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Product Review - Wright WLA-12A Tube Preamplifier & Parasound P/LD-1100 Solid State Preamplifier - May, 2000

Jason Serinus

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Wright Sound Company, 3516 South 262^nd Street, Kent, Washington 98032; Phone 253-8959-3592; Fax 253-850-1859; Web http://www.wright-sound.com	Parasound Products, Inc., 950 Battery Street, San Francisco, California 94111; Phone 415-397-7100; 800-822-8802; Fax 415-397-0144; Web http://www.parasound.com

A TALE OF TWO PREAMPS

HOW I OVERCAME IMPEDIMENTS

AND GAINED A GREATER APPRECIATION

FOR WHAT'S LESS AND WHAT'S MORE

The Wright Sound Company WLA12A Line Drive Tube Preamplifier

Specifications:

Tubes: 2 x 6SN7, 1 x 6EM7, 1 x 6X5

Polarity: Inverting

Frequency Response: Better than 20 Hz to 20 kHz , plus/ minus 1 dB

Very Linear 6 SN7 voltage and driver stages

Distortion: Less than 0.4 percent total harmonic distortion

Input Impedance: 100 kOhms, nominal

Output Impedance: 2 kOhms, nominal; will drive loads down to 600 ohms with some loss of output level

Voltage Gain: 12 to 20dB, switchable on back

Noble Audio Mastering pots

Hovland Musicaps© in line stage

Worldwide voltage switch

Tube rectifier and regulation for truly quiet operation

Output Level: 1 volt PP nominal; will drive up to 20 volts PP

Stereo-mono-stereo reverse switch

Output level control: 0 dB to - 10 dB, plus Full Mute

Tape record and playback compatible

Weight: 7 lb.

Size: 6 x 10 x 5 inches

Warranty: Limited one year parts and labor, tube warranty 90 days.

MSRP: $695 USA

The Parasound P/LD-1100 Line Drive Solid State Preamplifier

Features:

Dual mono circuit designed by John Curl

Six line level inputs

Direct coupled -- no capacitors in signal path

Complementary hand matched MOSFET drive circuit

100% pure Class A circuitry, 44,000 µF power supply filter capacitance

Separate glass epoxy circuit boards for each channel

High current dual mono headphone circuit

Tiffany-style gold plated RCA jacks

Motorized volume control with LED indicator

Fully remote controlled, including input selection u External infrared remote input

Removable IEC AC cord

12 volt DC automatic turn-on trigger output

2 rack space mounting adapter available

Specifications:

Frequency Response: 5 Hz - 135 kHz, +0/-2 dB, full output; 5 Hz - 100 kHz, +0/-2 dB, full output -6 dB

Total Harmonic Distortion: 3⁄4 0.005%, 1 kHz; 3⁄4 0.007%, 20 kHz

IM Distortion: 3⁄4 0.004%

IM: unmeasurable

Maximum Output: > 10 V before clipping

Input impedance: 30 kOhms, ± 5%

Output impedance: 60 ohms

Recommended line load: 600 ohms

Recommended headphone: 8 ohms

Input Sensitivity: All inputs 150 mV, ±5%

Maximum Input Level: 10.5 V before clipping

S/N Ratio: > 102 dB, A-weighted, full output; 93 dB, A-weighted, full output -6 dB; > 84 dB, unweighted, full output; > 81 dB, unweighted, full output -6 dB

Maximum Hum: > 0.05 mV, full output; > 0.08 mV, full output -6 dB

Crosstalk: > 100 dB, < 10 kHz, full output; > 96 dB, 20 kHz, full output; > 90 dB, 20 kHz, full output -6 dB

Channel Balance: 3⁄4 0.3 dB; 3⁄4 1 dB, -60 dB

Dimensions: w 171/4" x h 3" x d 16", h 35/8" with feet

Weight: 16 lb.

Size: 6 x 10 x 5 inches

MSRP: $850

Warranty: Ten years parts, five years labor; two years p/l for moving parts. Original owner only when purchased from an authorized Parasound dealer.

