For Sale: Used Audio Research SP20 Tube Preamplifer


Now that Noho Sound is open, co-founder Alex Roy is selling the last best preamplifier he bought before opening our own retail location: his mint condition Audio Research SP-20 tube preamplifier, originally purchased in 2015.

Recently retubed, this Audio Research SP20 tube preamplifier comes with its original remote control and brand new boxes from the factory.

Originally $9,000, we are offering this mint condition unit for $5,500 + tax/shipping from NYC.

Want to hear it? Call or e-mail us for an appointment in lower Manhattan.

Want to buy it now? Here's the Audiogon purchase link.

How good is the Audio Research SP20?

Here's what Stereophile had to say:

"With the neutral, detailed, dynamic, and flexible SP20, Audio Research has hit one out of the park. The company has provided in the SP20 a level of performance of both phono and line stage that would cost almost twice as much to match with ARC separates, when the cost of interconnects is included. ARC has included in the SP20 features derived from their flagship Reference 10 line stage, as well as a first-rate headphone amplifier. I never thought I'd call a $9000 preamp a bargain, but the SP20 is just that."

Anyone buying this is absolutely going to love it.

Fully balanced hybrid preamplifier.
Tube complement: four 6H30 dual triodes.
Frequency response: Line: 2Hz–80kHz, ±3dB.
Phono: 10Hz–20kHz, ±0.1dB of RIAA; 5Hz–80kHz, ±0.4dB.
Headphone: 20Hz–20kHz, ±0.05dB. THD+noise:
Line: <0.003% at 2V RMS, balanced output. Phono: <0.005% at 3V RMS output to Record Out.
Headphone: <0.009% at 1V RMS output. Gain: Line: 13.8dB.
Input impedance: 120k ohms balanced, 60k ohms single-ended.
Phono impedance: 100, 200, 500, 1k or 47k ohms in parallel with 200pF, unbalanced.
Rated outputs: Line: 2V RMS (1V RMS single-ended) into 200k ohms balanced load (maximum balanced output capability is 18V RMS at less than 0.5% THD+N at 1kHz).
Phono: 0.5V RMS into 100k load at Record Out (maximum output capability is 25V RMS). Headphone: 6V RMS maximum into 30–300 ohms.
Output impedance: 500 ohms balanced, 250 ohms single-ended; 1k ohm Record Out, single-ended; <0.05 ohm Headphone, single-ended. Output polarity: non-inverting.
Dimensions: 19" (480mm) W by 5.25" (134mm) H by 16.5" (420mm) D. Weight: 17.8 lbs (7.4kg) net, 27.8 lbs (10.5kg) shipping.

More specs here.

From the original Audio Research press release:

"As a result of the ever-increasing demand for a full-function preamplifier with a level of performance substantially above that of the SP17, we are pleased to introduce the striking new SP20 vacuum-tube preamplifier. Influenced by some of our classic groundbreaking SP preamplifiers but with performance that is only achievable by our best LS- and PH-series designs, the SP20 offers inspirational performance combined with real value.

The look is reminiscent of classic Audio Research components, but is totally modern with a clean, purposeful esthetic. The front panel sports a new 4.3″ LCD touchscreen, with two large rotary knobs on either side. For the first time ever on an Audio Research preamp, there is a ¼” headphone jack, accompanied by three buttons for Power, Mute, and Speaker off.

Those large knobs rotate fully, are optically-coupled and speed sensitive; turn it slowly and the volume will change incrementally; a quick turn one way or the other will raise or lower the volume by a large amount. Also for the first time, the Input selector is on the left, the Volume control is on the right.

Through the touchscreen one can change Inputs, select Stereo or Mono, Mute, adjust Phase, adjust left-right Balance, and adjust the phono input Load (50, 100, 500, 1000 or 47k Ohms). Through a Settings menu, you can customize other items: change input names, adjust gain offset for each input, change volume presets, adjust display brightness (or turn off), and check Tube Hours (or reset). When the tube hour meter reaches 4,000 hours, the Settings icon will turn red to warn the owner it is time to change the tubes.

In addition to the Phono input, there are four other single-ended inputs, two balanced inputs, separate Monitor-in and Record-out, and two pairs of balanced outputs. There is also an RS-232 port, IR-input, 12V trigger, and a 15A IEC connector. The SE4 input can be configured as a home theater pass-through.

The SP20 is fully balanced, pure Class-A with zero feedback. There are seven levels of voltage regulation, a large power supply, and a very low-noise R-core power transformer. Both the line and phono stages feature low-noise JFET inputs and 6H30 (2 per section) outputs. The latest high performance coupling and bypass capacitors are used in both stages. Bandwidth is extraordinary: Line -3dB 0.8Hz – 220kHz, Phono +/- 0.4dB 5Hz—80Hz. Gain of the line section is 13.8dB (BAL), and gain of the phono section is 58dB, so the SP20 can be used with a wide variety of phono cartridges, including moderately low output moving coils.

The headphone output is no mere afterthought, inserted simply as an inexpensive feature to add to the list; it is a low-distortion, high-performance vacuum-tube headphone amplifier designed to comfortably drive a wide impedance range of headphones. The button next to the headphone jack switches off the main (amplifier) outputs for headphone listening, or it switches off the headphone jack for speaker listening.

All of these developments would be for naught if the SP20 did not delight sonically, which it does with ease. The presentation is so relaxed and natural, transparent and solid with great dynamics and impact. Never threadbare, sonic images have texture and a luminous 3-D quality. The SP20 delivers musically, with an ability to effortlessly drive your tube or solid-state amplifier.

Units with Natural front panels, knobs and buttons will start to ship in early September; units with black front panels, knobs and buttons will be available around the middle of October. The retail price will be $9,000."

Want to hear it? Call or e-mail us for an appointment in lower Manhattan.

Want to buy it now? Here's the Audiogon purchase link.