Vendetta Research SCP-2a - $3.000 phono preamplifier
Few people in the audio business would deny that John Curl is an audio design genius—arguably the greatest one of our generation. He designed and built the electronics for Mobile Fidelity's SuperMaster and David Wilson's (of Wilson Audio) UltraMaster tape recorders, two of the three best analog recorders in the world. (The other is Keith Johnson's home-brew unit.) He designed the JC-1 head amp and JC-2 preamplifier sold under the Mark Levinson name some years ago. He designed head amps for SOTA, Michaelson & Austin (TVA), and has done consulting work for more high-end companies than you can shake a stick at.
Yet, for all his acknowledged design brilliance, fame has not brought John Curl fortune—like so many geniuses, he has earned a reputation for being hard to deal with. It's not that he drives a hard business bargain; quite the opposite, in fact. He has been cheated, defrauded, and ripped off by some of the best-known names in audio. His "problem," as seen by his clients, is that he an idealist of the first order, with strongly held ideas of how things should be done: ie, as well as possible and hang the cost. In the pursuit of audio perfection, Curl little comprehends the meaning of "compromise." His designs tend to be truly no-holds-barred, using the best components money can buy to produce the best sound and highest reliability the state of the art allows.
This approach is all well and good when cost is, in fact, no object—when the goal is to design the best tape recorder in the world—but it is not a formula for success in a competitive consumer market where price is as important as quality, if not more so. Consequently, almost every design he has developed for clients has been modified to make it "more affordable" or, in some cases, to make it just different enough that it could be used without reimbursing him for his efforts.
Finally, in 1981, fed up with the restrictions that consulting work placed on his designs, Curl founded Vendetta Research to produce his own products. (The inspiration for the name? "I'll show the bastards!") Vendetta's best-known product was the TCP-1 phase-coherent electronic crossover, but the firm never really took off because it was never promoted. Most audiophiles, including those who've heard of John Curl, don't even know Vendetta Research exists. Now that you've read this, you have no such excuse (footnote 1).
Vendetta's newest product, the SCP-2 preamplifier, is typical of the JC design approach. To begin with, while it is a preamplifier, it is not a control preamplifier. The SCP-2 accepts the output from a MC cartridge and delivers an RIAA-equalized output at line level; ie, suitable for feeding a power amplifier. Second, it inverts polarity, at a time in audio history when this is not considered a good thing. (The instructions call attention to this and suggest that it be "taken into account when making comparisons," as though this was always possible.) Third, at $1895, it is the most expensive stand-alone solid-state phono-preamplifier on the market. And fourth, it is not just a dual-mono unit, it is actually two completely separate—physically as well as electrically—mono units. (Curl explains that that's what Japanese consumers wanted, and he targeted them first because they are less price-conscious than Americans.) The two channels are, however, available on request in a special frame that ties the two units together side by side in a rack-mount adaptor.
Normally, each channel of an SCP-2 comes in two pieces: the preamp itself, attractively finished with walnut end panels, and a separate power supply, the SCP-1. This contains an Avel-Lindberg 30VA toroidal transformer and delivers regulated plus and minus DC rails to the SCP-2 via a 6' umbilical cord.
Construction is to a very high standard, the circuitry for each channel being carried on two gold-plated, double-sided printed circuit boards. Close-tolerance resistors and Rel-Cap polypropylene-dielectric capacitors are used throughout, and socketry is by Tiffany. Cartridge loading is adjustable from 10 to 200 ohms by means of an internal potentiometer, which means the adjustment can be done while listening—an unusual feature offering a distinct advantage over the typical plug-in resistor arrangement. On the other hand, if you prefer just to set the loading to the cartridge manufacturer's recommendation, you can do that, too, but you'll need an ohmmeter; there are no resistance calibrations on the pot. Either way, the only potential hitch is that the loading pot is accessible only by removing the SCP-2's top panel, which requires the use of a smaller Phillips-head screwdriver than many hobbyists are likely to own.
