R.E. Designs SCPA 1 Six-Channel Preamplifier
The SCPA 1 is a very simple, very focused product that will not appeal to a large cross-section of home-theater consumers. For home-theater perfectionists and multichannel audio pros, however, this product offers something extraordinary. Although simple, it is noteworthy for several reasons and its sound quality compared to that of more expensive preamps might surprise you.
R.E. Designs is the labor of love for Dan Banquer, who designs and builds preamplifiers and amplifiers in a Boston suburb. Dan foregoes fancy features and appearance in favor of a strongly directed design goal -- ultra-low distortion, ultra-low noise, and ultra-high fidelity to the input audio signal.
What it is
The SCPA 1 is a six-channel preamplifier -- six inputs, six outputs -- thats it. There is no input switching. The front panel has six high-precision multi-turn pots, which allow for independent level control of each channel separately. Each multi-turn pot can be locked in to position once you have set them where you want them. There is also a master volume control, a massive six-gang 24-position stepped attenuator. This device needs a very large knob to provide the leverage needed to overcome the contact force of the six attenuators on that single shaft. All channels of the stepped attenuator are precision matched during assembly to within 0.1dB across the operating range. Most consumer surround processors allow adjustments of 1dB, which leaves room for audible channel-to-channel imbalance. The SCPA 1 can be used in conjunction with consumer surround-sound processors to achieve perfect channel balance, rather than having to live with 1dB compromises. In the pro-audio world, the SCPA 1 offers absolute precision channel balance for mixing and mastering of multichannel soundtracks.
The rear panel contains six RCA inputs and six RCA outputs. The power cord connects to an IEC socket, and thats it for the back panel. As you can see, the SCPA 1 is a very directed, very focused product that, as previously mentioned, will not appeal to a wide consumer audience. Nevertheless, it is a component that I will personally miss greatly when it comes time for me to return it the manufacturer.
What it does -- two-channel music
The SCPA 1 is a remarkable sounding audio preamplifier. It is incredibly neutral, equal to or better than any preamp Ive heard at any price, in any system. The noise levels at the outputs are exceptionally low. Its bass capabilities are flabbergasting! Bass extension seems unlimited, which illustrates how full-range subwoofers sometimes uncover subsonic errors that were obviously missed during production. In the bass-frequency range, the SCPA 1s detail and differentiation of nearby frequencies sets a new landmark in my listening experience. Ive simply never heard so many discrete bass frequencies produced simultaneously before. The midrange is utterly impossible to criticize unless you prefer colorations, added distortion, and lower resolution. Differentiation of nearby frequencies, through the midrange, is spectacular. Pedal and lap steel guitars produce tones that can be only a few hertz apart. Most preamps, including the expensive ones you know about, homogenize several nearby frequencies into a single sound. The Audible Illusions M3A is widely recognized as one of the 10 best preamps in the world, yet even it, with only a few days on fresh tubes, cannot approach the fine differentiation of nearby frequencies that the SCPA 1 achieves with ease. The pedal and lap steel guitars sound far more realistic on the SCPA 1 because of its capability to produce the separate overtones as separate sounds, rather than squeezing them into a single sound. I believed that the detail in the bass and the differentiation of nearby frequencies was not being captured in commercial recordings. I knew it existed in live performances, but I have never heard it reproduced in a home-audio system before. To hear this level of accuracy, and not from a component costing five figures but from one with six channels costing $2700, causes you to screw your head like a confused puppy. The use of the word "accuracy" in reviews of all audio components, even my reviews up to this point, should be subject to eradication simply because those components were only accurate compared with themselves. R.E. Designs SCPA 1 raises the accuracy bar.
By now you are no doubt wondering how this extraordinary feat was achieved. Well, shut my mouth Dan did it with OpAmps. No kidding, new Burr-Brown OpAmps. What I mean is that he had to get the other elements right too -- circuit board layout, component selection, power supply design -- all the usual suspects. But the 18dB of gain comes from an OpAmp-based circuit. Ive personally witnessed OpAmps improve from their drecky sound all the way through the 1980s, followed by the several leaps and bounds in improved sound quality in the 1990s, which were mostly the result of a constant battle for supremacy between Burr-Brown and Analog Devices. However, even with the improvements Ive heard for myself, Ive never heard anything quite like the sound of the SCPA 1 from an OpAmp-based product before.