REVIEW SYSTEM:

Michael Green Chameleon III tunable speakers (modified with Nirvana hook-

up wire and Scan Speak 2905/9700 tweeters);

Hsu HRSW12V powered subwoofers (stereo pair);

PASS Aleph 5 60W pure Class A poweramp/Bruce Moore Dual Seventy

Wideband Tube Poweramp;

Bruce Moore Companion III tube preamp;

Theta Gen. 5A single-ended DAC;

Genesis Digital Lens with BNC in and out;

Audio Alchemy DDS-Pro transport;

PS Audio P300 Power Plant;

AQ Dragon II speaker cable to the Chameleons;

AQ Clear II speaker cable to the Hsus;

Nirvana interconnect from amp to preamp;

AQ Diamond II co-ax interconnect from Hsu amps to preamp;

Tara Decade interconnect from preamp to Theta DAC;

Nirvana digital (BNC) interconnects from Theta to Lens and Lens to transport;

Power cords by MIT, Synergistic, Harmonic Technology and XLO;

Michael Green Deluxe Ultrarack and Basic Racks; MG audiopoints and room treatment; Black Diamond Racing Cones; inner tubes, maple cutting boards and bags of sand, homemade bass traps; Shakti stone and many Shakti On-Lines; Bedini Ultraclarifier, Audioprism Stoplight and Blacklight

Introduction

Some months back, my helluva guy fellow reviewer, Paul Knutson, asked me if I wished to review the Wright WLA12A Tube Preamplifier. Since the diminutive, lightweight $695 Wright sells for a significantly lower price than my far larger, heavier $3000 Bruce Moore Companion III Tube Preamp, I realized that, unless the Wright was the biggest steal on the market, I would have to adjust my expectations in order to give the it a fair evaluation. Obtaining a second preamp in the Wright's price range, and performing a comparison between the two, seemed the most responsible way to proceed.

At the same time as Paul and I were working out review logistics, I was setting up a Bay Area Audiophile Society demonstration of the new Perpetual Technologies P-1A/P-3A combo. (Expect Paul's review in the fall). Given that Perpetual Technologies' founder, the estimable Mark Schifter, was flying into San Francisco from Colorado especially for the demo, he decided to lighten his load by asking Parasound Products of San Francisco to supply the demo amp, preamp, and transport. Parasound brought along its P/LD-1100 Line Drive Solid State Preamplifier, an $850, John Curl-design that, despite being on the market for a number of years, has been passed up by reviewers in favor of its now-discontinued big sister/brother. The opportunity to compare tube and solid state products of roughly the same price point (especially if you consider the $80 cost of the replacement 6SN 7GT tubes I eventually used for the Wright review) was too enticing to pass up. Upon broaching the subject, Parasound graciously supplied me with a brand new review sample.

The Drama Unfolds

No one who has received multiple shipments of high-end gear will be surprised to learn that UPS did not treat the Wright shipment as though it were a gift from the Gods. When Paul removed the preamp from its damaged carton, he discovered that the supplied 6SN 7GT tubes had received the kind of jolt that made him uncomfortable turning the unit on while he was in the same room. After replacing the traumatized stock tubes with Sylvania JANCHS 6SN 7GT short bottle tubes (approx. $20 apiece), he brought me the unit.

The Wright comes with a non-removable, two prong, non-polarized, lamp cord-style power cord. With the help of a polarity tester, we determined the best way to plug the unit into my P300 Power Plant. We also discovered another use for the “green pen” CD Stoplight (which I use on all my CDs): it's a great tool for marking polarity on plugs.

Paul told me nothing about the little switch on the back of the preamp. In fact, he forgot the instruction booklet entirely. Acting on blind faith, we connected the Wright to my Pass Aleph 5, made sure nothing would blow up when we turned everything on, and bid each other a fond farewell.

Not for long, though. To put it simply, the Wright preamp sounded lousy. No midrange to speak of, and hardly a semblance of bass. Even on a simple voice/piano recital, the lower notes of the piano seemed less substantial than claims that any particular bag lady is really an incarnation of the Virgin Mary. Calls to Paul, and then to Mom and Pop Wright, revealed that, even if I had been given the instruction booklet and/or gone to the Wright website, I would not have been informed that this preamp inverts polarity. Not right, folks. So, the first step was to switch around my speaker cable leads.

