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I own Bliss Hifi, a high-end audio boutique based in Minnesota. These NBS Universal II mono power amplifiers are in on consignment. They are a matched pair in the copper finish with a beautiful clearcoat over machined aluminum. The amplifiers were a reviewer demo pair that remained in the reviewer’s possession at the time of Walter Fields’ passing. They are in near museum-quality condition for their age (12 to 14 years old) and in perfect working order, lightly used as it has been in storage for the majority of the time since its release. This is an exceptionally rare opportunity. NBS amplifiers were produced in very small numbers and are virtually never available on the used market. Original retail was $18,000/pair.

Original shipping boxes are not available, but the amplifiers will be packed securely for shipping. These amplifiers were meant to be paired with NBS cables, and matching NBS Black Label Junior power cables are also available in a separate listing.

Walter Fields was an engineer who believed that power was a first-order problem. While most amplifier designers accept whatever the wall outlet delivers and focus on the audio circuit, Fields treated the power system with the same rigor as the signal path, and the Universal II reflects that philosophy in every stage of its design. The AC mains input is power factor corrected, a technique that reduces harmonic contamination of the incoming power and improves efficiency. Very few high-end amplifier manufacturers attempt this because it is genuinely difficult to implement well. The DC converters operate with zero-current transitions to prevent electromagnetic interference, and the output of the DC converters is tightly regulated under all conditions of mains voltage and power output. The result is an amplifier whose power supply is essentially immune to the quality of your incoming AC, which is why these amplifiers accept any mains voltage from 100 to 240VAC without adjustment. In practice, the Universal II does something that very few amplifiers achieve: it disappears. There is no house sound, no editorial voice, no signature warmth or brightness. What you hear is governed entirely by what you feed into it. It is always transparent, always composed, and powerful when the music demands it. At 180 watts into 8 ohms and 360 into 4, with stability into any load greater than 1 ohm, these amplifiers will drive any loudspeaker without complaint. The copper finish with clearcoat is stunning in person and unlike anything else in high-end audio.

Happy to answer any questions. Thanks for your consideration.

Check my stellar feedback and buy with confidence. This listing includes free insured shipping across the CONUS. As this is a passthrough sale that I am brokering on behalf of my client, I prefer to accept payments via PayPal F&F, Venmo Gift, or personal check, but this also gives you the opportunity to attain this at my lowest possible price. Credit card payments are also possible for a 3% convenience charge.

More about the amplifiers:

The NBS Universal II Power Amplifier is a mono power amplifier designed and built by Walter Fields at NBS Audio Cables in the Minneapolis, Minnesota area. NBS (Nothing But Signal) built its reputation on cables before Fields expanded into electronics, applying the same uncompromising engineering philosophy that defined the cable line. The Universal II is derived from the original Universal Power Amplifier, delivering the same design philosophy and performance at a lower power level, smaller physical size, and lower cost. The amplifier uses high-speed switching techniques throughout its entire circuitry. The AC mains input is power factor corrected, achieving a power factor greater than 0.95 at maximum output, which reduces harmonic contamination of the AC mains and improves the efficiency with which commercial electric power is utilized. NBS incorporated power factor correction in their amplifiers for over 14 years, a practice deemed too difficult by most high-end manufacturers. The AC mains input is protected by a magnetic circuit breaker that also serves as the main power switch. The DC converters operate with zero-current transitions, preventing the generation of electromagnetic interference. The output of the DC converters is tightly regulated for all conditions of AC mains voltage and power output, addressing what Fields considered a first-order source of error in amplifier design. The amplifier accepts any AC mains voltage from 100 to 240VAC at 50 or 60Hz without any settings or adjustments, making it truly universal in application. Power output is 180 watts into 8 ohms and 360 watts into 4 ohms. The amplifier is compatible with any load greater than 1 ohm. Frequency range is 4Hz to 35kHz. Voltage gain is 26dB (2V input for rated output, 141mV for 1 watt into 8 ohms). Inputs include one balanced XLR and one single-ended RCA, separately buffered and summed so that both may be used simultaneously if desired. Two sets of binding post speaker outputs are provided to facilitate bi-wiring. A high-performance NBS AC mains cable is provided with each amplifier. The chassis is machined aluminum in a copper finish with clearcoat. Dimensions: 17 x 5.1 x 16 inches (W x H x D, depth excludes connections). Weight: approximately 35 lbs each. Original retail was $18,000/pair.

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