In great condition physically and functionally.
Beautiful sound and aesthetics. Designed and build by the Nakamichi brothers after they sold their holdings in Nakamichi Corporation and started a new company: Mechanical Research Corporation.
80 watts/channel Class A/B; pure Class A up to 35 watts/channel
I have the original packing materials. And I don't mind paying the cost to ship by truck freight, which is probably safe. But I'm still too worried about what the amp might go through. So local pickup would be better. I’m willing to drive up to 2 hours from Greensboro, NC to meet the buyer, if helpful.
UPDATE: I'll be travelling to Philadelphia area by way of either western VA or Washington DC, the week of 3/14 - 3/21, and could meet nearby or along the way.
What follows is from the Manufacturer’s website:
Inputs: Bal: Line inputs A, B, C, andmonitor input
Unbalanced: Line input A and monitor input
700mV / 100k ohms (bal. & unbalanced)
Outputs: Pre Out: 2.3V / 1K ohms (volume at max., bal. & unbalanced)
Rec Out: 700mV 600 ohms (bal. & unbalanced)
Rated Output: 80W per channel continuous sine wave at 8 ohms (maximum without clipping)
Distortion: Less than 0.1% at rated output and load
Frequency Response: 1-50,000 Hz +0, -3dB
Operating Mode: Class AB, BTL mode, maintaining class A operation up to 35W output at rated load
Protection Modes: Output DC, output overcurrent, thermal
Power Requirement: 120 VAC
External Measurements: 460W x 376D x 526H mm (18.1W x 14.8D x 20.7H in.)
Weight: 34kg (74.8lb.)
Forces and Unwanted Currents
Motors and generators are governed by electromagnetic principles. Motors work because current flowing though a conductor produces a magnetic field. This results in forces that act on magnetically permeable material that are in proximity to this current flow. Generators work because if a conductor is set into motion within a magnetic field, current flow is induced.
What does this have to do with amplifiers?
Current-carrying electronic parts generate magnetic fields and forces. Signal-carrying components, including wires and circuit board traces, are caused to vibrate by those forces or by external physical interference, such as sound pressure from the speakers.
In an environment inundated with electromagnetic fields, such motion induces unwanted current in response. It causes distortions that degrade the quality of the audio signal. High-frequency noise transmitted via the power lines is yet another problem that can cause audible artifacts.
Physical fields lie at the root of these phenomena, and combating them requires electromechanical engineering of a very high caliber.
Innovative Heat Sink Design
How can heat sinks affect sound quality?
In conventional amplifiers, heat sinks are large, rectangular structures. If the nearest heat sink fin is some distance from the transistor, the heat travels transverses through the structure. The part of the structure that transfers the heat, then, must be sufficiently thick to ensure efficient conduction.
In the NIRO 1000 Power Engine, each quadrant of the circular heat sink structure is a subassembly that accommodates a push-pull output transistor pair, mounted immediately adjacent to one another to ensure thermal parity. Using a dedicated subassembly for each transistor pair promotes uniform, efficient dissipation across all the fins with no "hot spots." And with four push-pull pairs, the result is an ideal circular structure.
The heat sink mounts via specially designed supports that prevent the transmission of vibration. The mounts are made of a custom gold-plated alloy that is conductive but nonmagnetic. Moreover, close inspection will reveal that the heat sink fins vary in length. Any resonance caused by external excitation, such as high-pressure levels, will thus be diffused over a range of frequencies. Finally, all heat sinks are fitted with a three-millimeter-thick resonance-damping bar.
This highly efficient structure ensures uniform heat distribution, reduces time required to reach stable operating temperatures, and prevents external vibrations from interfering with the audio circuitry.
A Dramatically Different Power Supply
Component layout is the most readily observable difference in the power supplies of NIRO 1000 Amplification Engines. It makes it possible to keep high-power wiring very short. It also prevents wiring for the transformer primary and secondary from physically crossing one another. These goals simply cannot be achieved with traditional chassis layouts, which are conceived in two-dimensional space. The NIRO 1000 three-dimensional implementation is ideal and significantly reduces "noise pollution" generated by the power supply.
The power transformers and chokes generate tremendous vibrational energy, which must be properly dissipated to prevent unwanted interactions with sensitive circuitry. Rather than being affixed by conventional screws or bolts, they are mounted via custom-engineered springs, each with characteristics specifically matched to the weight of the supported component. Almost all of the vibrational energy is converted into harmless thermal energy, i.e., heat. It is an elegant solution that makes an astonishing difference in sound quality.
The inverted mounting of the massive transformers and chokes in the NIRO 1000 Amplification Engines serves two important purposes. First, because they are mounted via the most mechanically stable portion of their casings, the mounting method per se cannot exacerbate unwanted vibration. Second, because transformer and choke wires typically exit the casing via what would normally be the bottom cover, inverted mounting permits much shorter wiring between parts and the rest of the power supply.
The AC input connector block is also "spring-loaded" with an appropriate stabilizing pressure. This dissipates any vibrational energy that might be transmitted via the power cord into the amplifier chassis. A 1mm air gap between the connector block and the surrounding chassis ensures complete isolation from high-frequency interference.
There has never been an amplifier designed with such attention lavished upon so many different aspects of power supply design. This is not an extravagance, for in a very real sense the power supply is the amplifier.
Interference-Free Circuit Layout
A primary design goal in NIRO 1000 Amplification Engines is the elimination of all possible unwanted influences on the audio signal. Toward that end, circuit layout has been optimized to achieve the following important objectives:
- Ensure that none of the input and output wiring physically cross one another within the chassis.
- Preserve a single non-overlapping path from the AC power input to the speaker output.
- Keep as much of the wiring literally as straight as possible, secured by physical guides to prevent unit-to-unit variations.
Printed circuit boards employ free-floating mounts made of specially insulating dampers that isolate them from mechanical and electrical interference. The layout and interconnection of these boards are fundamental components of NIRO design philosophy. In the Power Engines, for example, the input stage board is located near the top of the chassis, the farthest distance possible away from the power supply and servo circuitry ¯ the most likely sources of noise. The line input connector is located at the top of the chassis immediately above the board. The power stage board is located immediately beneath the input stage, so interstage wiring is also as short as possible.
Power is supplied to the input stage via a unidirectional route upward from the rectification stage, through ferrite beads, and through a shielded channel in one corner of the center sleeve. This channel is on the opposite side of the sleeve from the speaker output wiring to maintain the greatest possible separating distance.