May 2005

The Nearfield
Amplification Delights!
Article By Steven Stone

  Being a professional audiophile requires work. Simply enjoying music you must constantly ask yourself, "Could this sound better?" After nearly 30 years of reviewing I have to admit there are many days when the question "Isn't this good enough?" floats to the top of my consciousness. When faced with the task of tearing up my system to swap out a particular component (especially if it weighs more than ten pounds), my doubts come barreling toward me with the force of a runaway freight train.

The search for musical ecstasy used to keep me on the straight and narrow audiophile path. But recently it's gotten harder and harder to justify searching for something that you've already found. The latest incarnation of my desktop system sounds so good I could happily live with it for years before a niggling audiophile doubt entered my mind. For particulars you need to read The Nearfield #4. So what keeps me going when sonic inertia leads toward a dead stop? Curiosity. The naked need to see what will happen if component A is replaced with component B keeps me in the game.

For this month's intellectual exercise I'll look at something old, something new, and something neo-antique.

The Accuphase P-300 Power Amplifier
Accuphase made the P-300 from 1973 to 1976.  It was their very first power amplifier. The Kensuga brothers, who worked for Kenwood before starting Accuphase, founded Accuphase on the principle of building audio components that sounded musical. In an early product brochure from 1974 they wrote, "We seek, through audio technology, music that's exciting and inspiring, that moves our hearts and enriches our lives." Sounds like an audiophile credo if there ever was one.

I acquired my P-300 from an eBay auction. I got it for a buy-it-now price of $400 plus $50 shipping. After paying for the amp via Paypal, I had the seller ship the P-300 to Accutech repair. They are the authorized US repair facility for Accuphase products. Since the P-300 was made over 30 years ago, it would be silly to assume it would not need refurbishing. It just made sense to have it fixed before I listened to it. Accutech replaced all the power transistors, several capacitors, a display lamp, and one meter magnet. Accutech also cleaned the circuit boards, re-soldered connections, and burned in the amplifier after repairs. They spent over five hours on the amp. The total bill for repair, including shipping, ran $515. 29. When all was said and done I'd spent close to $1000 for an amplifier I'd never heard. That's the cost of impulsive curiosity.

Lest you think me a complete idiot, I had done quite a bit of research on the P-300 before buying a pig in a poke. The specifications and design of the P-300 rival many first class current production amplifiers. The P-300 puts out 150 watts into 8 ohms and 200 watts in 4 ohms using a direct-coupled complementary symmetrical circuit topology for every stage from input to output. Its power supply is spec'ed to produce up to 400 watts of peak power into a 4-ohm load without strain. The P-300 also has a sophisticated speaker protection circuit that engages when it senses a short circuit. This speaker protection circuit also runs a diagnostic when the amplifier is first turned on, so if the circuit senses an impedance load below 1.2 ohms it will immediately turn off the amplifier. According to Accuphase product literature the P-300 also has "closely selected parts" which translates as no electrolytic capacitors with metal film caps used even outside the direct signal path. The only downside of this philosophy is that many of the original Mylar caps may need replacement with modern polypropylene caps.

While the concept of a desktop system didn't exist in 1973 (heck, personal computers didn't begin to populate the world until the late ‘70s), the P-300 has several ergonomic features that make it ideal for a desktop system. Its front panel has individual volume level adjustments for each channel. In addition to a pair of stereo inputs on the back of the amplifier, it has an additional set of inputs on the front behind a spring-loaded panel. With its two inputs and volume adjustment knobs the P-300 can function as an integrated amplifier, so you don't need to use a preamp in the system. The P-300 also has provisions for three sets of speakers (one of which can be used to drive the high-level inputs of a subwoofer), as well as headphones. It has two large back lit power level meters with buttons for three separate meter ranges, a three position output power control with full, 50% and 25% settings, an ultrasonic filter that rolls off the bass below 17Hz at 18dB per octave, and finally a switch to select the front or rear inputs.

