Here at LKV, we are finding ourselves in a peculiar position. Its looking as if the real competition for our reference level Veros One phono preamp is not some mega buck unit designed and built by a venerable audio manufacturer, but rather our own lower priced Phono 2-SB phono stage. Reviewers, audiophiles, customers and dealers ask us one version or another of this question, “Your Phono 2-SB is so good, can the Veros One really be better?”

The answer is an unequivocal “Yes.” The Veros One takes to a higher level all the things that the 2-SB does so well – resolution of low-level detail, bass extension and definition, clean transients, powerful dynamics, naturally musical midrange and highs, black backgrounds, deep soundstage with solid images, correct textures and timbres, transparent and three-dimensional presentation. If your system has sufficiently high resolution, you will hear the improvement when switching to the Veros One, as did Jim, an LKV customer who owned a Phono 2-SB for about 2 years and then upgraded to the Veros One:

"The new Veros One arrived last week and I've been very impressed with the quality of music that it presents. I've been very pleased with the performance of the 2-SB, and the Veros builds on the qualities of its predecessor. Overall, my experience with the Veros compared to the 2-SB reminds me of long ago when I traded in my 2-way speakers for 3-ways. The high, mid and bass frequencies just sound more balanced, fitting together in a way that is more coherent and natural sounding. Low level musical details also come through more clearly, not in an "in your face" way, but gently, letting me know that the music is more layered or nuanced than what I heard with the 2-SB."[1]

The ultimate test is, of course, to do what Jim did: listen in your own system or in a system with which you are familiar. But there are very specific reasons that the Veros is even better than the 2-SB. I think it will be helpful if I explain what they are.
  1. Measured results.
Listening, subjective though it is, has to be for each of us our own personal, final arbiter. How could it be otherwise? But, measurements properly made and understood can give us a useful, objective basis to guide and test our subjective judgments. For those who might say, “of course Bill thinks the Veros is better, he designed it,” I offer the following measurements that demonstrate a sound technical basis to think that the Veros One is superior to the 2-SB.

The Veros One is significantly better than the Phono 2-SB in three of the four most important characteristics of an audio phono preamplifier: 1) Its distortion is about 40% lower; 2) It has 42% greater dynamic headroom; and 3) It is 25% quieter. In the audiophile world where every little improvement is said to “count,” these are dramatic differences. On the fourth important characteristic, flatness of RIAA response, both of the LKV phono preamplifiers are flat to within +/- 0.1dB (essentially perfect performance).

Distortion. As used with reference to audio electronics, “distortion” refers to bending, i.e., distorting or changing, the shape of the original musical wave form. Music, like other sounds, is carried to our ears primarily by soundwaves in air. When we capture those waves via a microphone and convert them to electrical waves, our goal is to create and transmit electrical waves that are exact copies of the original soundwaves. Unfortunately, all of our amplification devices bend those waves to some extent. This bending is what we call “distortion.” In essence, the distortion becomes part of the reshaped music that we hear.

The greater the amount of distortion, the more the music is changed. The change may be euphonic: for example second harmonic distortion can make the music sound fuller and richer than it did in the concert hall or studio. But, once the music is distorted, one is no longer listening to what the musicians created. To hear all the nuances and emotions in a musical performance one needs a recording and playback chain with very low distortion.

The Phono 2-SB is a very low distortion amplifier, particularly for a phono amp that employs no loop feedback at all. But, the Veros One has even lower distortion, again achieved without loop feedback. Typical measurements of total harmonic distortion (THD) for the Phono 2-SB are 0.008% versus 0.005% for the Veros One.[2] Thus, the Veros One has roughly 42% lower THD than does the 2-SB.

The distortion levels of both designs are, admittedly very low. Some would argue that at such low levels, improvement in distortion levels doesn’t matter. But, it has been our experience in repeated listening tests that the lower we can push the distortion, the better is the reproduction of the low level detail and nuance that give music its meaning and emotion. The vanishingly low level of the Veros One’s distortion is, I think a principal reason for Jim’s hearing the “gently” appearing low level details.

Dynamic Headroom. As the music gets louder, the size of the musical wave measured in voltage increases. Dynamic headroom is a measurement of the amount by which a typical musical signal can increase in loudness before clipping. For discussion let us say that the typical signal at the output of a phono amp is half a volt (0.5V), and that the level at which clipping occurs in that phono amp is an output equal to 5 volts. This phono amp thus has “headroom” to allow a 10 fold increase in loudness of the music: 10 times the typical level of 0.5 volts gives our maximum, pre-clipping level of 5 Volts.

There are two, related reasons that we want to have as much dynamic headroom as possible in a phono amp. First, of course, the music sounds terrible when the waveform clips. So it is very desirable to avoid clipping by having a lot of headroom. Second, as the peaks of the musical wave form get closer to the clipping point, distortion increases. The amount of the increase in distortion depends on how close the signal level gets to the clipping limit. As the signal gets closer to the clipping point, the distortion increases.[3] Thus, we want to keep the signal level far below the clipping limit. The best way to do that is to make that limit very high. In other words, we want to make the dynamic headroom as large as possible.