(You might ask, why not simply flip the polarity switch on your Theta DAC? Some designers counsel against this practice, stating that it adds an extra circuit to the signal path).

Alas, the much-anticipated dramatic improvement failed to occur. When Paul made his second pilgrimage across the San Francisco Bay to Serinusland, he brought along, not only the much-lamented manual, but two Sylvania tall bottles ($40 apiece). These did improve the sound somewhat, but not enough to convince me that I could say good things about what I was hearing.

Then Paul said, “listen to this.” First turning the preamp's quite-vocal Mode selector switch to mute, he bravely disappeared behind my rack, venturing into the black hole from which several former high-end reps have yet to reappear. With the faith of a true hero, he lingered long enough to flip a previously unidentified, equally vocal switch. Voila, or rather CLICK, a veil lifted, enough to convince me to ask the pallbearers to remove the casket they had just delivered for the nearly departed Wright.

Exclamations of “Whatdja do?” revealed that Paul had initially lowered the voltage gain by 8 dB by flipping the Gain switch at the back of the preamp to the low setting. Doing so inserts a resistor in the signal path. With low gain, the initial volume of the preamp is lowered, and one has more flexibility in volume adjustment with the unit's detented volume control. However, prior experience with such an option on both the Bruce Moore Companion III CD1 input and the Audible Illusion's Modulus 3A CD input has convinced me that putting extra resistors in the signal path tends to dampen highs, decrease dynamics, and in general suck life out of sound. Unless one needs significantly extra gain at the upper end of the volume control, which may be called for by some analog set-ups, a far better solution is to either live with the higher gain or ask the manufacturer to readjust the dB increments on the detented volume controls. This is what several of my Audible Illusions-owning friends have done, and what I have done with my Bruce Moore preamp.

With the switch flipped high gain, "Dusty" Knutson emerged victorious. Yes, the difference was major. Convinced that the world was now a better place, he swept away the dust the pallbearers had left, and made his way back to the safe confines of San Francisco . . . but, a bit too soon.

Impeded by Impedance

I then assembled my trusty pile of test CDs, a pile that grows as I continually encounter and review new recordings. I demagnetized, listened, noted, switched, breathed, fussed, pondered, bemoaned, belabored. I called Paul, consulted psychics, prayed to Buddha, cursed the universe. Nothing would make the Wright sound right.

I then tried the Parasound. As with all equipment, I thoroughly broke in the unit, played demagnetizing and break-in tones, and gave my cables adequate time to settle in. The difference between the two preamps was so great that the results seemed unfit to print.

Upon phoning our illustrious founder/owner/editor/proprietor, John Johnson, to tell him I was throwing in the towel on the Wright, he asked about the input impedance of my Pass Aleph 5. “10 kOhms in single-ended mode, 25K in balanced mode, I reported upon checking the manual. And since these two preamps are both single-ended, 10 kOhms is what it is and will be. “That's much too low for a tube preamp with such a diminutive power supply as the Wright's,” he replied. “No wonder it doesn't sound good. You've got to use a power amp with a high input impedance before you can get any sense of what the unit sounds like.”

Happily, I had on hand a review sample of the Bruce Moore Dual Seventy Tube Power Amplifier. The input impedance of this unit is 100KOhms, ten times greater than the Pass's. While replacing the Pass with the Moore didn't make the Parasound solid-state preamp sound very different, it totally resurrected the Wright. Besides an annoying, ever-present hum, which careful tube matching can hopefully eliminate, this little preamp finally came into its own.

HIGH-END LESSON NUMBER 5,332. Careful system matching is essential with tube preamps.

Good-bye to hours of listening and a page of notes. (When I figure out all the time I have spent reviewing these two preamps, I'm probably going to make $1/hour). Time to start anew.

Feature Comparisons

While both preamps offer two main outputs, a separate tape output, a tape input, plus four other inputs, the Parasound also offers a “Direct” input jack. Since this jack feeds a separately switched line level input boasting the most direct signal path to the power amplifier, I used it exclusively when testing the Parasound.

