Friday, February 25, 2011

A Visit with the Audio Research SP-7


Audio Research is a company that is known, along with Conrad-Johnson, for keeping the vacuum tube flame alive during the 70s and 80s. Back then there weren't many competitors in the lonely market of new audiophile tube gear - in the United States you had to go vintage, which many of my friends did, or spend the big money and buy an ARC or C-J piece. All of that has changed with the sudden rush of the Internet-90s and the increasing popularity of tube gear.

The Audio Research SP-7 was an odd duck - it's solid-state and is historically sandwiched between the famed SP-6 and SP-8 tubed preamplifiers. Audio Research was looking to expand their market share and offer something to the solid-state aficionado. But it would appear that this move did not have much success as their solid-state gear back then never sold in great numbers. And that is hardly surprising considering the near-religious mania of many vacuum tube listeners. It's either tubes or the highway - I know since I used to be in that camp myself. With Threshold and the Audio Sector phono stage, my views have softened in this matter since a good design is still good no matter what the technology is.

So how good is the Audio Research SP-7? Let's find out.

We've been remodeling our living room with a new, more modern look. I decided some different gear for my second system was in order - something that would fit the blond Ikea Expedit shelves I use to store my records. I selected an Audio Research SP-7 available on Audiogon almost solely on the looks and their renowned reliability. It didn't hurt that I've always admired my friend's SP-8.

The SP-7 is full-function preamplifier with a moving-magnet phono stage, tape outs, heavy duty case and controls that inspire confidence with their quality movement. Inside there are a bevy of capacitors and transistors on a thick PCB, all supporting the 'mysterious' potted Audio Research Analogue Modules. These are rumored to be op-amps made from discrete components, but I haven't found any conclusive evidence yet.

Hooking up the SP-7 to my second system, I found the sound to be much better than the Adcom GTP-400 or the Dynaco PAT-4. Bass with the KEF Q60s seemed to go lower and the overall sound was very clean, detailed and fast. Definitely not tubey at all but the sound was way less grainy than the other SS gear. It was a really good match with my Dual turntable.

On the main rig, I am using a low-output Denon DL-103R and was not able to check out the phono stage on the SP-7. That was handled by the Audio Sector phono stage while the SP-7 did linestage duties, temporarily replacing my beloved Threshold FET-10/HL. The FETs in the Threshold give a darker, almost tubey sound while the ARC had a brighter, more forward effect. The SP-7's treble was still good with no solid-state etchiness. The midrange was very detailed too. Depth and soundstaging was slightly more squashed than the Threshold while the bass for both was pretty much on par. In the end I was surprised how good the Audio Research SP-7 sounded considering the rather negative press these pieces get.

As far as looks and functionality goes, I couldn't ask for much more in this price segment. To further the looks of my second system, I'll be on the hunt for a matching Audio Research solid-state amplifier, so stay tuned.

Second System:
Dynaco PAT-4 refurbished or Adcom GTP-400 tuner preamplifier

Dynaco ST-80 refurbished or Adcom GFA-535
Dual CS-5000 turntable with Audio-Technica AT95E cartridge
Pioneer DVD-V7400 DVD player
KEF Q60 speakers

various budget cables

Main System:
Threshold FET-10HL
linestage
Audio Sector Phono Stage
Threshold S500 amplifier
VPI HW19 MkIII turntable - Rega RB300 with Incognito wiring - Denon DL-103R
Magnepan 1.6/QR speakers with Sound Anchor Stands
Kimber 4PR/8PR Bi-wire with banana jacks
Cardas Cross and Cardas Quadlink 5C interconnects

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