PrimaLuna DiaLogue Three preamplifier
At what point does a domestic audio product cease to be an appliance and assume a loftier place in one's home and heart?
We all can agree that a Bose Wave CD player sits at one end of that continuum, a Koetsu Jade Platinum phono cartridge at the otherbut what of all the products in between? Scarcity, mode of manufacture, appearance, even sentimentality ("This is just like the one my father used to have!")each plays a role, but there's no doubt that price tops the list: The more we pay, the more we love (footnote 1).
If we remove price from the equation, what then? Is sheer quality enough to tip the balance? Given the availability of audio goods designed in America or Europe and manufactured in the Far East, the answer may already be at hand: Although hand-wired vacuum-tube electronics have long been among the most cherished audio heirlooms, those sorts of thing are now available at popular prices, as the saying goes.
Consider PrimaLuna, who design preamplifiers, power amplifiers, and integrated amplifiers in the Netherlands, and manufacture them in their own factory in the People's Republic of China. Far from being just a me-too maker of undistinguished gear orworse stilla forger of other people's designs, PrimaLuna has impressed me and other reviewers with their innovative circuits and very high build quality, not to mention a level of performance that, nuances aside, can be summed up in three beautiful words: classic tube sound. Thus, when John Atkinson asked me to audition their new top-of-the-line DiaLogue Three preamplifier ($2599), I was, as they say, all over it.
The first thing I noticed about the DiaLogue Threebefore the nice paintwork, before the point-to-point wiring, before the soundwas its considerable weight: 53 pounds of iron, steel, and copper, not to mention all those vacuums. This preamplifier weighs half again as much as some of my favorite tube power amplifiers, and three times as much as my dog.
That's because the DiaLogue Three is designed and constructed as a dual-mono preampall the way through, including the power supply and, unusually, the mains transformers. Said trannies appear to have been made specifically for the Three, and are protected with a circuit that detects excess heat and temporarily interrupts the primary feed, should things require cooling down. Shoppers in hell, take note.
The DiaLogue Three is housed in a steel chassis whose shape also calls to mind that of a classic tube amp. A vented transformer cover towers over the rearmost portion of the low-slung surface, the latter interrupted by six tubes: two rectifiers and four dual-triodes. The tubes are protected from the user, and vice versa, by a removable cage shaped like a roll-top desk's most distinguishing feature, and the front of the chassis is fitted with a modestly sized faceplate. The latter is aluminum alloy with a satin finish, while the remainder of the DiaLogue Three is painted with five coats of hand-rubbed blue-gray lacquer. (Black is also an option.)
The preamplifier circuit is straightforward: In each channel, the line-level input signal is conducted, by means of a shielded cable, to the signal grid of a 12AU7 dual-triode tube, the two halves of which are operated in parallel. The ganged plates of that tube are tied, via a Solen capacitor, to the input of a motorized Alps Blue Velvet volume pot, the output of which is sent to the signal grid of a second 12AU7, also operated with its two halves in parallel. The plates of that tube are capacitively tied to the output jacks . . . and there you have it. Except for that very last connection (the printed circuit board for the power supply is also home to the chunky Solen signal-output caps), the preamp section is hand-wired, point to point, with liberal use made of nice-looking ceramic terminal strips, which are cemented to the inside of the chassis.
The DiaLogue Three's power supply, which is constructed using both point-to-point wiring and the remainder of that PCB, uses a single 5AR4 tube for the rail voltages of each channel. Filament voltages for the rectifier tube are supplied by dedicated secondaries of the mains transformers, while full-wave rectifiers constructed with discrete diodes are used to heat the signal tubes.
A modestly sized solid-state preamp board ($199) can be used to change one of the DiaLogue Three's inputs to a moving-magnet phono input, but that option wasn't provided with my review sample. As typically supplied, the preamp's rear panel has five line-level inputs, two system outputs, one tape-monitor output, and pass-through jacks for driving a surround-sound device in a home-theater system. The front panel sports only a volume knob and a source-selector knob, which of course prompted my usual teary whine: I wish the PrimaLuna had a balance control and, especially, a mono switch. I would happily trade that surround-sound thing for the latter.
Included in the price is a remote-control handset that incorporates all the user controls for this and, apparently, all other PrimaLuna productsincluding the Triode/Ultralinear mode switch for the DiaLogue Seven power amplifier. The handset is built into a chunky aluminum-alloy housing of reassuring heft, although a seam between the two halves of the housing had an edgy feel that, in time, discouraged me from using the remote. (I needed the exercise anyway.)
The DiaLogue Three's external fit and finish were very good, and its internal build quality was nothing short of magnificent.
Footnote 1: That, of course, is a sliding scale unto itself: To the consumer of comfortable means, a $500 record player might be little more than a commodity, while the person who's saved for months or even years to buy such a thing would think of it as a cherished possession, and rightly so.