Gramophone Dreams

One of the many pleasures of the Burning Amp Festival is that everyone goes home with free gifts worth more than the cost of admission. Pass had made up a small batch of H2 generators, stuffed and calibrated, to hand out at the Festival. He even included a wall-wart power supply. I got one for testing.

Siegfried Linkwitz
At Burning Amp, Nelson Pass and his friend Laurie Fincham delivered quiet memorials to loudspeaker designer Siegfried Linkwitz (1935–2018), who died September 11. Fincham read a poem he'd written, "Siegfried's Saga."

I'd known Linkwitz a little, and loved talking speakers with him, but nothing I can say here could match Michael Fremer's Pulitzer Prize–quality tribute in the September 2018 "Analog Corner."

I almost died
The address on the invitation read "Sea Ranch." I figured Nelson Pass must live on some scenic but long-defunct Hollywood movie set like Big Sky Ranch (footnote 3). But Sea Ranch is actually a planned, unincorporated community, established in 1964, that is the polar opposite of our East Coast dystopian sprawl. Though every inch of it looks wild and completely natural, it was all designed by a landscape architect. The houses have no paint and no eaves. There are no streetlights or stoplights, no utility poles or stores or gas stations. But there are deer and snakes and dogs and jackrabbits everywhere. Best of all, there are seals galore and whales offshore. A herd of sheep keep the grass cut low. This is where Nelson, Jill, and Jack live—where they stay near to the oceanic life force.

The exoticness of my Sea Ranch experience was intensified in the three hours it took to get there from Fisherman's Wharf. Approaching Sea Ranch along California's otherworldly, superscenic, supernarrow, death-at-every-curve Coastal Route 1 is dangerous: hairpin curves, high cliffs, and no guardrails. It's even more dangerous if you're driving with Bryan Stanton, who fancies himself a sport-racer complete with driving gloves, lead foot, and no sleep.

Pass had warned me: "It's not as bad driving up [north], because at least you're on the inside lane. It's going back [south] where you can die. You're on the outside lane, and one mistake—then total silence."

Stanton tried to calm me: "Don't worry, Herb—I am in control!"

I cried, I pleaded, I prayed aloud. It was night-dark with thick fog and sheets of rain. Giant out-of-control trucks careened toward us, their headlights on high. Stanton was doubling the speed limit. "We're gonna die!" I sobbed. He giggled, then sneered a dastardly sneer.

The next morning was bright, with light drizzle. Stirling Moss had told me not to wake him before 11am, so around 10am I walked from the guest house to the Nelson-Jill-Jack house. The first thing Pass showed me was his workbench. The first thing I stared at were the holes in the yellow sponges he uses to clean the tips of his three soldering irons. I saw a heat gun, and bits of circuit scattered everywhere. That's all I remember now, except that Nelson Pass seems to own nothing fancy. His living quarters are beautiful but conspicuously humble. His most notable possessions, besides a handsome dog and a spectacular ocean view, are hundreds of thousands of transistors.

Pass's work-study-listening room was filled with LPs, a Technics SL-1200 turntable, and stereo pairs of various full-range drivers mounted in a variety of birch-ply cabinets. His main studio speakers were vintage Tannoy 15" coaxials mounted in rear-loaded-horn cabinets. We listened to a two-way, open-baffle design featuring a Cube Audio 8" F8 Magus full-range driver powered by Pass's latest First Watt amplifier, the SIT-3. Below and behind the Magus's vertical baffle, mounted face-down on a small horizontal baffle about 5" above the floor, was a slot-loaded 15" Eminence woofer. The woofer was separated from the wide-open full-range driver by an LX Mini active crossover and driven by a First Watt F7 amplifier.

Confession: As much as I enjoy BBC minimonitors and Western Electric horns, I've always aspired to own a system exactly like Nelson Pass's open-baffle design. Problem is, I've experimented a lot with full-range drivers—including Western Electric 755As, Lowthers, Jordans, Fostexes, etc.—but had never found one I could live with. Until I visited Sea Ranch.

