Gramophone Dreams #42: Sunvalley Audio SV-EQ1616D phono equalizer

The 1980s was a decade when I needed three jobs to support my wife, infant daughter, and octogenarian dad. My primary job was to make and sell art, and I’m sure you know how that can go. Between exhibitions, I was forced to do construction work and to find, repair, and resell old tube amplifiers.

What I remember most from that period was how much I loved Phil Rizzuto and Yankee baseball on AM radio and how often I burned myself on the soldering iron.

Except for each brand’s unique wiring layout, chassis construction, and finish, the tube amps I repaired were mostly boring. Circuit-wise and sonics-wise, they were quite similar to each other and generally unremarkable. After fixing and auditioning scores of these crusty boxes, I realized that the better-sounding ones, the ones that were neither slow, dull, nor screechy, employed large, high-quality transformers, the simplest circuits, and tube rectifiers. The more tube amps I repaired, the less I admired mainstream (1950s and 1960s) home audio and the more I admired professional sound-reinforcement gear from companies like Altec, Ampex, IPC, and Bogen.

What really bugged me were the phono preamps of the time. Almost universally, they sounded opaque and undynamic. The only one I thought was all right was the Dynaco PAS-3X’s phono stage, which, with tweaks and modifications, anchored my personal hi-fi until I couldn’t stand it any longer.

At that point, as an experiment, I scratch-built RCA’s “Preamplifier for Magnetic Phonograph Pickup With RIAA Equalization” to see if I could do better than the Dynaco or Marantz preamps that passed through my workshop. The schematic for this passively equalized phono preamp was in the back of every RCA tube manual, and the circuit fit easily in a $5 aluminum Bud box.

My knocked-together phono stage turned out livelier and more transparent than the feedback-equalized counterpart in the Marantz 7C preamplifier. Why did my preamp sound better than Sid Smith’s? I speculated that it was because I had used a higher current, 5U4-tube–rectified power supply designed for RCA’s 30 watt “High-Fidelity Audio Amplifier,” which also had a schematic in the back of the RCA tube manual. (The Marantz 7C used a solid-state bridge rectifier.)

Encouraged by these results, I replaced the supply’s 50 ohm pi-filter resistor with a low-impedance choke. The preamp opened up and made me quite happy. Eventually, I fabricated a separate chassis for the power supply and connected it to my RIAA circuit with a detachable umbilical cord. This allowed me to audition a variety of home-brew and military-surplus +250VDC power supplies.

I was astonished by how much difference power supplies made—how different power-supply topologies changed my system’s sound. I realized then that how one makes those stable, quiet volts could be the biggest factor in amplifier design, and that low-noise, accurate RIAA equalization is far from the most serious issue affecting phono preamplifier sound quality.

I built this RCA RIAA stage, and many others, just before digital went mainstream.

Back then, I could never have imagined that now, almost 40 years into the digital era, there would be countless newly manufactured phono preamplification devices for audiophiles to choose from, or that phono-preamp circuit innovation would continue, bringing alternative topologies like LCR and LR equalization and current-mode amplification into the limelight. Or that so many of these new preamps would use tubes. Or that a $52,000 phono preamplifier would be on the cover of the August 2020 Stereophile.

Sunvalley Audio SV-EQ1616D phono equalizer
I had been studying violinist Joseph Szigeti and happened to be listening to a Columbia 78rpm pressing of the master of the bow playing Brahms’s Concerto in D Minor for Violin and Orchestra, Op.77 (MM 603-8) when I encountered Michael Fremer’s well-composed review of the $52,000 Boulder 2108 phono preamp. I already knew that Boulder made solid, well-sorted products, but even I, the man who once sold $250,000 amplifiers, freaked at the idea of a $52,000 phono stage with (gasp) “house-made” discretely implemented “op-amp” gain stages arrayed on bulk-soldered surface-mount circuit boards.

I forgot all about those op-amp gain stages when I read, “It was like analog on acid. Every note, every musical gesture became the most important, most profound note ever struck—until the next one.” Michael’s wife agreed.

I like listening to “analog on acid” as much as anybody, but must I become a robber baron to experience it?

It seemed fittingly ironic that, when I discovered Mikey’s Boulder story, I was listening to that 78rpm disc through the $150 Grado Prestige 78E mono pickup and the small, $825 Sunvalley Audio phono stage, which is built from a kit.

In addition to its passively realized RIAA equalization, Sunvalley’s SV-EQ1616D’s phono equalizer uses tubes for gain and offers 78rpm enthusiasts a choice of two filters tailored to match either European or American standard play (SP) recording characteristics. It also has selectable EQ for pre-1956 microgroove pressings from Columbia (NAB) or Philips, Capital, etc. (AES), and it has a boost-or-cut high-frequency adjustment.

I remember the first record I played through the SV-EQ1616D because it made me gasp in disbelief.

The $3000 Parasound JC 3+ phono stage had been in the system, and I was using Ortofon’s $755 2M Black moving-magnet cartridge to assess the character of the phono stage in Rogue Audio’s Sphinx V3 integrated amplifier. The 2M Black was sounding unusually vivid, 3D, and exciting with both the Rogue integrated and the JC 3+. The Sunvalley phono equalizer took “unusually vivid” several steps further. The sounds of recordings seemed to burst into my room, charged and luminous.

The Parasound JC 3+ is an exceptionally well-engineered, thinking man’s phono stage. It is good at everything, sonically and measurement-wise, except that it seems a little low on thrill and glow.

I gasped playing the first record because the Sunvalley made music feel more intense and exciting than the Parasound, or any other phono pre I have used in the bunker.

I played “Shhh/Peaceful” from the Mobile Fidelity Sound Lab reissue of Miles Davis’s In a Silent Way (MFSL 1-377) and knew instantly that something unusually exciting was going on. The sounds from Miles’s trumpet cast hypnotic spells as they appeared, lingered, then disappeared. The sense of one intense moment of invention leading to another dominated my attention. I kept taking breaths and holding them.

The SV-EQ1616D was giving me expensive, moving-coil–type pleasures, but I was not using a fancy moving-coil cartridge. The Sunvalley was extracting those pleasures from the $755 Ortofon 2M Black moving-magnet cartridge. Later, when I played “Shhh/Peaceful” with the $7495 Koetsu Rosewood Signature Platinum and a $2700 nickel-core EMIA 1:10 step-up transformer (SUT) feeding the SV-EQ1616D’s moving-magnet input, it would become clear that to experience “analog on acid”—to feel that every note is the most profound note ever struck—it helps to pay the high-end surcharge. You can save a lot of money, though, with a carefully chosen modestly priced preamp like the Sunvalley. Then invest the money saved in the immodest cartridge, and perhaps the immodest step-up transformer, of your choice.

It’s a kit!
I did not have the time to assemble this made-in-Japan kit myself, but I have assembled enough kits to say authoritatively that this one-box phono equalizer is easy and fun to build. If you study the interior photos, you can see exactly what each bit looks like, where exactly it goes, and how it should look when installed. Notice all those hookup wires trimmed in elegant, sweeping curves. All those resistor wires were bent around a pencil or screwdriver shaft to form those perfect smooth bends. Apart from saving money, making bits and wires look artful is what kit-building is about.

Footnote 1: Sunvalley Audio, Sunvalley Co., Ltd., 4-201 Hirokoji Kariya-City, Aichi-Prefecture 448-0844, Japan. USA/Canada Distributor: Victor Kung. Web: vkmusic.ca

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