AUDIO RESEARCH REFERENCE 160M (REF 160M) - MOST BEAUTIFUL AMPLIFIER EVER MADE

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General:
Quite possibly the most beautiful amplifiers ever designed. 

The meters look like they're floating in the air, and the tubes are visible right behind them! 

Utilizing KT150 tubes, this is about as modern and detailed sounding a tube amp will get. 

Both amps look practically new with JUST 282 hours on the tubes which is under two weeks! And we know such an exact figure as ARC displays tube hours right on the rear. We wish more tube amplifiers had this feature, as it's one of the most asked questions. 

Built-in auto bias means you never have to fuss around with the tubes. And tube rollers can play around with KT88, KT120, and 6550's without making any adjustments. 

And this listing comes to you complete with all of the original Audio Research packaging (which we just ordered fresh).

More on these beauties from Audio Research:
After two years in development, the new Reference 160M (REF160M) Monoblock Power Amplifier is built like no other, looks like no other, and sounds like no other amplifier that you have ever heard, but it is unmistakably Audio Research. It features a refined audio topology with fewer and better components in the signal-path than in previous designs, switchable Ultralinear/Triode operation, proprietary auto-bias, output tube monitoring and protection, an advanced power meter, and much more. This array of features has never been offered before in an Audio Research amplifier.

The designers at Audio Research wanted to create a new style that would complement the look of the REF6 preamp while also featuring a GhostMeter™ that allows a view of the glowing KT150 vacuum tubes. While this GhostMeter™ allows you to see the output tubes, it also incorporates an innovative dual-layer construction with distinctively etched markings that create an integrated power meter. The power meter’s output-level markings illuminate via hidden LEDs, and the illumination brightness is adjustable. The REF160M includes a sculpted cover with an integrated fan to cool the heat generated by the four (4) KT150 output tubes and two (2) 6H30 driver tubes. Solid-state power regulation was chosen to provide increased efficiency, stability, and reliability. The power supply stage uses a newly developed High Energy Capacity Transformer and a hefty bulk storage-capacity network to provide extremely high current on demand for transient peaks and intense dynamics, as well as for prodigious bass depth and authority.

It is understood that the best path is the shortest path. Audio Research engineers created a new audio circuit topology with the shortest signal path and the fewest components. Those components are not only the best available, many are custom made for Audio Research. Incorporating these quality components is a special 4-layer circuit board that lowers the noise floor to unprecedented levels, and a design which was previously reserved for use in our preamplifiers. The result is a new benchmark in musicality in every criterion of sound quality.

The REF160M also features a proprietary auto-bias circuit that works with various tubes types, including 6550, KT88, and KT120, in addition to the supplied KT150 and works constantly to maintain precise bias of the output tubes, while also adjusting for tube wear. There is no need to check or adjust bias ever again.

The new REF160M breaks new ground sonically, aesthetically and operationally, and will be available in Natural (Silver) or Black finishes.

Brand Background:
Audio Research continues its dedication to unparalleled musical expression and crafting components of the highest quality and lasting value for its customers. Our long-term dedication to service is peerless in this industry (Audio Research, with few exceptions, can repair anything ever produced during its entire history). We continue to seek out new and exciting ways to make music more real and more enjoyable. More than just a name or a marketing tool, Audio Research has come to represent exceptional performance and long-term value. Experience Audio Research – experience High Definition®.

Ownership:
Single Owner

Amplifier Recommendations:
N/A

Connections:
XLR and RCA inputs
20 Amp power cord
5 way speaker binding posts
12 V 1/4" trigger

General Sound:
Smooth, uncolored, undistorted natural and clean

Working Condition:
Working perfectly and tested in our lab and listening room.

Included:
Just the unit and power cord.

Packing:
Original Manufacturers Packing

Original MSRP:
$38,000.00

Specs:
POWER OUTPUT
140 watts continuous from 20Hz to 20kHz. 1kHz total harmonic distortion typically 1% at 140 watts, below 0.04% at 1 watt. (Note that actual power output is dependent upon both line voltage and “condition” i.e.: if power line has high distortion, maximum power will be affected adversely, although from a listening standpoint this is not critical).

