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Because of the considerable rear pressures released by the twin woofers, Zu has reinforced the Hypex amp's mounting plate with their own gasket-sealed aluminum plate which is bolted with ten screws to the SuperPly hull. Removal of this assembly involves strategic heating to loosen the seal and thus isn't recommended for the simply curious.
Exclusively for non-bridged main amps (!), Zu supplies a jumper cable to the plate amp's high-level input. Your single speaker cable connects to the main input above and that's that. For bridged main amps, use the low-level Hypex input instead. If you wish to bypass the plate amp altogether, remove the bass-amp-out/woofer-in jumpers from the twin terminals and connect your external bass amp/s to the lower terminals.


For default settings with the high-level connection and to get started, Zu recommends the sub level control at 10:00 o'clock, the sub frequency control at 9:00, the low bass EQ at +6dB and the Bass EQ frequency at 20Hz, with sub phase at 0. Bruno Putzeys' UcD module is very voltage tolerant and as promised, his inbuilt amps are dead quiet on my utility power that I've measured as high as 258V (240V nominal).


Removing the plinth for a look-see reveals the crammed space and considerable design skill involved to hide the woofer mounting bolt heads from the front baffle. These 10" woofers are identical to what's in the Definition 2 by the way, run in parallel to present a slightly higher than 4-ohm load with a combined 94dB sensitivity.


The widebanders are pair-matched electrically (for impedance, amplitude and sensitivity) and on tone. The latter has Sean involved in free-air tests facing a fixed rig, listening to click tone and sawtooth signals. After rebuilding the tweeters for voice coil alignment and neoprene glue fitting of certain critical parts, they're pair-matched by ear as well. The Mundorf silver/oil cap and paralleled Kimber cap on the tweeter high-pass are then matched to better than 0.1% tolerance (and that's no typo).

With the revised widebander, the impedance seen by the main amp now sits above 16 ohms to make low-power tube amps very happy indeed. After the 7-day non-stop break-in at the factory (1 watt power input during the day, 50 watts during the night), Sean recommends three days of playing in the home to enter the performance sweet zone and hear music. 30 days later, you've arrived fully.
Sidebar 1: "Once Adam and I had finished up all the whatabouts, engineering, subassembly run-ins and testing on the Presence, we decided to invite local Ogden hard core troubadour Dan Weldon to lend his skills and ears for voicing and system tweaking. He grabbed a car load of guitars along with his Porch Board and a few of his favorite mics and drove on over. We spent a few hours each day for the next few weeks having Dan plugged directly into various iterations of the Presence..." continue

For those not keen on mirror gloss finishes, Zu has introduced their new Smooth Matte*, a German product soft to the touch, completely non-reflective and apparently tough as nails on chemicals, water and other cleaning agents while pulling no hairs or dust from cleaning rags. About 12 colors will be standard but Adam thinks there'll be easily 30 tones prior to any custom mixing so once again, the interior designer should have free reign.
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* "Zu Smooth Matte is unbelievably durable. Gloss, in contrast -- even the best automotive clear coat finishes -- lacks resistance to scuffs and swirl marks. Gloss looks good when new but after it has been dusted a few times, you end up with 'swirl-gloss'. With Zu Smooth Matte you get total immunity from swirl; and you no longer need to fear the accident rub with a zipper, buckle, snap or button. It may well be the toughest matte finish ever. Zu Smooth Matte process also improves the cabinet performance as well as the playback rooms acoustics. Compared with gloss finishes, Zu Smooth Matte improves the cabinet in several ways. First, a much thicker composite substrate can be realized which aids in the acceleration, distribution and damping of acoustic energy of the cabinet. Second, the final coating damps vibrational energy of the composite substrate and reduces the transmission of vibrational energy on the cabinet to the air. The final coating also defuses and absorbs sound within the listening space, like well-placed invisible room treatment panels.
"Unlike many other matte coatings and processes, Zu Smooth Matte does not react to hand oils, halides and dirt. In fact, once cured it's pretty much impervious to wear and tear as well as chemicals. Many other matte finishes will 'shine' from simple handling. Zu Smooth Matte will not show fingerprints or react with anything that might be on them. Zu Smooth Matte is impervious to
Sidebar 2: A few more pictures of Zu Audio speaker production and after-work activities... continue
to water, oils, acids and anything else you might have in your home or garage. Zu Smooth Matte is a catalyzed, very high solids product, which is a lot better for the environment and people compared to lacquers and traditional finishes. And being a high solids catalyzed product, Zu Smooth Matte will not fill your home with harmful fumes - full outgassing on automotive clear coat is a minimum of three months. The durability and wear resistance is so high on Zu Smooth Matte that you don't have to worry when handling, packaging or shipping your speakers. Not a chance in hell you can say that about any of the current gloss finishes. For cleaning, we recommend a damp microfiber cloth."