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From Ultimate Audio March/April 1998
Subscriptions: $18.95/year US, $39.95/year overseas
www.ultimateaudio.com


Birth of a New High-End Tube Company

Herron Audio VTSP-1 Tube Preamplifier/
VTPH-1MC Phono Preamplifier

BY RICHARD S. FOSTER


I don't think anyone, in their wildest imaginations, envisioned the impact that the Internet would have on high-end audio! As a result of the Internet, countless manufacturers, record labels and print and online magazines have websites, providing instant access to information on current, new and impending products. And audiophiles can surf the web to discover new companies and products. It was through a vinyl Internet mailing list that I came across the VTSP-1 Tube Preamplifier/VTPH-1 Phono Preamplifier combination from Herron Audio.


A LONG GESTATION TIME

While Keith Herron is a relatively new name in high-end audio circles, he's been perfecting his craft for many years. In the course of our discussions, I found out that he began building equipment for a close group of friends - who later coaxed him into becoming a high-end audio manufacturer. Herron was very careful not to sound egotistical when saying that, "I became a manufacturer because I felt I could design a better product than what was out there." And he certainly has the credentials to mount an attack upon the state-of-the-art! Herron's last position was in pro audio circles as Director of R&D from 1989 to 1992 for Ampeg, Crate and Audio Centron.

HERRON AUDIO'S DEBUT

Herron's first effort was the VTPH-1 phono preamplifier. While the bulk of this review deals with the Herron Audio phono/preamplifier combo, I did have an opportunity to spend some time listening to the phono section on its own before the Herron VTSP-1 preamplifier arrived.

The Herron phono stage gives a very different perspective to a recording. Sonic Frontiers's Phono 1 produces a midhall perspective. Enter the Herron phono stage: You're seated much closer to the orchestra, somewhere around Row 5. From this position, the Herron allows you to hear right into the stage, with even greater detail present, than the Sonic Frontiers.

The Herron Audio phono preamplifier produced something I've never heard from an audio system before: live, I mean LIVE, in-your-room clarity. The clarity and the absolute transparency this phono section delivers takes the listener not into the world of reproduction, but production. Great recordings assume their full, explosive, lifelike dynamics, with bass that is tight, deep and articulate complete with shading and definition; lightning-fast transients; exceptional control of the leading and trailing edge of the musical wave form. Tonally and harmonically, the Herron transports you to a place you've never been before.

Finally, the phono section interfaces with and brings out the best in a moving-coil cartridge. Take, for instance, the Lyra Parnassus D.C.t cartridge - whose extremely low (0.2 mV) output proves a true workout for any phono stage. I never heard the true voice of this masterpiece from Japan until the Herrons arrived. (There was never any noise problem when this cartridge was mated to the Sonic Line 3/Phono 1 combination, either.) The Herron allowed the Parnassus D.C.t's ability to delineate individual orchestral layers within the soundstage to be fully appreciated. Played through the Herron, the Parnassus D.C.t is truly one of the world's greatest cartridges.

The Herron combination allows the
dynamics
to explode in your listening room

THE PREAMPLIFIER ARRIVES

Listening to the Herron phono stage/line stage combination (linked by the sonically neutral Nordost SPM reference interconnects) took my listening experience one step closer to the illusion of live. The first album I threw at the Herron combination was Saint-Saëns's Symphony Number 3 in C minor, Op. 78. While the Paray Mercury, the Fremaux EMI or the Munch RCA are the versions of choice for many, my particular favorite is Ansermet conducting his Suisse Romande (Decca SXL 6027). Lovely, velvety deep bass notes float ever-so-lightly over the orchestra. There's an authority from the king of all instruments in the deep bass regions - not only the kind you hear, but the kind you feel. Add to that sumptuous strings and a horn section to die for. Ansermet's 35-year-old masterpiece unfolds before you in your listening room.