POWER BANDWIDTH
(-3dB Points) 5Hz to 70kHz.

FREQUENCY RESPONSE
(-3dB points at 1 watt) 0.5Hz to 110kHz.

INPUT SENSITIVITY
2.4V RMS Balanced for rated output. (25.5 dB gain into 8 ohms).

NPUT IMPEDANCE
200 k ohms Balanced.

OUTPUT POLARITY
Non-inverting. Balanced input pin 2+ (IEC-268).

OUTPUT TAPS
16 ohms, 8 ohms, 4 ohms.

OUTPUT REGULATION
Approximately 0.6dB 16 OHM LOAD TO OPEN CIRCUIT (Damping factor
approximately 14).

OVERALL NEGATIVE FEEDBACK
14dB SLEW RATE: 13 volts/microsecond RISE TIME: 2.0 microseconds.

POWER REQUIREMENTS
105-130VAC 60Hz (210-250VAC 50Hz) 400 watts at rated output, 700 watts maximum, 260 watts at “idle”, 1 watt off.

TUBES REQUIRED
2 matched pair KT150 (Power output V1-4); 2 6H30 (Gain stage V5 and V6).

Dimensions:
Width 17.25” (43.8 cm)
Height 10” (25.4 cm)
Depth 18.5” (47 cm)
Handles Extended 19.25” (48.9 cm)

Weight:
120 lbs.

Link to Manual:
Click Here

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Speaker Cables - Better

Kimber Summit Series Monocle XL Speaker Cables (PAIR) - Best

Kimber Summit Series BiFocal XL Bi-Wire Speaker Cables (PAIR) - Best If Applicable 

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect resistors and other passive components for signs of overheating. If tube arcing has occurred in the past we can usually spot discoloration on the output tube sockets. On vintage units we often spot check select capacitors for value and ESR.

If the amplifier passes visual inspection, we move on to a full test of all of the tubes. We use an Amplitrex AT-1000 Tube Tester which is capable of testing both emission and Gm with a high degree of accuracy. We document the results of each tube and replace any weak or suspect tubes before proceeding. When we power on tube amplifiers for the first time we usually use a variac and current limited AC supply and slowly raise the voltage up to nominal mains level while monitoring plate, screen, filament, and negative bias supply voltages where applicable. If everything is in order we feed a low level test signal into the amplifier’s input and monitor its output on an oscilloscope across an 8 ohm dummy load. At this point we are just looking to verify basic function and confirm that the output transformers are not damaged. Once we have verified that the amplifier is safe to operate, we connected it to full mains power. For fixed bias amps we set the bias to manufacturer spec. For cathode biased amps we monitor the plate to cathode voltage to determine if the output tubes are operating in a safe range. Once the output section is verified we move onto bench evaluation.

We start by feeding the input of the amplifier with a low level 1KHz test signal, slowly increase its amplitude while monitoring the amplifier’s output on an oscilloscope for signs of noise, clipping, distortion, or improper channel balance. We continue increasing the signal level until the amplifier reaches clipping. At this point we take an output power measurement and compare it to the spec sheet of the amplifier to verify proper performance. We finish off the bench evaluation with a 1KHz square wave check and a 20Hz to 20KHz sine sweep to assess the amplifier’s frequency response characteristics. This battery of tests will usually reveal if the amplifier has any issues that need further attention.

Before the device leaves the bench, we perform a listening test with actual music using a variety of preferred test tracks. Our benches are outfitted with familiar monitor speakers which help us identify inconsistencies that will not always show up on our test gear. The main things that we are listening for are hum or noise with no signal present, proper center image, clicks, pops, or any other obvious undesirable audio characteristics.

If the unit passes all of these tests it is moved to our long term testing rig where we simulate real word operating conditions for 6-8 hours. For tube amps we like to run this test at least twice. This allows us to monitor the unit for signs of thermal runaway or intermittent issues that only crop up when it has fully come up to temperature. We find this step to be essential, especially for vintage units.