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Positive Feedback ISSUE
as reviewed by Karl Lozier
The VTSP-2 in silver<
Is this the preamplifier that breaks the unspoken price/performance barrier presented by that elite and highly-promoted group of preamplifiers selling in the $10,000 to $20,000 range? That group actually breaks down into three subgroups centered around ten, fifteen, and twenty thousand dollars. The space between each of these price points, as well as the one between five and ten thousand dollars, is sparsely populated. The explanation for this centers around marketing decisions. The top group will be populated, to some extent, by over-engineered, visually impressive styling exercises. Sonically, they tend to emphasize (or possibly overemphasize) some aspect of their performance so that they stand out from other preamplifiers in a showroom demonstration. These preamplifiers often sound pleasing, but are inaccurate, even distorted. Also, some of these ultra-expensive preamplifiers only sound their best when paired with their company's amplifiers.
Keith Herron's approach has been carefully implemented during the past few years. It started with the surprising, though low-key, acceptance of his first preamplifier design, the VTSP-1. The fact that his background was strictly on the professional side of audio has great significance. Professional audio places great emphasis on reliability and dependability. The well-known "KISS principle" (Keep It Simple Stupid) frequently applies to professional products. This is not a negative, since "simple" often translates to "better sounding." The VTSP-1 quietly garnered acceptance from music lovers and audiophiles, something that is really tough to do with a new product from a new company. Everything about it, including its design and promotion, was simple and low key. The price was moderate, and the sound quality was surprisingly good. I and others have described it as neutral—so neutral that it was hard to tell if it was a solid state or vacuum tube design. It seemed to have none of the negative qualities of either.
As a newcomer to consumer audio, Herron realized that pricing was important. Careful design allowed all of his early products to share the same chassis and slightly generic appearance. No attempt was made to incorporate brand-name parts. All parts were chosen on the basis of listening tests after passing measurement tests. Features were eliminated based on two criteria, one being extra expense and the other that inclusion would mean an unacceptable degradation of the sound. After my very favorable review of the VTSP-1 (for another magazine), I started bugging Keith about features that I would like to see in later models. The features I requested included repeatable volume settings, a phase reversal switch, and new esthetics, in some color other than black, plus, for others, a small remote control. (I almost never use a remote control in my main system, as this lets me maintain my membership in the Society Against Advancement of Couch Potatoes.)
Two years ago, at CES, I was nearly abducted and dragged into Herron Audio's demonstration room. "Look," Keith commanded, "everything you asked for and more. How do you like it?" I liked it instantly! Though it had compact dimensions similar to those of the VTSP-1, it had a very attractive front panel finished in subtly brushed aluminum. It was bilaterally symmetrical, logically laid out, classy, and understated. It was notable for—but not dominated by—its central, illuminated readout area. Its operation was simple and logical, yet sophisticated and impressive. When I turned on the power switch on the back panel, all of the small front-panel LEDs blinked. Then the oval central area counted down visually (from 60 to 0 seconds) and a small muting indicator light went on. When the countdown reached zero, the central readout changed function and showed the gain setting in a scale from zero to 100. Then the mute indicator blinked off : everything was ready to go. Simple and classy, but very sophisticated. The 180-degree change from the initial simplicity of Herron's designs in no way changed his goal of producing the best, most natural sound.
The case now has an attractive black finish and design, with the face plate being available in black or silver. A small shiny knob to the right of the oval controls volume, and the matching knob on the left is the balance control. A row of five small blue LEDs to the left of the oval are the indicators for the corresponding lower row of input buttons. The row of five different-colored lights to the right of the oval correspond to the lower row of function buttons, including mute, mono, invert (phase), tape, and display (brightness). I like the blue LEDs on the left bank of indicator lights, but not the different colors of the right bank of lights, though they are off most of the time.
The VTSP-2 has two more tubes than the VTSP-1, necessitated by the new phase-reversal circuitry. The tubes are selected Sovtek 6922s. Tube swapping is not encouraged. The sound would change if you substituted NOS or other tubes, plus Herron's selected Sovteks are as dependable as tubes come. Replacements are easily obtainable from Herron, who can exactly match the tubes that came with that particular preamp. Though each increment of the superb sounding volume control that Herron uses in the VTSP-2 does not offer the same amount of gain, each is approximately half a decibel. The manufacturer refuses to change the control so that it would be more consistent, and it is the best sounding control that Herron has heard. Part of the outstanding sound offered by this new preamplifier is due at least indirectly from the circuit changes made to allow for its greater flexibility. Evidently, some of the work done to add features resulted in improved audio quality as an unexpected bonus.
It is now time (perhaps past time) for me to share my feelings about the VTSP-2. Its sound, like its appearance, is low key and straightforward. It does what it was designed to do simply and easily, with no fuss. The VTSP-2 amplifies signals with no audible alteration or degradation. I did not follow my usual burn-in procedures with the VTSP-2. Keith Herron asked me to see how I thought it burned in, and how quickly. Most of the audible changes occurred during the first hour, followed by about twenty to twenty-five hours of subtly improving quality. In another departure from routine, I wound up simply listening to music instead of comparing or evaluating. Though of course I eventually got around to doing my job, a couple of early impressions stayed with me. While the VTSP-1 always struck me as neutral, the VTSP-2 has some subtle but definite classic tube characteristics, including a bit of fullness in the upper bass to lower midrange and a bit of added sparkle in the upper midrange to lower treble region. I do not have any way to prove those impressions, but the added touches are musical, not analytical.