Another orchestral masterpiece that really tests the mettle of any system is Zubin Mehta and the Los Angeles Philharmonic performing Edgar Varese's Arcana (Decca SXL 6550). A cacophony of sounds awaits the listener. Arcana is scored for a large string section, an augmented wind section and 39 percussion instruments. The Herron combination, allows the dynamics of the timpani to explode in your listening room.

For sheer aural insanity, there's Ionisation with DesRoches and the New Jersey Percussion Ensemble (Nonesuch 71291). Ionisation is one of the most dynamic recordings ever put on LP. Scored for percussion and sirens, the Herron combo elevates this recording to a new level of realism, with a degree of clarity, dynamic impact and openness that is truly breathtaking.

Then I turned to an all-time-favorite recording, The Missouri Breaks by John Williams (United Artists UA 623-G with pressing ring), complete with its crackling transients. The title cut has always been a workout for any system. The Herron phono playback system clearly stands the test by defining the attack of each guitar, bass, horn, drum and percussive instrument on this cut, while the razor edge (without brightness) of the harmonica hauntingly sings through your system.

One of my favorite opera reference recordings is Verdi's Rigoletto (Decca SET 542/4) with Richard Bonynge leading the helm of the mighty London Symphony Orchestra, Ambrosian Singers and the voices of Milnes, Sutherland, Pavarotti, Talvela, Te Kanawa and Tourangeau. This phono playback system brings the wonderful theater and action of this tragedy into your home. With all its goings-on, Side 6 brings out the weaknesses in any system: all the main stars as well as an orchestral storm, vocals from the left rear hall (which sound sooooo far away) and the gong of the clock at the stroke of midnight. This is a very complex piece of music, which the Herron unravels with absolutely no congestion present; other systems may shut down and not maintain an open, airy acoustic.

As I was finishing the review, Herron sent a new phono section. This one didn't have any resistors in the signal path to pad the gain, and the capacitance in the right channel was reduced by 12 picofarads. It seems Herron found that it was important to match the effective capacitance of a circuit board trace for both channels - and the results were startlingly improved. When board channel capacitance matches exactly, the music shows greater focus and clarity and more contrast in the dynamic range.

DELIVERING THE GOODS

With the Herrons in place, all is as it should be with any recording. It's hard to put a finger on the sound of these units. They seem to be just a delivery system and have no sound of their own. Just clear, clean, dynamic and unfiltered music delivered to your speaker system. Every recording has a different sound as well as acoustic. Whatever is placed before the Herrons is heard with no additional distortion or coloration.

If you want the best (that I've heard) in line stage and phono reproduction, from the deepest, tightest, cleanest bass your system can reproduce to the silkiest, most open highs you can hear, listen to what's happening at Herron Audio. You'll be glad you did.


Herron Audio VTSP-1 Preamplifier and VTPH-1 Phono Preamplifier, Herron Audio, 12685 Dorsett Rd., Suite 138, St. Louis, MO 63043. Tel.: (314) 434-5416. Website: www.herronaudio.com. Designer: Keith Herron. Price: Phono preamplifier: $2,750 (MM), $3,250 (MC); Preamplifier: $3,650.


TECHNICAL HIGHLIGHTS

VTPH-1MC PHONO PREAMPLIFIER

Herron Audio manufactures two versions of their phono preamplifier. For owners of moving-magnet cartridges, there's the VTPH-1MM with 44 dB of gain. Alternatively, there's the VTPH-1MC with 66 dB of gain for moving-coil users.

After much experimentation, Keith Herron concluded that the only way to achieve the noise levels required for the amplification of low-output moving-coil cartridges was using a single FET (field effect transistor) per channel. According to Herron, he "spent a considerable amount of time finding the right device and designing the right power supply to go with it." In the end, the FET provides for an additional 22 dB of gain.