Contrary to what many audiophiles believe, the chief benefit of having a lot of dynamic headroom (i.e., a high clipping point) is not the avoidance of clipping. That is of course important. But the real benefit of headroom is lower distortion at all signal levels. The higher the clipping point, the farther from that point are signals at all levels and the lower is the distortion imposed on all of them. With lots of headroom, we bend all the musical signals less.

To that end the 2-SB is designed with a great deal of headroom. But the Veros One has even more. In balanced out mode, the Phono 2-SB will amplify a musical signal to a level of 14 volts before clipping (defined as 1% THD) occurs. Taking from the example above the typical phono amp output signal of 0.5 volts, the 2-SB has headroom for a 28 fold increase in signal level (14divided by 0.5 equals 28). That is an excellent headroom figure. But, at a higher price point, we were able to give the Veros One the ability to amplify signals up to 20 volts before clipping occurs, giving it headroom for a 40 times increase in signal size.[4] Thus, it has about 42% greater headroom than does the 2-SB. This translates into not only much less chance of clipping, but also, and more importantly, less distorted, cleaner and more natural sound at virtually all levels.[5]

Noise. Unlike distortion, noise in audio electronic circuits does not involve deforming the musical signal. Rather, noise is added “stuff” – hiss, hum, static, etc. – that has the potential to obscure or drown out the music, particularly the low level detail. Noise is a particular problem in phono preamps because of the tiny signals they must amplify and the huge amplification factors they must apply.

It is very common these days for a moving coil cartridge to have a typical output of only half a millivolt (one-half of one one-thousandth of a volt). Some MC cartridges have even lower outputs, 0.2 or 0.3 millivolts. To render these miniscule signals usable in the rest of the audio system, the phono stage will have to amplify them as much as 1,000 to 10,000 times (60 - 80dB). Any noise present in the signal or created by the phono stage will be amplified by the same amounts. Unless the phono stage is extremely quiet, the low level detail in the musical signal can be buried in the noise and lost.

Importantly, even if you can hear and enjoy the music, the noise may still be obscuring important detail. Indeed, in almost all playback, we are losing some of the music to noise. At LKV our listening experience persuades us that whenever we are able to push the noise floor down, even slightly and even from an already very low level, we hear more of the musical detail and nuance. And that detail conveys much of the emotional impact of the music and makes for more solid, stable images and deeper more revealing sound stages.

For these reasons, we have worked very hard to reduce the noise of the 2-SB and the Veros One to extremely low levels. Indeed, the Phono 2-SB has earned a reputation for being a very quiet design. With a moving coil signal to noise ratio of 66dB it is one of the quietest phono amps available today.[6] The Veros One is even quieter, having an MC signal to noise ratio of 70dB. Both of these ratios are measured over the unweighted audio band, with the inputs shorted, and referenced to an input of 0.5 mV. The ratio for the 2-SB is calculated at a gain of 59dB. That for the Veros One, 70dB gain. Stated this way in decibels, the noise levels of the two LKV phono stages seem very similar (66dB versus 70 dB). However, the logarithmic basis of decibels is, in this instance misleading. When one works the math, it turns out that the noise voltage of the Veros One is approximately 25% lower than that of the 2*-SB, a quite significant reduction that in our listening tests lets us hear further into the musical details and subtleties.

[Here ends part 1 of this article. I part 2, to be posted in a week or so, we will pick up with physical and operational differences between the two designs.]

  1. [1] Jim, who lives in the Southeast United States, gave us permission to use his comments for promotional purposes. He asked to be identified only by his first name.
    [2] These measurements are typical results based on the testing we do of every unit before it is shipped to a customer or anyone else. For both the 2-SB and the Veros One, these measurements are made in single ended mode, 59dB gain, at 1V output. Distortion measurements under other conditions and frequencies show similar differences, as do measurements of transient intermodulation distortion.
    [3] Designs using loop feedback behave somewhat differently as clipping is approached than do those that use no such feedback. Feedback designs are more susceptible to harsh clipping whereas non-feedback designs are more prone to gradual compression of musical peaks and therefor to distortion as the clipping point is approached. One has to pick one’s poison, so to speak. The many tradeoffs in using loop feedback and my reasons for avoiding it are discussed in my article “ Why I Choose to Design with Discrete Components, Not Op Amps,”
    [4] The headroom figures given in the text are maintained across the audio spectrum from 20Hz to 20kHz. For those who care, the voltages given in the text are all RMS.
    [5] Expressed in decibels, the calculations in the text translate into headroom of 32dB for the Veros One and about 29dB for the 2-SB. I use the gain factor calculations in the text because they better illustrate the % difference in headroom between the two units. The decibel calculation tends to obscure the difference unless one is conversant with the way their logarithmic nature handles such differences. The careful reader will note that these headroom numbers are a little different than those in our specs for these designs. That difference occurs because for simplicity I have used slightly different assumptions in this article.
    [6] A comparison of the signal to noise ratios of the 2-SB and Veros One to those of other very well respected phono stages is available on the LKV Blog. “Updated Comparison of S/N Ratio in 7 High End Phono Preamplifiers,”