Interviews

Greg Gualtieri: Behind the Gear with Pendulum Audio

Greg's Pendulum Audio has been building pro audio gear since 1998 and building high quality acoustic instrument preamps since 1988. All of the pro audio units he makes feature tubes, Class-A electronics, solid build quality and great sound. Recently he released the Quartet II as a Mercenary Edition, with expanded EQ and new features, plus a cool black finish. Greg, like most folks in this industry, is passionate about what he does and has a strong love of music, and it comes through. -LC

When did you start Pendulum?

I started Pendulum audio in 1988. I went to Columbia University, got my degree in Physics in 1975, and from there I went to work at Bell Laboratories as a research scientist, and during that time also got my masters degree in Solid State Physics from Princeton. During the same period I had been playing guitar in bands and recording and all that kind of stuff, and the same thing that drove my desire to play music was the same kind of thing I saw in doing experimental physics, which was sitting down at a bench designing experiments, building equipment and basically trying to understand how things work. I'd been in bands and had a record deal with a band, and things didn't go well. I decided to do the science thing for thirteen years, and during that time I had been working on lots of audio designs. In 1988 I decided to start Pendulum Audio. Our first product was an acoustic instrument preamp — the first rack mounted acoustic guitar preamp called the HZ-10. It had a four band parametric EQ, and a stereo effect loop. It also had a little phantom-powered box that plugged in the endpin jack of the instrument called a preamp module. That was a little powered head amp so to speak, and it put the preamping of the high impedance pickups — most of these are piezo style pickups that require a 10 megohm input impedance — it put that preamping directly at the instrument without having any batteries involved. It was, if I do say so myself, rather revolutionary, particularly for the acoustic guitar market. We went from that unit in 1988 to the current unit that we're still selling now that came out in 1993: the SPS-1, which is a single rack space, two channel version of the HZ-10, which has three bands of parametric EQ on each channel as well as pan controls for blending the channels in stereo.

How did you move into pro audio?

I went to AES in San Francisco in '98 and I introduced three products all at once, which were the MDP-1 stereo mic pre, the OCL-2 stereo opto compressor and the 6386 mu compressor. Those are designs that have arisen out of equipment that I had built and used in my own personal studio. The MDP-1 is a Class-A, all tube design with a transformerless output stage, with a great deal of headroom. It can do +35d Buinto10 kohms. What I was shooting for with that design was to try and make a very big, open-sounding mic pre, which has a certain amount of tube coloration if you're looking for coloration, but not coloration associated with the artifacts you normally find in vintage equipment. Just that certain openness and detail and honesty in the midrange, which to my mind is what tubes are best at doing.

As far as your compressors go, you mentioned in an early conversation that you were going for the Fairchild "Holy Grail" sound. Would you say that is still the case?

I've been building compressors for a long time — many of the opto and mu varieties — and I was always a big fan of the sound of The Beatles' records and other records that I learned later had been processed through the Fairchild. There was something magical to my ears in the way that it compressed, the character of the compression and the sound that it gave those records — to me the sound of rock n' roll is compression, tape saturation and sometimes equipment saturation. So I've long been building compressors with that idea in mind, and when I designed the 6386 I had learned which tube they had used in the Fairchild and began building a mu compressor around that, and learned that the magic was in that compression profile that was unique to that tube. What I did was basically give the compressor my own wrinkle on the Fairchild sound in that rather than using a vintage circuit topology with an output transformer, I decided to make it transformerless Class-A just to make it a bit more hi-fi sounding but still have that same character of compression. The ES-8 is a very similar unit but uses a different tube, which is easier to find these days.

So is the 6386 a more aggressive sounding compressor? Or are you trying to make the ES-8 sound identical to the 6386?

MORE INTERVIEWS

Hidden Musics
INTERVIEWS · ISSUE #175 · Sep 2026

Hidden Musics

By Ian Brennan

By 2014, I'd already been transitioning for more than five years from working in traditional studios to almost exclusively doing field recordings overseas. As a result, I'd had some success with groups like Tinariwen, Malawi Mouse Boys, and The Good Ones. At that point, the...

Yves Jarvis
INTERVIEWS · ISSUE #175 · Sep 2026

Yves Jarvis

By Geoff Stanfield

Yves Jarvis is the moniker of Canadian musician Jean-Sébastien Yves Jarvis. His latest release, All Cylinders, won Canada’s Polaris Music Prize for best album of 2025, a record on which Jarvis wrote and performed all of the 16 tracks. Made entirely using Audacity and a half-broken...

Joe Boles
INTERVIEWS · ISSUE #175 · Sep 2026

Joe Boles Seattle Recording Pioneer

By Alex Kostelnik

In the mid-1950s, Seattle was host to the little-known music recording legacy of Jay F. "Joe" Boles. A fraction of his discography includes The Ventures, The Wailers, Cab Calloway, Big Jay McNeely, Buck Owens, The Fleetwoods, Robert "Bumps" Blackwell, Ella...

  Rostam Batmanglij
INTERVIEWS · ISSUE #175 · Sep 2026

Rostam Batmanglij Sonic Cinema

By Sam Retzer

Ever since Rostam Batmanglij burst onto the scene as a founding member of Vampire Weekend, he’s been known for his penchant for baroque and leftfield sounds in pop-leaning indie music. Fresh out of college, he handled production for the first three Vampire Weekend albums (Vampire...

Melina Duterte
INTERVIEWS · ISSUE #175 · Sep 2026

Melina Duterte Sharing Curiosity

By Danielle Goldsmith

Melina Duterte began recording her own music armed with little more than a laptop, a budget mic, and a fascination with how records are made. As Jay Som, she crafted a distinctive sound defined by textural, layered guitars, and soft, intimate vocals. Since then, Duterte has expanded...

Oli Jacobs
INTERVIEWS · ISSUE #175 · Sep 2026

Oli Jacobs Friends & Commitment

By Larry Crane

A graduate of the Tonmeister course, a former Head Engineer at Peter Gabriel’s Real World Studios [Tape Op#63], and now an in-demand mixer, engineer, and collaborator with Jack Antonoff and Laura Sisk [#135], Oli Jacobs has had a heck of a career path. He’s worked on records for artists...