The Parasound also has remote control, which I didn't use. There was no sonic reason for not using it; I simply am accustomed to jumping up and down like an idiot every time the volume needs adjusting. Volume adjusting is in fact easier on the Parasound, because the volume control is not detented. The issue I have encountered on other preamps of wanting to set the volume to the unavailable level between two clicks did not have cause to surface here. For ease of operation alone, the Parasound preamp is a winner.

I had plenty of time to perform my comparisons, because the Bruce Moore Companion III Preamp I've grown to love was stuck in the shop having the gain on its detented volume controls adjusted. I played the selections I was reviewing first on the Parasound, then on the Wright. Since the Parasound offers a detachable power cord – yet another plus – I auditioned it both with a Synergistic Master Coupler and the “stock” power cord that comes with the unit (allowing time for break-in, of course). Parasound assured me that this cord, which is hand-soldered, is a step above most “stock” cords. To put it simply, they are correct. Once broken-in, it is still a step above the basic, non-polarized power cord that the Wright family supplies. Ah yes, it's polarized. Yet another point for the Parasound.

Doing Right by the Wright, while Pairing with the Parasound

I used the same selections when reviewing both the Wright and Parasound preamps. Comparison included an extended listening period with the new DG recording of Dvorak's Symphony No. 9 (“From the New World”) conducted by Claudio Abbado, which I was reviewing at the time.

First up were various tracks from J.S. Bach's well-loved Brandenburg Concertos, played on authentic instruments by the Berlin Academy for Ancient Music. This is no staid academic performance. Originally reviewed with the fabulous $6,550 Bruce Moore Dual Mono Preamp in the signal path, these two discs offer a veritable riot of color and sound, qualifying as among the best, consistently engaging recordings of the Brandenburgs on the market.

Though the Parasound lacked an ultimate sense of instrumental color, color was nonetheless present. Everything sounded a bit toned down and muted compared to what I'm used to hearing, however. Images were distinct and well defined – a definite plus. But I missed the push and splatter of the authentic instrument horns on the first Concerto's first movement. (Once you hear this on a great system, you'll know what I'm talking about; many older instruments sound less smooth than those employed in modern orchestras. This can give them the extra bite that makes for a lauditory auditory experience.) I also noted a lack of vibrancy and brilliance to the highs, and a lack of air around images. By comparison, I found the highs on the Wright, though also lacking ultimate brilliancy and sheen – I am not talking about sharpness or artificial, hard-edged stridency here – seemed more convincing. I especially liked the sound of harpsichord, even though it, like everything else, had less body and substance than I would have liked. In fact, I found the Wright more transparent and exciting on this music. The Wright's transparency added a sense of depth that I had not previously heard with the Parasound. I also experienced what seemed like a wider, more involving soundstage, and a semblance of air around instruments. As I proceeded to do my comparisons, however, I consistently wondered if this was due in part to the fact that the Parasound seems to “fill in the spaces” more with midrange substance, while the Wright can sound a bit lean.

Next came the 24-bit Sony disc of mezzo Susan Graham's superb La Belle Epoque recital of songs by Reynaldo Hahn, with Roger Vignoles at the piano. Having just had the privilege of sitting in the first row for Susan Graham's Berkeley recital, as well as hearing her warmups from farther back in the empty house, I can state with confidence that I know how marvelous she sounds in real life.

The body of Graham's voice and the low notes of the piano came through wonderfully on the Parasound. But again, everything was a bit muted, with the ultimate life of the music diminished. There is a passage at the end of Hahn's A Chloris where Graham executes an exquisite, perfectly controlled dimuendo on the world “ambrosia,” her voice sinking deeper into her heart. While I could hear this effect on the Wright, it made much less impact than on my $3,000 reference Moore (or on the $1,650 Bruce Moore Companion II-b I originally owned – see review Secrets published recently). And while the highs were more vibrant on the Wright than on the Parasound, I again experienced a lack of brilliancy which felt like a mild scrim had been thrown across the stage. Within the Wright's diminished tonal window, however, timbre seemed true.

I first heard the superb final “Blues No More” Track of the JVC-XRCD release of Terry Evans' Puttin' It Down at the San Francisco Hi-Fi Show a few years ago, and immediately fell in love with his singing, the arrangement, and Ry Cooder's guitar. This is a great recording, with lots of space, fine percussion, and much musical room to breathe. It's one I use consistently when reviewing equipment.