Immediately, those Pass creations made every two-way-with-dome-tweeter design sound closed-in. They made Quad 57s sound repressed. The Cube Audio F8 Maguses' treated-paper cones had an audible sound character (what driver doesn't?) but that character was extremely subtle, and distinctly all-natural. The Cube drivers were playing raw, with no dulling crossover between the amp terminals and speaker motor. No part of the reproduction process was hidden or suppressed. Imagine fast, direct, exceptionally see-through. Music was vivid and lively, but never too much so. Nelson Pass was getting more life and transparency from the Cube F8 Maguses and his own SIT-3 than I got from the same amp and any of the speakers in my home collection.

The sun beamed from the window behind my chair. I was listening, dreaming, feeling quite pleased to be in Nelson Pass's listening studio with wolf-eyed Jack lying on the floor before me, when Bryan Stanton arrived. "Nelson," he said, "what will Herb's readers think when they see your RadioShack wires?" I smiled. Pass smirked, then chuckled. "They'll think I don't want anyone else taking credit for my achievements."

Back in the main house, we sat on leather recliners, drank wine, and listened to music through Pass's smooth-as-silk Pass Labs big rig—while keeping one eye peeled for whales on the sun-sparkled ocean. (Stanton and Pass saw two or three; I was too busy petting Jack to notice.)

Home again
Before leaving for the left coast, I'd been midway through my review of the Nelson Pass–designed First Watt SIT-3 stereo amplifier, but already I knew it was doing a just-right/not-too-much job with second-harmonics: It delivered deep, airy spaces, dense images, and prize-winning timbres, but it was never thick or fuzzy. I therefore waited to try out Pass's H2 Harmonic Generator until after I'd installed a different Pass design, one with a more mainstream sound and lower amounts of second-harmonic distortion: the Pass Laboratories XA25.

With the H2 inserted between my preamp and the XA25, the system's sound changed noticeably. At first, I couldn't say what had changed—then I remembered that inserting this extra, unity-gain, phase-inverting stage had inverted my system's absolute phase. So I listened for a while to the effects of positive phase second-harmonic distortion. Compared to normal phase and no H2, the sound seemed drier and strangely duller, but also more detailed. Percussion was more percussive. Guitar strings felt more tightly strung. Flutes sounded sharper but less harmonically expansive.

Nelson Pass had said that H2 experiments should be conducted with "simple" musical program. He warned: with complex program, excessive second harmonic can do more harm than good.

Honoring his wish, I pulled out one of my favorite Alan Lomax recordings: Southern Journey, Volume 3: 61 Highway Mississippi—Delta Country Blues, Spirituals, Work Songs & Dance Music (CD, Rounder 1703), recorded with a single microphone. What Pass had said was true: singers and instruments seemed closer to that mike than before.

When I reversed my speaker leads, creating negative-phase second-harmonic distortion (still at the H2's original setting), everything got gentler, warmer, more distant, and more colorful—but not necessarily better. I missed the punch, but welcomed what I perceived as enhanced overtones and more natural-sounding voices.

Next, hoping I understood how the H2 worked, I used its little trim pot to lower the regulated voltage across the JFET's drain load resistor, from 15.6 to 15.1VDC. This raised the distortion and took the abovementioned negative-phase second harmonic even further. Crispness was further reduced. Music was still presented in a pleasurable manner—but I definitely liked it better at the higher voltage.

After "Louisiana," by Henry Ratcliff, and Mississippi Fred McDowell's "61 Highway Blues," I couldn't stop myself—I turned the JFET's drain voltage up to 16VDC. According to Pass, this should audibly reduce distortion. All I noticed was a rather unpleasant loss of tone color and spatial content.

When I removed the H2 from the circuit, my record-playing life immediately improved: that weird, dull feeling disappeared, replaced by the XA25 amplifier's signature transparency.

Gratitude
Hanging with Nelson Pass reminded me that the reproduction of recorded music is truly an entertaining illusion: "not dialysis!"

I've been following the work of Nelson Pass since his days with Threshold, and am forever a fan of his Aleph series amplifiers. I'm currently under the spell of his First Watt explorations. But now that I've sat and walked with him, I think I understand a little of why he's still searching for fresh possibilities, speculating on what we actually know vs what we think we know, and experimenting with amplifier circuits that lesser designers would dismiss as untenable. My hat is off and I am facing West.

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Footnote 3: Big Sky Ranch is in Simi Valley, California. It was used for the filming of such TV shows as Gunsmoke, Bonanza, and Little House on the Prairie.