by way of what else might be available in the market). Rather than mechanical resonance attenuation, the HDLs address radiation pollution. It's our collective inheritance of the 21st century. And it ain't getting better but worse. Though I live way out in the country, to do what I do requires a wireless mini satellite on my roof to enjoy high-speed Internet access. Then there's my cellphone (8-9MHz) and wireless 2.4GHz handsets on the land line. There's the broadcast tower of KTAO, our local radio station. There's the 30-50MHz police communications band, traffic radar (1,300 - 1,600MHz), weather radar and government bands (up to 300GHz). There's satellite-style cellphones in the more remote canyons and mesas of Taos which otherwise would enjoy zero connection to the outside world. There's repeater antennae for the regional ether networks. There's satellite TV and radio. There's military and spacecraft communication bands.

Unlike other tweaks which insert farther upstream into the audio chain, the Reference HDLs attach as close to the chain's end as possible - the speaker binding posts. This makes sense. It avoids picking up more garbage between the filter and the final devices which translate electrical currents into physical motion - the loudspeaker transducers. The only thing more downstream still would be hard-wiring the HDLs to the input tabs of the actual drivers. That'd mean one $300 HDL per driver. I'm sure Lloyd has already thought of that for his personal installation. For those of us less stout and not living inside a copper-lined Faraday cage, there's the Reference HDLs to simply strap across the external speaker posts, easily taken out should you change transducers. Highly recommended once basics have been sorted out and satisfactorily addressed. It's like upgrading from a very good tube preamp that suddenly seems fuzzy, veiled and somewhat indistinct when compared to a superior transformer-attenuating piece like my Music First Magnetic Passive which has less noise (no noise to be precise) and plainly higher resolving power. More resolution does not equate to less musicality. If it's real resolution, it's a further reduction of distortion and simply more signal. Only fake resolution (i.e. the illusion of more detail arrived at by altering timbre or tonal balance relationships) introduces ultimately unsatisfactory side effects. Real resolution invariably sounds more real. True, if the recording has issues, that reality will be more realistically conveyed as well but certain recordings previously considered bad might surprise you and sound better now.

I do occasionally wish for a solid engineering background. Then I could better sort the fake gold from the real gold and know. Alas, I likely wouldn't be doing audio reviewing for a living then. I'd be designing stuff by the good book to still have blokes like Walker clean up after what that approach overlooks. As Bob Marley might have crooned: "No tweaks, no cry." The refrain would then have added: "No tweaks, no luv." The crying part, naturally, relates to why some of these tweaks work. Why they cost what they do. How much they piss off certain by-the-book engineers who already throw conniptions fits over cable differences. The luv is obvious too. Tweaks like the Reference HDLs work just as advertised. They clearly do something that's plainly audible. That leaves only one variable. Do you appreciate what they do for what they cost? There's one further consideration to throw into the mix. Since radiation pollution isn't imaginary but real, perhaps effective antidotes belong higher up on the totem pole of audio importance than suggested? With a 30-day return privilege for the Reference HDLs, you decide. I'm convinced they do what's claimed. They're resolution enhancers and distortion reducers that operate in an area not addressable any other way except perhaps with ERS cloth or ZSleeves (which our own John Potis couldn't do without after he reviewed 'em).

I'm only out in the cold on one count: understanding fully why eliminating bat-whisper and spy broadcast stuff on the audio lines would be so across-the-board appreciable on music. Insert big words like intermodulation effects and such. That still doesn't mean I understand it, exactly. But just because many of us don't understand doesn't mean it's weird, bullshit or pure marketing without substance. Sciene only looks like magic if you don't understand it. Neo to Morpheus: "Okay, give me the damn pill. I'm ready to take the leap now. $650 for where I'm headed seems a small price to pay."
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