You think tube preamps are the ultimate for music? (Incidentally, Ive used tube preamps exclusively for over ten years now.) Delusion city! In comparison to the SCPA 1, tube preamps have awful bass extension, poor bass-pitch definition, an inability to differentiate multiple nearby frequencies, an excessively high noise floor, a lack of transparency, a lack of dynamic precision, overly shimmery highs, and distortion-enhanced string tone. They also exhibit homogenized depth compared to what is actually present on the recording (it may be great even phenomenal depth but it doesnt accurately represent what is on the recording), and a general shortage of resolution. This applies to the best tube preamps in the world. Preamps no reviewer in his right mind would criticize so openly and brutally unless hed heard the same music on the same system with those preamps and the SCPA 1. Even then, I suspect that most high-end audio reviewers would find some way to weasel word their evaluation so as not to upset the high-end apple cart. So keep listening to your tube preamps if you are happy with them and avoid any new solid-state preamp that cribs Dans design, or heaven forbid, goes beyond even what Dan has done with the SCPA 1. You will not want to know the degree of damage being done to the audio signal by those other preamps, especially if they cost two to six times what the SCPA 1 costs.
How do I know Dans SCPA 1 is right and the others are not? All you have to do is hear it one time and youll understand. The SCPA 1 is not manufacturing detail, it is not homogenizing detail and it is not adding harmonic distortion to the audio signal. The SCPA 1 is just passing what is present in the recording. The other preamps are clearly squishing things together and obscuring sounds that are unquestionably present in the recording.
The SCPA 1s treble equals or exceeds the most neutral treble Ive heard in any audio component. It isnt romanticized, it isnt rolled off, it isnt harsh, it doesnt have added harmonic content, and it doesnt shimmer too much or too little. The treble does not "sound like solid state" nor does it "sound like tubes." The top end has no sound of its own. This is the standard to judge other components against if you seek accuracy and shun inaccurate audio components. For the first time in my listening experience I found myself thinking: "This must be what is actually captured in the recording." There is no sound to the treble. It doesnt sound rich or thin, cold or warm. It doesnt sound gritty or sweet, resonant or dry. None of the adjectives used to describe the sound of tube or solid-state treble fit the SCPA 1.
The SCPA 1 reveals recordings for exactly what they are. You hear absolutely everything. Each track of Willie Nelsons Across the Borderline was recorded in different studios around the world. Previous listening to this recording on my reference system revealed some small differences in the sound from recording studio to recording studio. Yet if you play this recording on the SCPA 1 and the track to track differences are like opening a door and walking into a completely different room (or studio in this case). Sonic differences from track to track go from "audible" on the best audiophile preamps to "palpable" on the SCPA 1.
I hate to use "palpable" in this review because it is being overused in audio reviews these days. However, there is no other word to use that conveys what the SCPA 1 achieves. Other reviewers seem to be using "palpable" to describe sound that is awash with added harmonic distortion, thick, overly rich and syrupy, not particularly transparent. That doesnt represent what is recorded in most cases. There is a tendency for audiophiles to go for a sound that has certain characteristics they read about in the audio press all the time, rather than to go for hardware which is faithful to what is actually present in the recording. Its the difference between a "digitally enhanced" photo of a beautiful island beach and actually being on that beach yourself. I cant wax rhapsodic enough about a component that is so utterly revealing and so completely absent of the usual audiophile characteristics. All I can say is that the SCPA 1 gives you exactly what is recorded, at least as well as can be done at this moment in time. There isnt much cache in statements like that. Audiophiles seem, in most cases, to want stimulating, attractive, almost sensual descriptions of a components sound to get them interested in what might be their next purchase. Thats a shame, because the SCPA 1s kind of sound is the real deal, but you cant get all gushy about it.
The reduction in noise level alone, compared to tube preamps, is stunning. To then hear the SCPA 1s incredibly fleet-footed navigation of every complex nuance of every sound in every recording, compared to the tube preamp sound that lacks articulation but which is revered in the high-end press, you have to wonder what the audiophile presses agenda really is. Frankly, I think theres an awful large percentage of audiophiles who are afraid of or are intimidated by the real sound of recordings, so they hide the music behind systems that alter the sound of the recordings to make the sound "better."