The phono section is best described as a Class A, with two triode sections per gain stage in a unique distortion canceling configuration and passive RIAA equalization circuit configuration. No global feedback is used in either the phono section or preamplifier. Four Sovtek sourced 12AX7s and one 12AT7 dual triode tubes are used in the VTPH-1. The phono section with three gain stages is absolute-phase inverting; the moving magnet with two gain stages is noninverting.

One other problem that I ran into (but most others probably won't) was an issue of the Herron's compatibility with my Sonic Frontiers Line 3 line stage. The Line 3's overload margin (4 V RMS) wasn't enough for the Herron phono preamplifier when used with the Clearaudio Insider Gold, necessitating Herron to reduce the unit's gain from 66 to 62 dB. This modification isn't needed when the Herron phono section is used with Herron's own preamplifier - or most other units (though ARC Reference preamplifier owners should be aware of input limitations).

Herron eschews the use of switches in the VTPH-1MC since he feels "switches do not work very well for very long at the tiny voltages and currents that come from a moving-coil cartridge." The only adornment on the front of the unit are three LEDs (representing power, filament - which gradually brightens as the voltage slowly increases - and output) arranged in a vertical array on the right side of the unit.

The phono section's default loading value is 47 K. Herron strongly believes in maintaining signal purity, so changing loading values requires soldering appropriate resistor values into the unit. The owner's manual contains instructions on changing the unit's resistive loading values.

VTSP-1 PREAMPLIFIER

The VTSP-1 all-tube stereo preamplifier contains four matched Sovtek 6922 dual triode tubes. Overall gain of the VTSP-1 is 14 dB - so when paired with the VTPH-1 preamplifier, there's a total 80 dB of gain. This, in combination with the unit's extremely low noise floor, is more than enough to interface with even the lowest-output MC cartridges.

There are many innovative twists to the preamplifier's design. For example, there's the design of the power supply in both units. Herron's objective when designing the power supplies was "to provide a clean, rigid voltage source to the tubes and isolate them from outside power line perturbations in both the phono and preamplifier sections." Both units have four levels of high voltage regulation; the preamplifier and phono section have 78,000 and 72,000 µF of storage capacity, respectively. To reduce circuit noise to vanishingly low levels, Herron uses a star grounding arrangement where every signal ground has an independent path to a central ground point.

Finally, Herron "aligned" the power supply and the gain stages so to "tune out" resonances that lead to nonlinear frequency response, timing errors and soundstaging anomalies. When designing, Herron found that static tests don't always reveal the unit's performance, so he developed his own tests to correlate sound with performance.

Three knobs facilitate input selection, balance and volume, three toggle switches control tape/source, mono/stereo and the mute/listen and three LEDs indicate power, filaments and output are located on the front of the preamplifier. The output LED turns red when the unit is muted and loses its green brilliance when switched to mono.

Volume levels are controlled using Herron's 128-step, perfect-tracking volume control. To quote the manual, "This innovative 128-stepped servo control provides extremely accurate tracking for each channel across the full volume ranges, while retaining the convenience of a conventional volume knob." The one negative was that the 128-stepped attenuator tapered off too rapidly at the low end when using the Clearaudio Insider Gold cartridge. This problem is easily addressed by changing a part in the volume control servo; consult the factory.

Finally, Herron suggested using low-capacitance cables to avoid any high-frequency roll-off. The general rule of thumb is that the input impedance should be at least 10 times the output impedance of the previous stage. So the 500 ohms output impedance of the phono section should "see" at least 5 Kohms - though Herron thinks the value should be really 100 times, or 50 Kohms. In the case of the Herron units, the phono section "sees" a load of 100 Kohms. After some investigation, Nordost kindly lent me their SPM Reference, low-capacitance interconnect cables for this review. (To be fair, the Nordost was first inserted into my reference system before reviewing the Herron equipment.)


Copyright © 1996 - 2017 Herron Audio. All rights reserved.
Herron Audio, div. of Herron Engineering, Inc.
12685 Dorsett Road #138, Maryland Heights, MO 63043 U.S.A.
phone: 314-434-5416