With the Parasound, cymbals lacked spark, and the beginning strums of the electric guitar lacked visceral impact. Ultimate slam was also missing from the drums, and bass lacked the clarity I was used to hearing. The recording still came across as superb, but it was not as involving as when heard through more costly preamps. I especially wanted more control on the bass. But this is something I wanted from both the Wright and Parasound preamps. With both units, in the range where my room has problems controlling bass, those problems became more pronounced.

My experience with the Parasound remained unchanged while auditioning both the DG, reverse polarity Boulez recording of Mahler's Symphony No. 6 and the head-over-heels superior sounding Reference Recordings disc of Argento's Valentino Dances (what a stunner). Though drums were round and full, everything again seemed a bit damped.

While each preamp seemed plagued by noise floor issues, which created a scrim on the sound and a lack of brilliancy on the highs, the greater transparency and air offered by the Wright led to a more involving presentation. Even though it hummed excessively (though not annoyingly), and did not “fill in” the midrange as well as the Parasound, I found myself listening to it longer before switching between selections. My God, I was actually enjoying myself! When it came time for me to meet a CD review deadline by comparing recordings of the Dvorak Symphony No. 9, I chose the Wright for my work.

I spent many hours using the Wright preamp to compare the Abbado DG and Harnoncourt Teldec recordings of Dvorak's Ninth Symphony, especially when I threw a historic 1929 Erich Kleiber recording in for further comparison. I could never get the volume setting exactly right, wishing to place it mid-way between two of the detents. (Nothing new; as discussed above, this situation is common with detented volume controls. It seems manufacturers set them this way because analog setups with phono preamps often need significantly higher gain than other components. For those owners for whom this is not an issue, having the volume control detents readjusted by the manufacturer is definitely the way to go.)

The Wright would get a little noisy in the loudest passages, moreso than the Parasound (I never felt the Parasound straining). I also missed the rich color and impact fullness of the double basses; enough of it is there to satisfy, but the Wright is ultimately better on highs than on lows. The exciting thwacks on the drums were also undeniably audible (far better captured by Teldec than DG). Most importantly, the musicality of the symphony came through. All in all, though lacking the fullness, clarity, visceral impact, and vibrancy of the sound of higher-priced equipment that is worth the money one pays for, the Wright was still musical and involving. And this, ultimately, is what matters.

Final Thoughts

There is an adage in the audiophile industry that, above a certain price point, one receives diminishing returns for the amount one shells out. My experience with these two preamps has convinced me that, for under $1000, one can definitely obtain a musically rewarding preamp that can bring much pleasure. If, however, one is willing and able to pay the extra bucks, and already possesses the quality of equipment and cables that warrant spending more on a preamp, the rewards are great in the multi-kilobuck categories.

A case in point. Over a week after completing my preamp comparisons, my Bruce Moore Companion III made its way home. Even before the new resistors which control volume gain had broken in, the differences between it and these units was apparent. I can best describe these differences by offering an analogy. Have you ever experienced the live sound of a full symphony orchestra, heard from a good seat, after previously only having heard symphonic music reproduced on a mass market, run-of-the-mill home system? That's the difference in impact between a worth-the-money $3,000 unit and these two particular preamps that cost under $1,000.

Be that as it may, these lower cost preamps offer many rewards. The remote controlled, detachable power cord, non-detented volume control, solid state Parasound offers far more flexibility and ease of operation than the Wright, and may prove the superior choice when matched with the overly bright components one too frequently encounters in this price range. It also has a much better warranty, and lacks all those noise, burnout, heat, and matching problems one can encounter with tubes. (Solid state is far better suited for tight quarters, I might add, because it won't heat the room nearly as much.) The Wright, however, when CAREFULLY matched with the right components, offered at least one listener a more rewarding and inviting musical experience. Just remember to choose a power amp with a high input impedance, i.e., 50 kOhms or above.

The reader whose first priority is music would prove wise to audition both these preamps, as well as others in their price range and above, for example, the much-touted $1,250 Adcom GFP-750 preamp. Take these units home, give them time to settle in, and hear for yourself which one has you coming back for more.

- Jason Serinus -

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