Audio Research SP20


SP20 Preamplifier Review




  • Classic Styling
  • Reference Audio Quality
  • Great Feature Set


Company & Product Overview
For over 40 years, Audio Research has produced some of the best audio gear in the world, all out of Minneapolis, MN. Every piece is handmade in the USA and tested to incredibly rigorous standards. And believe it or not, they can actually repair anything they have ever sold, even if it’s 40+ years old. That is saying something!
Audio Research SP20 front
Audio Research SP20 back

Audio Research also has a very special place in the hearts of anyone who has been with Audio Advice long enough to hear the tale of how we got started. Leon, our founder, shares his memories and impressions of the new Audio Research SP20 for us here:

“I can still remember the day  as if it was yesterday, even though now it’s approaching 39 years ago. I had my first full-time job in the audio business, working at Sam Goody at Crabtree Valley Mall in Raleigh. Right out of college and eager to learn as much as possible about audio, I was a sponge for information. (I am still blessed and cursed with this desire, which keeps my house full of new gear but never really buttoned up!).

I was working the sales floor one Friday night when a customer came up to me and asked how I could stand to listen to all this solid state gear. Of course, we struck up a conversation and wound up setting up a listening session at my house the next weekend. He brought over some tube gear I had never listened to, and guess where it came from? Audio Research.

I was immediately seduced with the sound, and I have to say I think that day is what eventually led to me wanting to create Audio Advice. The preamp was an SP3 and the amp was a D75. While the amp was pretty plain looking, the preamp had quite a bit of audio style. Audio Research changed to a pretty different look for their products right after the SP3, but steered back to their roots with the G series.

The other day, I walked into one of our sound rooms and saw we had gotten in the SP20 preamp, and I was immediately drawn right to it!

While it’s gotten the modern updates of a graphical display front panel, the styling is very reminiscent of that SP3 that just blew me away.”

Design and Build Quality

The Audio Research SP20 is a stereo preamp, built to amazing standards. It offers more in the way of input, output, and control flexibility than anything else we have seen from Audio Research.

First of all, it's got a phono stage built in. And at 58db of gain, it’s got enough output for many of the great cartridges on the market, but you can also vary the loading for moving coils right on the front panel! You can also add custom loading should you need something other than the 100, 200, 500, 1000, or 47k the SP20 offers. It sounds fantastic with some of our medium output Soundsmith and Dynavector cartridges.  

The team in Minnesota has also addressed the changing listening habits of many music lovers. In the last 10 years, the headphone market has exploded even more than the vinyl resurgence. There are tons of great headphones on the market these days, but most of the really good ones require a decent headphone amp to get the most out of them. The SP20 is the first ARC preamp EVER to have a built in headphone amp. And this is no afterthought add-on. It’s a vacuum tube amp designed to drive just about any headphone out there. With its ability to throw 6 Volts into any headphone load from 30-300 ohms, it will have no problem driving anything out there.  And right next to the headphone jack is a little button to turn off the main preamp outputs.I tried it with our best HiFiMan and Audeze headphones and was immediately sucked in by the sound. It’s flat out remarkable.

For the last several years, it’s been easy to add an Audio Research stereo preamp to a home theater system. The SP20 is no exception with input 4 having the option of changing it to home theater bypass mode. We’ve also begged Audio Research for years to put an IR (infrared) input on the back. In many of our systems with a smart remote, we would have to stick a little IR emitter on the front panel, which just does not look very good on a great piece of gear. The SP20 sports an IR and RS232 input on the back as well as  a 12v trigger that can be used to automatically turn on their amps or other brands.

Testing 1, 2, 3

We did our listening tests with the SP20 coupled up with Audio Research’s  REF75 power amp and a pair of Vandersteen Quattro Carbon speakers. The source was our favorite NAIM streamer. It did not take long to realize that they have a real winner with the SP20. All everyone wanted to do was keep listening!

One thing that immediately struck everyone was the extremely quiet background. The SP20’s phono and line stage use a combination of low noise solid state JFET’s on the input side and 6H30 tubes on the output, giving you the best of both the solid state and tube worlds. The soundstage is extremely three-dimensional and gives you that classic “you are there” feeling we’ve grown to love from the great ARC products. The bass detail and speed are fantastic as well.

Overall Recommendation

All in all, it sounds great! But you would expect that from a new $9,000 preamp coming from one of the world’s most respected high-performance factories around. What we did not expect was the incredible set of features that make the SP20 a real value.

We have a made in the USA preamp that uses ultra quiet JFET’s and great vacuum tubes that sound amazing. It’s got a fully adjustable phono stage, state of the art headphone amp, and all of the other features a modern day piece of gear should have. You can even make all of the adjustments on the included remote control. We think Audio Research has a real winner with the SP20, and as crazy as it sounds to say a $9,000 piece of gear is a bargain, well, it just is! Heck, some “tube only” headphone amps approach the cost of the SP20.

Already sold? We invite you to talk with your consultant about upgrading your two-channel system to a new level with the SP20.


Classic Styling

Audio Research reached 40 years back to style the new SP20 after their classic SP3 preamp. We love the retro look and departure from their past 40 years of design. It blends modern convenience with retro styling for a wonderful combination.

Reference Audio Quality

The SP20 uses both low noise JFET’s and vacuum tubes to produce some of the most alluring sounds we have ever heard out of a preamp. Just like all great Audio Research products, it will have you listening for hours upon end and wanting more.

Great Feature Set

For the first time ever in an Audio Research preamp, we have a headphone amp as well. Throw in a super flexible phono stage, a home theater bypass, lots of inputs (both balanced and single-ended), and even some automation friendly features. It has more than we have ever seen on a high-end preamp from anyone.

If you have any other questions, please feel free to send us a message or chat with us.