Quad 405 power amplifier J. Gordon Holt and the 405 Mk.2

J. Gordon Holt reviewed the Mk.2 version of the 405 in April 1983 (Vol.6 No.4):

Warning to purists: Despite certain qualities about Quad's ESL-63 loudspeakers that you will probably like, Quad equipment is not designed primarily for audiophiles, but for serious-music (call that "classical") listeners who play records more for musical enjoyment than for the sound. Quad's loudspeakers do not reproduce very deep bass and will not play at aurally traumatizing volume levels, and Quad's preamplifier is compromised through the addition of tone controls and filters, all for the purpose of making old mediocre, and/or worn recordings sound as listenable as possible.

The Acoustical Manufacturing Company, better known as Quad, is one of the few remaining in the world that still view high fidelity as a service to serious music rather than an end in itself. Their products are designed to meet the needs of classical-record collectors who frequently play old, technically primitive (or inept) recordings for the music or the performance rather than for the sound.

Despite all the improvements in recorded quality that we have witnessed in recent years (with even RCA and CBS getting in on the act), audiophile-quality recordings are still very rare. The variety of fare represented on good recordings is exceedingly small, and the performances themselves range from good to ho-hum. To quote one observer, "Good sound and inspired performance seem mutually exclusive." Amen! Dedicated audiophiles would rather listen to silence than bad sound; record collectors will put up with awful sound if the music is worth listening to.

Quad's view is that a system should be able to reproduce everything of value that is on a recording, while minimizing the irritations of the average (call that "mediocre") recording. Quad's components reflect that philosophy.

Because these were designed as the components of an all-Quad system, I elected to review them as a complete system as well as individually. The units were substituted, one by one, in a system consisting of a pair of Acoustat Four speakers, an Acoustat 200 power amplifier, and a Berning preamplifier. Program sources were 15ips 2-track analog tape, Compact Discs from a Sony CDP-101 CD player, and several of our high-rated cartridges in a modified Rabco arm. The same signal sources were used to audition the entire Quad system.

Model 405-2 power amplifier
"Current Dumping," a Quad invention, uses two output sections per channel—one a low-powered one optimized to reproduce sonic subtleties, the other a high-powered one whose services are called on by the other output section only when the need for brute force arises. We tested an early 405 some years ago but were unimpressed, as its sound was quite dull and, we felt, "slow." The 405-2 sounds like a different amplifier.

Like all European power amps, this one has substantially higher sensitivity than US and Japanese ones. (Sensitivity is the amount of input voltage needed for an amp to produce its full rated output. The US/Japanese standard is around 1 volt; the European standard is half that at 500 millivolts.) Higher sensitivity is not always an asset, because it can effectively raise a preamplifier's otherwise inaudible output noise up to the point of audibility. And since output noise originates after the preamp's volume control, it is unaffected by the setting of that control.

For instance, with loudspeakers of average efficiency, and every preamplifier I had on hand, the 405-2 produced a faint hiss background that was clearly audible in the absence of signal and during the pauses between CD selections. It was swamped by surface noise from even the best analog discs, but with more efficient loudspeakers, or ones having treble peaks, that hiss would have been raised several dB more, to the point of genuine annoyance.

There are two solutions to this: (1) use signal attenuators at the power amplifier inputs, or (2) use the 405-2 with a European preamp, such as the one Quad intended it to be used with, the Model 34. (Construction details for a passive volume control that would serve as an attenuator appeared in Vol.6 No.2.)

Also like most other European power amps, the Quad has no RCA input receptacles. Connections are made via a 4-pin DIN socket. An adaptor cable is thoughtfully provided, but the thought would have been appreciated more if the adaptor cable had not been defective on delivery. The RCA-plug ends were so sloppily wired that the shielding braids were shorting against the Hot terminal in both plugs. It was easily remedied, but an annoyance, nonetheless.

Sonically, the 405-2 presents a generally balanced spectrum but with a trace of lower-treble brightness, a subtle dryness, and a slight deficiency of low-end impact, probably attributable to the subsonic filtering. Imaging accuracy and stability are excellent, while depth reproduction was very good but not superb. Overall, the sound was very slightly dry.

In other words, as an isolated component, this is a very good amplifier but not a hands-down winner. It is handicapped at the outset by its price, the result of its origin in a country where production costs are comparable to ours, plus the markup which must be added when it is imported. And the fact is, the US still leads the world in power amplifiers that offer the maximum quality for the lowest price. The American-made Amber Series 70, for example costs the same as the Quad (granted, with no import duties or distributor markups), and is a better-sounding amplifier despite its lower rated power.

System Sound
After all the positive reviews of the Quad system—34 preamp, 405-2 power amp, ESL-63 speakers—that I have read (particularly in the British press, whose views are generally in accord with mine), I must confess to some disappointment now that I have lived with these components for a while...The system sounded smooth! But while there is no denying the musicality and listening ease of this system, the sound is simply not realistic, nor even a reasonable approximation of that. It is too smooth, too rich, too polite, and while certain instruments—fiddles, for example—are reproduced as well as I have ever heard them, most other instrumental sounds are more-or-less tainted with an almost cloying warmth that not even the Quad 34 preamp's Tilt control can cure. Gone is the bite of the trumpet, the thrum of the cellos, the blat of the trombone, the twang of the piano's upper-bass strings.

I am not speaking here of preferences in reproduced sound, and there are doubtless many people who will like this kind of reproduction. Indeed, it is exactly the kind of sound that many record collectors, given a choice, will prefer to the hyperdetailed renditions of an audiophile-type system. But to take a $3000 speaker system with the imaging and detail of the ESL-63s, and drown those attributes in a sea of haze strikes me somehow as a moral felony.

I love the richness and fullness of live orchestral sound, but I also love the rough edges that much live musicmaking produces, and it is those that I miss in this system. I still have the feeling that the '63s, mated with the "right" electronics, could deliver that level of fidelity without sacrificing their positive attributes (imaging, balance, detail). But I have not heard that sound from these speakers as yet, and until I do I can only say: Audition them for yourself. You may disagree with me.—J. Gordon Holt

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