The SCP-2's symmetrical cascode input stage uses DC-coupled complementary FETs that act as a single stage. The HF part of the RIAA playback equalization is passive, and there is no feedback around the first stage, but some can be added if desired to reduce the input impedance to below 10 ohms minimum. The second stage consists of complementary symmetrical FETs, around which negative feedback is used for the LF portion of the RIAA EQ. Each stage has its own FET power-supply buffer for minimum noise and intrastage interaction. A high-quality op-amp is used to provide a DC-servo for each stage.
The specs of the SCP-2 are impressive enough: 0.1Hz-1MHz bandwidth, 90dB of S/N ratio, 0.01% harmonic and IM distortion at 3V out. But, as usual, specs don't tell the whole story—this component's performance is astonishing!
Equipment used for my tests included the Ortofon MC-3000 cartridge in the Well-Tempered Arm, the SOTA Star Sapphire turntable (footnote 2), the Threshold FET-10HI line controller and SA-1 power amplifiers, and Sound Lab A-3 speaker system. Audio interconnects were Monster M1000, speaker cables were MIT Music Hoses, and the listening room is extensively treated with ASC Tube Traps. Program material consisted of discs from Sheffield, Opus 3, Telarc, London, and Reference Recordings.
The MC-3000 cartridge has the second-lowest output of any MC I know of: 0.1mV at 1kHz. (Only the MC-2000 is lower, at an appalling 0.05mV.) It requires a prodigious amount of gain, and an extremely low-noise step-up, and the fact is that, to date, I have not found any head amp that met the MC-3000's needs in both areas at once. Every one I tried that had adequate gain had entirely too much hum or hiss or both, so I have been forced to use the T-3000 step-up transformer Ortofon makes for that cartridge. The sound has always been excellent, but I have had no way of knowing how much the transformer may have been affecting the sound, or in what ways. For this reason, it was impossible for me to directly compare the SCP-2 with my previous reference preamp, the FET-10PC, because the latter could not be used without the step-up transformer. It must be understood, then, that the comparisons which follow are between the SCP-2 by itself and the FET-10PC with the Ortofon T-3000 transformer.
First, it must be said that the differences between the SCP-2 and the FET-10PC/T-3000 were not dramatic. They were, in fact, subtle, but the SCP-2 was clearly superior in every respect. I won't enumerate the sonic areas; you know them all now. Suffice to say that, with the Curl phono preamp, every disc I played sounded a little more like a master tape than it did through the (nonetheless superb) FET-10PC. I found this rather disconcerting, though, because I really believed the FET-10 preamp was close enough to perfection that there was little room for improvement. After all, the FET-10 had passed my bypass tests with flying colors. How, then, could the SCP-2 be that much better? Obviously, because bypass tests are not necessarily any more reliable than A/B tests.
I am beginning to understand that the major reason "controlled" A/B tests usually fail to reveal small differences is because of lack of system familiarity: most, if not all, of the participants are hearing an unfamiliar system. This may also explain why bypass tests often fail to reveal small differences which, after prolonged listening to a new component, are suddenly audible from the same bypass tests. Case in point: Initially, I could not hear either section of the FET-10 when it was inserted into the system. Now I can. I can also hear quite noticeable differences between it and the SCP-2. But I am unable to tell, now, with the SCP-2 in circuit, apparently because I haven't used it long enough to zero-in on what, if anything, it is doing to the sound that it shouldn't be doing. To date, it seems to be doing only what it should, and superbly at that.
The SCP-2s I tested were the standard version, with 62dB of gain. This was barely enough for the MC-3000, but it was enough with the system gain cranked full up. What flabbergasted me was that, at listening levels peaking at around 95dB, there was no audible noise from the SCP-2 at all (footnote 3). When no disc was playing, there was a very faint, muted hiss and not a trace of hum. Playing a disc, the hiss was completely submerged under the surface noise. As far as noise is concerned, the MC-3000 is almost a worst-possible case, and the SCP-2 was able to handle it with aplomb. This has got to be one of the quietest preamplifiers around. I would advise, however, that you order the high-gain version for an MC-3000; it will be absolutely necessary with the lower-output MC-2000.
The Vendetta Research SCP-2 is the costliest phono preamplifier on the market; it is almost certainly the best, and is well worth the money if you can afford it. I hope it brings a measure of fortune to John Curl; he deserves it.
