Audio Research Corporation began in 1970 with the goal of producing vacuum-tube preamplifiers and amplifiers, and have long been regarded as the makers of some of the finest high-end tube electronics in the world. The company's original products are still 100 percent supported by the factory and command significant resale values - as well as a near cult-like following. Fast-forward forty years to Audio Research's 40th Anniversary and ask yourself: what would you do to commemorate the occasion? Well, if you're Audio Research, you build something worthy of being called an Anniversary Edition, and given their outstanding reputation for building world-class preamplifiers, it was logical that this anniversary edition would be one. The Audio Research 40th Anniversary Edition Reference preamplifier is this commemorative piece. Retailing for a cool $25,000 and only in production for one calendar year, the Audio Research's 40th is a piece of audio jewelry few will ever own but all will likely lust after for years to come.
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The Anniversary Edition preamplifier is built beyond anything ever produced by Audio Research. Featuring a dual chassis design with one for the power supplies and one for the audio section, the two units are connected by two large umbilical cords and the power supply is connected with a 20 Amp IEC plug. The preamplifier has twice the power supply of any previous ARC preamplifier, and frankly more than many large amplifiers. The power supplies are completely separate for each channel, featuring separate low and high voltage transformers as well as vacuum-tube regulation (6550C, 6H30). The massive power supplies and power reserves ensure near limitless headroom and dynamics.
The Anniversary Edition's analog section is also isolated to maximize audio quality; featuring an all-tube, pure Class-A triode circuit that possesses zero feedback. A first for any tube preamplifier, the Anniversary Edition's audio gain circuit is a dual-mono design featuring eight 6H30 triode tubes, four for each channel. Further proof that the Anniversary Edition is unlike any preamp you've seen or heard, especially when it comes to ARC's attention to detail and performance, is its use of custom Teflon coupling capacitors each tipping the scales at more than two pounds.
The 40th Anniversary Reference preamplifier offers six stereo inputs and a dedicated home theater bypass for integration into 'hybrid' or dual use systems with two outputs and a tape out as well. All inputs and outputs are either single-ended or balanced. The analog unit is almost identical to their Reference 5 preamp except the buttons across the bottom of the faceplate are now surface mounted rather than recessed. A large central green OLED display that can be turned off for peak performance conveys all the information one could need, while the two dials on the left and right control volume and input. The buttons across the bottom cover mute, power, phase, processor or home theater bypass mode, Balanced or single-ended and mono.
Both the power and analog sections measure 19 inches wide, seven inches tall and 15.5 deep. The audio chassis weighs 29 pounds whereas the power supply chassis is 39 pounds, bringing the total system weight to 68 pounds. It's a serious piece, especially considering it's a two-channel preamp.
The 40th Anniversary Reference Preamplifier comes packed like the jewel it is. Both chassis come double boxed, with the inner box surrounded by a layer of dense foam. Inside, each piece is wrapped and padded for added security. All the necessary hardware is, of course, included. The tubes are wrapped and packaged in dense foam, and are numbered to perfectly mate to your specific preamplifier and additional tubes are provided as spares. The modest plastic remote, power cord, two umbilical cords, Philips head screwdriver, cotton gloves for handling the tubes and appropriately short manual are all included.
Once you unpack the two pieces, you will need to remove the tops of both with the included Philips head screwdriver and place the tubes into the appropriately number sockets. Place the units on your rack, connect the two umbilical cords which are about four feet allowing for a decent amount of placement options, make your connections and plug the unit in. Audio Research has large warnings all over the pieces to never disconnect the umbilical cords with the power supply plugged in - so don't do it.
Audio Research has all critical components custom engineered and manufactured exclusively for them, and supply is tough to get at this level. When I finally got my unit, I wanted so desperately to hear it that I quickly unboxed both pieces, installed the tubes and cleared space on my rack, both by removing the Audio Research Reference 5 preamplifier it was replacing and re-spacing the shelving to allow the power supply chassis plenty of room to breathe. I connected the 40th Anniversary Edition between my Classe-SSP-800 AV Preamp and Krell Evo 403 amp feeding Wilson Sasha W/P speakers and also ran an Oppo BDP-95 and my trusted EMM Labs TSD1 and DAC2 SE combo, both on balanced inputs. All wiring was with Transparent Reference XL for both speaker and audio cables.
I know that break-in is required, and for a piece with capacitors the size of my fists I expected a prolonged break-in. My Ref 5 continued to improve for the first 650 hours. At hour zero I knew it could do better. I ran the preamp for several hours a day and over the first few hundred hours the sound continued to open up and become more spacious and the soundstage deeper. At around 350 hours the sound was really impressive with an ability to pull you into the music and make you feel that you're among the musicians rather than just listening to them.
Now it was time for some critical listening.
I listen to a lot of blues and a recent favorite disc of mine is Son House's Original Delta Blues (Sony). This album is very simple musically but also very powerful. The lone guitar in "Death Letter" had amazing detail and attack, filling the room yet staying well placed. You could hear every detail of the plucking of the strings and feel the texture of the wood of the guitar; it was truly inspiring to hear. The vocals were so clear it felt as though Son House was in my room singing in front of me. "Grinnin' In Your Face" brought chills to my spine with the accuracy of the vocals and the reality portrayed by the hand clapping, the only accompaniment to Son's vocals in the song. The detail was such that you could tell exactly how each hit landed. The slide guitar and harmonica on "Levee Camp Moan" were completely true to life and had amazing weight and depth to them.
Read more about the performance of the Audio Research 40th Anniversary Reference Preamp on Page 2.