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Reviewer: Srajan Ebaen
Sources: Zanden Audio Model 2000P/5000Signature
Preamplifier: ModWright SWL 9.0 SE; Music First Audio Passive Magnetic

Amplifier: Terry Aben DIY Aleph H, FirstWatt F1 [on loan], First Watt F3 [on review]
Ear speakers: AKG K-1000
Interconnects: Zu Cable Varial
Power cords: Crystal Cable Reference
Power conditioner: 2 x Walker Audio Velocitor S
Retail of review product: $399+

AKG's earspeakers called the K-1000s have the potential to be one of the world's very best dynamic headphones. I say potential because, in stock form, they're compromised and flawed. To unleash their full potential, ex Sennheiser engineer James Serdechny of Stefan AudioArt has now authored the 20-ft hard-wired replacement cable. The stock 'phones use a Y'd pig-tail into a 4-pin XLR. See above right [pin 1 left positive, pin 2 left negative, pin 3 right positive, pin 4 right negative]. Then the opposite XLR segues into a cable length terminated at speaker-level in pins or spades. The obvious address for improvement is to replace the Neutrik/spade portion. Plug'n'play. That's how I've listened to my Ks for more than a year. Stefan AudioArt's partial harness [left cable coil above] replaced the stock tail. Alas, Serdechny promises a lot more performance is possible. Toss the remaining hardwired stock harness upwards of the XLR. Replace it with something far more choice and appropriate for the job. Since this would require unsoldering and resoldering, I should chuck the ringy metal grilles I'd have to dismount to get at the innards and henceforth go nude. That didn't scare me. Not for nothing are we called the moon men. I did say serious.

Depending on whether you'll drive your Ks from an amplifier's speaker binding posts or from a headphone amp outfitted with the requisite 4-pin XLR (and enough power behind it to properly drive these notoriously inefficient cans), Serdechny's cable can be terminated XLR, small spades, big spades, bananas or pins. Pricing ranges from $399 for silver-solvered ends to $449 for premium bananas, with all other options bracketed in-between. Lengths beyond 20' are available. E-mail the maker for a quote.

Since I have commissioned Terry Aben in Canada to build me one of his Nelson Pass derivative Aleph H headphone amps with a 4-pin XLR in parallel to the obligatory 1/4" jack, I'd asked James to dispatch the review loaner with said Neutrik. "And include an invoice, James". My experience with his cables in the past had me supremely comfortable. I'd want to keep this one. Plus, it'd be hard-wired to my personal 'phones already. Was I gonna reverse the operation even if the results were only as good as before? Not likely. Very unlikely too that I shouldn't hear improvements. So the deal was struck, the cable sent, the invoice included, with sonic observations forthcoming from a -- hopefully proud -- owner.

Technically speaking, what's the diff between the hardwired (full-on) and tail-end (partial) replacement cable by StefanAudio Art? "We get this question often. The hardwired K-1000 does not have the stock cable portion to compensate for so the gauge is higher with a very different strand configuration. The hardwired K-1000 incorporates our more extensive and expensive proprietary wire treatment process with a multi-strand configuration developed to bring the AKG K-1000 headphone to their full sonic potential." Adds the website: "Significant increase in soundstage. Added richness and extended lower frequencies. Dramatically warmer midrange. Naturally balanced high frequencies. Construction: 4-conductor quad-braid field geometry consisting of medium gauge ultra high purity copper with individual strain isolation enclosed with a Teflon Oxygen dielectric finished in black Techflex with color matched professional 4-pin XLR connector and a choice of high quality connections to the amplifier. All connections are applied to the cable with Stefan AudioArt's exclusive Ultra-Solder Process (patent rights issued and/or pending)."

From the improvement list promised by the propaganda, soundstaging would rank low on my list. The AKGs as is already run circles around pretty much anything else in headphone land. Competitors try to sneak closer with electronically actuated cross-feed circuits. Not the same, sorry. "Added richness and dramatically warmer midrange", however, would be very welcome indeed since that's a genetic weakness of the Ks. It has led many an owner to experiment with tube amps. "Naturally balanced high frequencies" is a definitive liability of the stock cans and ably addressed already by Serdechny's partial replacement cable, albeit not completely. In short, three out
of four improvement categories claimed for the modification were not only high on my list but their very articulation suggested a keen understanding about what the AKGs still left on the table. Promising promises indeed. Getting at the goodies -- or baddies as it were -- requires a sharp fine-tipped Phillips screwdriver to loosen two bolts per ear piece in the frame. One is openly visible [above], the other is hidden a few inches over underneath the exit flap of the cable. Needless to say, you'll also need a soldering iron, a solder snuffer and a steady hand. Remember, electronics don't like unduly long exposure to extreme heat. It rapidly travels down from the immediate area of attack to melt downstream insulation and cause other possible damage like unseating joints. Have your iron hot, your tip clean and act like an insurgency team - fast, precise and effective.

El nudo. Above is what you'll end up with if you chose not to replace the grilles. Here's how you get there. Undo the two small screws at the bottom of the frame. The grooved frame sits in two retaining pins at the bottom of the ear pad. By gently lifting up each lower L end, the frame snaps off easily. The black plastic pads with the drivers mounted to them attach to the hinge via two larger retaining pins (their negatives are visible in the right 'phones above the drivers). Some soft glue attaches the mesh grilles. Remove them. If the earpiece itself comes off the hinge in the process, don't worry - it'll get fixed later when you reattach the frame.
Now undo the two Phillips screws that mount the circuit board to the frame. Before you can remove the circuit board to get underneath the coil and unsolder the stock cable leads, you also need to unsolder two pins. In the above photo, those are hidden inside the two solder patches directly left of both screws. To the left, you see those same two pins hard-mounted to the plastic substrate. Make sure those pin connections are desoldered first or you'll break the board. Vital: Make sure to not tear off the voice coil leads to the diaphragm [closeup below].
What the closeup should bring home once you consider how much it is magnified? These wires are so thin, they're barely visible to the naked eye. I shore off one set in one earpiece. Hurray for the wisdom of hindsight! With the circuit board safely loosened, unseat the stock wires [right]. Resolder the replacement cables in accordance with the enclosed color coding directions for each channel. Important: Fish the wire first through the rubber strain relief, then the frame cap (the end with the two screws you removed in step 1) before you solder the new wire in place. Forget that and you'll set yourself up for curses later on.
To left, the ear piece with the circuit board removed and the voice coil wires unharmed. Note the cable channel to the right of the central exit at the lower lip. The new cables underneath the circuit board have to be routed such that they fit inside that channel without blocking the right screw hole.

The AKGs clearly weren't designed to be friendly to amateur modifiers. There's very little room to maneuver. Take your time. A steady hand is paramount. Proper tools like needle noise pliers, a small-tipped screw driver and a thin blade are helpful to assist in removing and reinserting the circuit board, carefully routing the wires and redoing first the screws, then the two pin solder connections.

Post surgery and if the grills are not refitted as is recommended (they do resonate while also providing physical protection), the denuded K-1000s appear exactly as depicted already above.

Having botched up one earpiece and feeling reasonably certain that resoldering those gossamer VC leads hadn't come off properly, I expected sound out of only one channel. Disappointingly, I got no sound.
Time to pull out the continuity checker and retrace my steps. I'll also have to borrow Ivette's magnifier lamp or stand no chance in hell to ever properly resolder those voice coil leads.

Once I figure out where I fouled up, I'll document the error if it's likely that you might make it as well. Wish me luck. I'd hate to think I butchered my beautiful 'phones in a fit of upgraditis...