darTZeel NHB-18NS preamplifier
The boutique company's second offering, the battery-powered NHB-18NS preamplifier, exudes darTZeelness, including a price of $23,250. Like the power amp's, the preamp's front and rear panels are finished in a dark gold that was a taste no visitor to my listening room managed to acquire. Not helping the Gold Acceptance Factor was the unusual retro-industrial red of the chassis, which was reminiscent of (take your pick): Radio City Music Hall before it was renovated, an 8mm projector from the 1940s, or an Erector set. Contrast the red and gold, add the two knobs' red LED backlighting and the three butterscotch indicator lights, and if it weren't a piece of electronics and didn't weigh 50 pounds, I could imagine finding one of these in Lauren Bacall's purse. But I ended up liking and understanding the NHB-18NS's warm, vivid color combination: The preamp looks like it sounds.
An interesting choice of features
While the NHB-18NS lacks some of the features found on microchip-driven preamps festooned with fluorescent screens, its functionality could hardly be called minimalist. That's good—a $23,250 preamplifier should pretty much be able to do everything but put the record on your turntable and lower the stylus into the groove. (By the way, NHB stands for "not heard before," NS for "no switches.")
The NHB-18NS features six inputs: five unbalanced RCA (one is for the built-in phono preamp) and one XLR. Four of the inputs also have selectable 50 ohm BNC Zeel jacks.1 There are six outputs: one unbalanced, one XLR, one unbalanced, a buffered tape Out, plus three 50 ohm BNC darT connectors for use with the NHB-108's 50 ohm BNC Zeel input.
According to the NHB-18NS's preliminary manual, the multiple BNC outputs are for biamping and triamping, using filters built into the preamp. All will eventually be described in detail in the manual's final edition, but basically, these are "rough" first-order filters designed to reduce IM distortion by separating and limiting the frequency ranges reaching the speaker drivers. They are not meant to replace speaker crossover networks.
A three-position toggle switch just below each unbalanced line-level input RCA jack provides 6dB of attenuation for high-output sources, or 50 ohms input impedance for future darTZeel source products. The XLR input has two toggle switches: the upper one lets you select an input impedance of 600 ohms for professional audio gear or 6dB of attenuation, and the lower offers three grounding possibilities for the XLR chassis jack: Floating, Chassis (100-ohm resistor to chassis), and the default position, Ground.
The front panel has an input-selector knob that darTZeel fancifully calls the Enjoyment Source, and a volume knob salaciously labeled Pleasure Control. Between the two knobs is not a button labeled Push-Up Bra, but the equally unlikely Power Nose. Surprisingly, the balance knob is labeled Balance. Not surprisingly, it's not your standard balance control: There's no change in balance until you've rotated the control ±5°. At full right, the right-channel level increases by 3.5dB, while the left decreases by 3.5dB, and vice versa at full left. This provides precise level adjustment while maintaining the overall volume level.
Two toggle switches mounted directly under the Power Nose offer controls for Mute/Home Theater Bypass and Mono-Stereo/Dimmer. A quick flick of the former mutes the system. Hold it down for about seven seconds and the Mute LED turns green, indicating that the selected input has bypassed the Pleasure Control and is set to 0dB gain, where it will remain until the next seven-second press. The other switch toggles between Stereo and Mono output; holding it down for more than five seconds switches off all lights and LEDs. You can also extinguish the illumination via the minimalist remote control (which is nicely milled of aluminum) by simultaneously pressing the volume Up and Down buttons. Other than volume, the remote offers a Mute button.
A small, unobtrusive-looking stainless-steel box containing the power supply/battery charger connects to the preamp's rear panel via an umbilical, and to your electric service. There are no AC transformers in the main chassis.
I'll spare you the various LED status indicators, except to say that they're logical and informative: Should the four batteries run down, the center LED glows red to tell you that the NHB-18NS has switched itself to AC mode. However, that's not likely to happen as long as you remember to turn the unit off after listening; a single charge is said to be good for well over 10 hours. I never did see that LED turn red, meaning that my review sample was never AC-powered during Enjoyment, and the batteries were charged when the NHB-18NS was turned off. (I usually need charging after Enjoyment.)
Unless its batteries are completely drained, the NHB-18NS automatically powers on in battery mode. Even if partially discharged, the unit will run on battery power; relays disconnect the AC input from the power supply when the NHB-18NS is powered on.
Using the Nose to achieve Pleasure and Enjoyment
The NHB-18NS preamp was ready to go about 10 seconds after I pressed Power Nose. Perhaps because it's battery-powered, the NHB-18NS seemed to require no warmup to achieve ultimate sound quality. However it sounded after three hours of listening was how it sounded as soon as it was powered up, or extremely close thereto.