So how did my $1000 gamble work out? Better than I expected, actually. The P-300 ranks as one of the superior solid-state class A/B amps I've heard. Is it as good as the Bel Canto EVO-2 (which had been in my system just before it)? Not quite. But when you consider the P-300 is roughly 1/3^rd the price of an EVO-2, its sonic shortcomings become easier to forgive.

The P-300 and the EVO-2 actually have a lot more in common sonically than I anticipated. Both have superb power handling capabilities, with no sense of strain regardless of a source's demands. On my latest live recording of Mozart's Requiem both amplifiers delivered the full power of the orchestra and chorus with aplomb. Dynamic peaks measured by my Radio Shack sound level meter at 92dB a-weighted were no problem for either amp. According to the P-300's meters even at these volume levels the amplifier was only producing 25 watts of peak power.

Both amplifiers also produced a large spacious soundstage with excellent lateral focus. The EVO-2 delivers a more three-dimensional soundstage that rivals many tube amplifiers, especially when it comes to separating out the chorus at the back of the podium. But despite its venerable age and bipolar transistor output stage, the P-300 does as good a job of implying depth as any solid-state amplifier I've had in my desktop system.

The P-300 and EVO-2 amplifiers share the ability to make recorded music sound both natural and involving. Much of this ability can be traced to their extraordinary low internal noise levels. Through either amplifier you can listen deep into the music with little difficulty. Also both amplifiers render micro-dynamics without compression. Music, especially live concert recordings, retains its life and natural contrast.

During long listening sessions the P-300 does produce more listener fatigue than the EVO-2. I chalk this up to the P-300 adding a very slight amount of grain to the texture of the sound. Although these two amplifiers share very similar harmonic balances, the P-300 introduces a bit of electronic texture. This grain can be heard most easily on human voices which seem a tad drier through the P-300.

If you come across an Accuphase P-300 for a reasonable price, and then restore it properly, you will have a very fine amplifier capable of forming the heart of an exceptional desktop reference system. I think I'll keep my P-300 for a while. For more info on the Accuphase P-300 look on Accuphase's website. They have information and the specifications for every product they've ever made.

The Rotel RA-1062 Integrated Amplifier
Desktop systems are an ideal environment to employ an integrated amplifier. Unlike room-based systems that force you to connect an integrated amplifier with either a long speaker cable run or long interconnect run, a desktop system's speakers and sources are so close that the integrated amp placed under your monitor can have short connections to both.

The Rotel RA-1062 replaces the RA-1060 in the Rotel product line. With similar power output, the RA-1062 offers updated cosmetics as well as a new remote control. At $699 the RA-1062 certainly has an attractive price. It also has an almost ideal set of features for desktop use, including a variable output pre-out for a subwoofer, two pair of speaker outputs, three line-level inputs, a real phono input with an RIAA EQ curve, two tape loops, a headphone connection on the front panel, a five position contour switch, and a full-featured remote control. The contour switch has two different bass lift settings as well as a high frequency roll-off, and a high and low frequency combination setting. It works. As to whether you need to use it, that's between you and your music.

Given the Rotel's excellent ergonomics, I had high hopes for the RA-1062. While it proved to be a very competent performer, especially considering its price, its sonics rank substantially below what can be achieved from my reference combination of the Monolithic PA-1 and Bel Canto EVO-2 or Accuphase P-300 power amplifiers.

Even though the Rotel isn't a price-no-object giant-killer, it may well be the 500 lb. Gorilla in its particular price range. Compared with the $750 TEAC AV H-500D integrated amplifier, the RA-1062 emerged as a clear winner. Even though the RA-1062's power rating specifies only 10 watts more power per channel, the Rotel delivers more effortless crescendos. The Rotel also has a noticeably more natural and less electronic harmonic character. Lateral imaging through the Rotel has more precision than the Teac, but neither unit has any semblance of depth or three-dimensionality. The Rotel creates a slightly larger soundstage than the Teac with a tad more precise lateral imaging. Given the choice between these two similarly priced components, the Rotel would be my choice in an instant.

