Audio Research Reference 5SE Tube Preamplifier

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General:
The Reference 5 SE benefits from several advancements that Audio Research developed for their cost-no-object, limited-edition Anniversary Reference preamplifier ($24,995), including two readily visible changes from the Ref 5.

First, the 5 SE's front panel mirrors that of the Anniversary: the buttons are now tidy, round, metal, and set directly into the faceplate, rather than the Ref 5's square, recessed plastic buttons. Added on the inside, to the left, is a vertically mounted circuit board, stuffed to the gills with capacitors to nearly double the Ref 5's already massive energy storage.

Other changes include new Teflon and hybrid coupling and bypass capacitors, and changes in the internal wiring.

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:
One single owner since new and has been well cared for.

Amplifier Recommendations:
Both solid state and tube should pair well with this unit. A good ARC match would be a REF160, 250SE, 150, or 75.

Connections:
7 Sets of inputs and 3 sets of outputs, all single-ended AND balanced. 20A removable power cord.

General Sound:
Warm tube sound with great harmonics and laid back delivery. Super neutral and clean sounding with little to no sonic signature.

Cosmetic Condition:
We rated this a 7 with light signs of use and wear. See our detailed rating description here.

Working Condition and Technical Notes:
Working properly, fully tested in our lab and listening room.

Included:
Unit as pictured, brand new remote control from Audio Research, and a 20A power cord.

Packing:
Will be packed in the original manufacturers box.

Original MSRP:
$13,000

Specs:
FREQUENCY RESPONSE
REF55 SE: +0-3dB, 0.5Hz to 200kHz at rated output (Balanced, 200k ohms load).

DISTORTION (THD)
Less than .01% at 2V RMS Balanced output.

NOISE & HUM
1.7µV RMS residual IHF weighted balanced equivalent input noise with volume at 1 (109dB below 2V RMS output.)

GAIN
REF5 SE: Main output: 12dB Balanced output, 6dB SE output. Tape output: 0dB. (Processor input: 0dB SE output).

INPUT IMPEDANCE
120K ohms Balanced, 60K ohms SE

OUTPUT IMPEDANCE
600 ohms Balanced, 300 ohms SE main (2), 20K ohms minimum load and 2000pF maximum capacitance.

OUTPUT POLARITY
Non-inverting

MAXIMUM INPUTS
20V RMS maximum Balanced, 10V RMS SE.

RATED OUTPUTS
2V RMS (1V RMS SE) into 200K ohm balanced load (maximum balanced output capability is 30V RMS at less than 0.5% THD at 1kHz).

POWER SUPPLIES
Electronically regulated low and high voltage supplies. Automatic 40 sec. warm-up/brown-out mute. Line regulation better than .01%.

TUBE COMPLEMENT
(4) 6H30P, plus (1 each) 6550C and 6H30P in power supply.

POWER REQUIREMENTS
100-135VAC 60Hz (200-270VAC 50/60Hz) 130 watts. Standby: 2 watts.

OTHER
Inputs (7): CD, TUNER, VIDEO, PHONO, AUX1, AUX2, PROCESSOR. (XLR and RCA connectors). Outputs (3): 2 main, 1 tape (XLR and RCA connectors). Crosstalk: -80dB or better at 1kHz and 10kHz. Controls: Volume (104 steps), Select Input. Push Buttons: Power, Proc, BAL/SE, Mono, Invert, Mute.

Dimensions and Weight:
19" (485mm) W by 7" (178mm) H by 15.5" (394mm) D. Handles extend 1.5" (38mm) forward of front panel. Weight: 30.4 lbs (13.9kg) net, 41.6 lbs (19kg) shipping.

Age:
This model was available in the mid 2010's

Reviews:
Stereophile by Brian Damkroger

Link to manual :
Audio Research Reference 5SE Tube Preamplifier (REF5SE)

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best

Kimber Kable - Phono Interconnects - Better

Kimber Kable - Flagship Tonearm Interconnects - Best

Kimber Kable - BALANCED XLR Connectors - Better

Kimber Kable - BALANCED XLR Connectors - Best

Kimber Kable - Power Cords - Better

Kimber Kable - Power Cords - Best

The SkyFi Testing Process for Preamplifiers:
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 the PCBs for discoloration from resistors or transistors that may have been running hot. 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.

When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope. We then switch to a 1KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment. Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.

We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected. If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.