As with most audio components, particularly preamplifiers and CD players, using Bright Star Audio's Reference Isolation platform added a noticeable amount of clarity, plus greater extension in the bottom end. Placing Bright Star's small damping platform on the top of the chassis may have helped in a subtle way in very loud passages. As I always do with front-end components, I used a PS Audio Power Plant to supply clean, regenerated clean AC, with the usual 60Hz setting. I used Kimber's top power cord, the Palladian PK-10, and their Select loudspeaker cables. Keith Herron says that the very modestly priced DiMarzio loudspeaker cables are a fine match with his amps and preamplifiers. I have received samples of the attractive DiMarzio cables, and should be reviewing them before long. Their power cord is definitely an overachiever, but I have not yet hooked up their loudspeaker cables.
With his strong feelings about timing, pace, and rhythm, Herron developed unassuming-looking but high-performance interconnect cables to use with his new preamp. I believe that the interconnects have to be ordered at the time the preamp is ordered. The Herron cables do not add any fullness or richness that would destroy musical timing. Though their tonal balance is subtly different than that of my long-time reference interconnects—the all-silver Kimber Select KS 1030s—Herron's interconnects were outstanding, particularly considering their relatively reasonable price, which is one-tenth that of the Kimbers. In addition to other subtle differences, the Kimbers added a noticeable degree to the deepest bass, below 40Hz. This was readily apparent in many of the selections on Epics.
I started to pull out recordings that I thought would be hard to reproduce without adding distortion or harshness, but I soon gave up. I was unable to find any faults with the VTSP-2. Is it possible to be more positive than that? None of the newly remastered RCA or Mercury SACDs caused any trouble. For musical beauty, try Ravel's Daphnis et Chloe, or Telarc's new Epics, a particularly fine, well conducted compilation with outstandingly sound. Do you have space for a quartet of world-class vocalists (plus a few instrumentalists) in your listening room? If so, prepare to be absolutely thrilled with The Manhattan Transfer's Vibrate album, which features superb harmonizing, fine solo singing, and great pop and jazz selections. Turn up the volume a bit on the VTSP-2 and be completely immersed. Home listening just doesn't get much better.
I started this review by asking whether the Herron VTSP-2 is "the one." I must conclude that it is the one preamplifier that competes head on with those at two, three, and four times its price. I would be pleased to receive review samples attempting to be proved wrong. Until then, I shall be listening in bliss to the VTSP-2. Karl Lozier
Thanks Karl for the nice review. As you know this is
the first review on the VTSP-2 that is published in the U.S.. I just got word
that the VTSP-2 received "Product of the Year 2004" in HiFi Review Magazine
in China. Two other magazines in China gave it top ratings, one saying that it
has no competition. This gives support to you with your review.
The VTSP-2 in black
A few words with Keith Herron...
Keith Herron, the owner and principal designer of Herron Audio, graduated from Iowa State University with a bachelor's degree in Electrical Engineering and is a Registered Professional Electrical Engineer. He was formerly director of R&D for Ampeg, Crate, and Audio Centron, and he combines a strong background in electronics, math, physics, and music with a keen ear and open-minded analysis of audio equipment design. He describes himself as an audiophile, a lover of music, and a "former" musician.
What is your design philosophy?
The design process has often involved rigorous application of physics and mathematics and investigation of the smallest details in circuit analysis. It has involved a new definition of what is audible and listening evaluation with a discerning ear—not listening for highs or lows, but for focus in time. If the beginnings and endings of events are clear and easy to decipher, then the highs and lows must be correct. Timing is one of the most noticeable aspects of natural sound. As a musician, the feel of the instrument is conveyed through the timing of the sound as an instrument is played. As an audio circuit designer, I can immediately hear if the timing is right or not right, without even facing the speakers. As we say, "Immediately you know."
You have said that remote controls have a negative impact on the sound, but you are now producing preamplifiers with remote control. What has changed your mind about this?
It is true that decoding a signal from a remote control device usually requires a clock signal that measures the length and timing of the encoded pulses from the remote, and clock pulses contaminate the audio signal. Utilizing the fact that our remote control signal is modulated by a 38kHz infrared carrier, we are able to turn on the decoding process when a 38kHz signal is detected through an analog filter, then turn off the decoding process when the signal from the remote stops. A red LED in the oval display window indicates the operation of the decoding circuitry. Other functions in the VTSP-2, such as displays and relays, are operated by pure DC from individual latches, and are not pulsed or modulated as is commonly done. This also prevents contamination from entering the audio path.
What made you decide to add the (invert) absolute polarity function to the VTSP-2?
Many recordings are made with equipment in the chain that inverts the absolute phase of the audio signal. In phase-coherent playback systems, the absolute polarity of the audio signal can make a night-and-day difference in the quality of the playback. The VTSP-2 is designed to provide both correct and inverted phase without altering the character of the sound in any other way. This was not a simple task.
Many audiophiles are reluctant to use tube components because they are concerned about tube life and the availability of replacement tubes. What are your thoughts about this?
Tube life can be a concern. Many designs, even preamplifiers, have the disadvantage of short tube life. I have found through extensive Investigation that by using the right tube for the right circuit application, and by operating the tubes at low current and voltage (low power and resultant heating), tube life can be extended while at the same time obtaining maximum audio performance. Many of the nonlinear characteristics (distortions) of certain tubes can be canceled out with appropriate circuitry. This fine tuning applies to specific tubes, which is why I do not recommend "tube rolling." Some tubes will become noisy due to contamination during the manufacturing process of the tube, but most will last for many years.
On your website, I have seen a preamplifier called the HL-1 that looks like the VTSP-2. What can you tell me about it?
The HL-1 is a solid state preamplifier that has the look and many of the features of the VTSP-2. The HL-1 has an optional internal solid state phono stage. Unfortunately, there is no space available in the VTSP-2 for any type of phono stage.