The Rotel's primary sonic faults are of omission. Music certainly doesn't sound bad or harsh through the RA-1062, but it doesn't have the necessary joie de vivre to be completely involving. While the RA-1062 is certainly a step up from an average mid-fi surround sound receiver or integrated amplifier, it still falls slightly short of what I require from a first-class desktop system. Its sonic sins culminate in a less than involving musical experience. While it has no glaring flaws, the Rotel RA-1062 doesn't quite deliver enough detail and dimensionality to qualify as high-end sound. Too bad, since its ergonomics are so well conceived for desktop use.

Sound Valve 100 SE
Never have I received a product for review with so little information accompanying it. Even Sound's US distributor Axiss, who also handle Accuphase and Air Tight, had little in the way of additional technical info. I do know that this is a single-ended integrated amplifier that uses one 12AX7 and one 6L6 tube per channel. It is rated at 8 watts per side, has three line level inputs and one tape loop. Front panel controls consist of a three way input selector, tape monitor on/off switch, volume control, on/off switch and something labeled "Hujon" which seems to be some sort of presence control. Priced at $1500, the Sound Valve 100 SE qualifies as an affordable desktop integrated amp for someone who longs for that single-ended tube sound.

Fit and finish on the 100 SE ranks about on par with Dyna Stereo 35 SCA if the Dyna had a thicker faceplate. The paint job on the Sound's transformers doesn't inspire confidence. They have enough runs to make for a successful baseball team, but not necessarily a carefully constructed amplifier. The front panel looks good, especially with its smoked plastic faceplate that lets you see the tubes' glow.

For desktop use the 100SE's ergonomics are barely adequate. The lack of any preamp output coupled with only one set of speaker outputs makes using a subwoofer difficult. You could connect a second set of speaker cables to a subwoofer's high-level inputs, and depending on the subwoofer's and main speaker's combined impedance have it work out fine, or not. I got around this problem by using the 100SE as a power amp with the Monolithic PA-1 serving as a preamp. I suppose if you don't want to use a subwoofer the 100 SE could be used alone, but given its limited power output, a subwoofer is recommended.

Once installed the Sound Valve 100 SE proved to be an impressive sounding piece of electronics. Despite its low rated power it was able to drive both the Reference 3A Dulcets and the Ariel Acoustic model 5s to reasonably satisfying volume levels before coming unglued. While the 100 SE doesn't have the sense of ease at high volumes of the Bel Canto EVO-2 or Accuphase P-300, it doesn't sound strained, merely compressed. The differences between a forte and a triple forte through the 100 SE are moot at simulated concert hall volume levels.

The 100 SE excels at creating a three-dimensional soundstage. On my live concert recordings every instrument could be found in exactly the right spot on the stage. Not only does the 100 SE correctly capture the depth of the concert stage, but it also does a superb job of depicting the back and sidewalls of the hall. On well-recorded recordings with proper dimensional cues, the 100 SE can make you stop anything you're doing to pay attention. Its three-dimensionality can be totally absorbing.

Compared to the dynamic precision of the Accuphase P-300 and Bel Canto EVO-2 amplifiers the 100 SE appears rather loose and sloppy. This amp apparently lacks the control and damping needed to keep a speaker's drivers from traveling a bit further than they should. The sonic effect reminds me the affections of a large friendly sheepdog — wet and overly-rambunctious.

As you might expect from such a small single-ended tube amplifier, the 100 SE has issues at its frequency extremes. Its high end is slightly soft while its bottom end has a bit of extra mid-bass roundness and bloat. These harmonic nonlinearities give music a more euphonic lilt. While not unpleasant, it sacrifices some accuracy for implied musicality.

While the Sound Valve SE 100 has a decidedly seductive and relaxed musical presentation, unless you employ speakers with at least 91dB efficiency you will find it somewhat underpowered with less than completely satisfying dynamics for desktop listening.  While I loved the Sound Valve SE 100's seductive sonority, after a couple of days I longed for a bit more muscle and dynamic brawn in my system.  The Sound Valve SE 100 certainly has a wonderful sound: I just wish it had a bit more of it.

Next month I'll look at a two compact monitor speaker systems from two well-known manufacturers. See ya then. In the meantime bonbons and brickbats can be sent to me via e-mail.