Ive been looking for a solid-state preamp that does what the SCPA 1 does for a long time. The ones Ive heard havent satisfied me. I have been using a tube preamp for want of a solid-state preamp that was without the usual solid-state sound characteristics. The SCPA 1 is the first solid-state preamp Ive heard that does what Ive been looking for.
What it does -- 5.1 music
DTS music CDs were elevated several steps up the ladder by using the SCPA 1 as a precision channel-balance control in conjunction with a conventional surround processor. I used a six-channel 1kHz test tone to precisely set the level for each channel. The multi-turn precision volume controls on the front of the SCPA 1 were used to bring each channel to precisely the same level. This eliminated about a 1.7dB spread between the channels, the best I could achieve using the 1dB steps in the surround processor.
Playing the DTS CDs I was most familiar with, Stings Ten Summoners Tales, Alan Parsons On Air, The Mavericks Trampoline, and Brian Wilsons Imagination, I explored the overall sound I could achieve with the surround processor by itself. Once I was completely familiar with that sound, the SCPA 1 was added. The improvement with the SCPA 1 was quite clear but not huge. Primarily, the soundstage was more dimensional and less contained within the walls of the listening room. Additionally, placement of sounds within the room, when two or more loudspeakers were used to position a virtual image in space, was perhaps the largest single improvement made by the SCPA 1. These virtual images were more solid and identifiable as being located at a specific point in space than could be achieved with the surround processor alone. Sound quality was essentially identical to whatever the surround processor outputs. The SCPA 1 cannot make sound any better than that produced by the surround processor when it feeds the SCPA 1. Inserting the SCPA 1 with no balance adjustments was as inaudible as inserting another box in a signal path could possibly be. Only when I started moving the balance controls could I hear the SCPA 1 doing anything to the signals delivered by the surround processor.
What it does 5.1 movie sound
The results here are about the same as those noted when playing DTS music CDs; however, the audibility in movie soundtracks is somewhat different. Dialogue did not seem to be affected much. Interestingly, high-energy bass impacts seemed to be driven with more authority from the SCPA 1 than the surround processor could muster on its own. Subtle spatial environments, like outdoors with blowing leaves, or the resonance of a large indoor space, or the sound of people inside their living room, carried a subtle edge in reality through the SCPA 1. It wasnt anything you could specifically identify, just an overall feeling that the SCPA 1-supplied signal was slightly more convincing. Like the music CDs, events placed anywhere in the room, other than at speaker locations, were more convincing. The choice of whether to use the SCPA 1 with movies is a simple question if youre a gotta-have-it-all kind of home-theater enthusiast and the $2700 price is no big deal; by all means, you should have an SCPA 1. However, if you are budget and complexity conscious and can live without the last word in performance, pass on the SCPA 1 and keep your fingers crossed that something that sounds this great will come built-in to your next surround processor.
Closing the door
Adding the SCPA 1 to the system enhanced both music and movie DVDs; however, current consumer hardware is not configured to make the most of a superior six-channel component like the SCPA 1. Namely, the signal from the surround processor would be much higher in quality if all of the internal level-control circuits in the surround processor were eliminated, leaving all the level balancing to the SCPA 1. This would make a medium-to-large positive impact on sound quality of reproduced surround sources. Pro-audio users are likely to be able to make more use of the capabilities of the SCPA 1 than most home-theater enthusiasts; however, home-theater perfectionists will be quite happy with the incremental balance improvement the SCPA 1 can deliver. While Im not going to keep the review sample, I probably would have done so if it had an additional four or five stereo inputs, and the ability to switch to any of those. That added flexibility would have made the SCPA 1 a first-class stereo preamp with the added ability to integrate 6-channel surround into the music system without having to move interconnects.
As it exists today, the SCPA 1 will have a limited audience among consumers, but if you are one of those, the addition of an SCPA 1 will move your system a step closer to the best it can be. Pro-audio applications seem tailor made for the SCPA 1 and indeed, Dan Banquer is hard at work on adding balanced connections to make the SCPA 1 a true "Pro" product. As you can probably tell, this product has set a new high-water mark in my experiences with preamps. High fidelity is something for lesser components. The SCPA 1 is the first true-fidelity preamp Ive had the opportunity to audition. You dont get to hear products like this very often. I only wish the SCPA 1s features complement made it an attractive replacement for my existing stereo preamp. I could then feel no remorse about dumping my existing preamp and moving on to an SCPA 1-based system for stereo music, surround music and movies.
All Rights Reserved