Jadis DPMC Phono Preamplifier

Joie de Vivre

Equipment report
Categories:
Solid-state preamplifiers,
Phonostages
|
Products:
Jadis Electronics DPMC
Jadis DPMC Phono Preamplifier

Situated in the petite village of Villedubert in the south of France, the Jadis factory is literally far off the beaten track. According to designer JC Calmettes, Villedubert is a wonderful, quiet place, where air, food, and life are all good. It has apparently also been a perfect setting for audio inspiration since Jadis was founded some 31 years ago by JC’s father, Andre Calmettes, and Jean-Paul Caffi. After his father’s retirement 12 years ago, JC has been solely responsible for all analog work. His design philosophy remains the same as that of his father: Offer the customer the most potent emotional experience when listening to reproduced music—and that has meant vacuum-tube-based gear from the beginning. Jadis has stayed small over the years but always focused on the necessary ingredients for success: handcrafted components built without compromise using the best components available. Passive parts are only selected after extensive listening sessions, and in the case of output transformers they are designed and handcrafted in-house to ensure everything’s done right. Jadis has justly earned a reputation for sonic excellence combined with design elegance—a feast for the eyes as well as the soul. Driven by musical passion, Jadis views its designs as the means to transmit that passion to the end user.

It’s been over two decades since I’ve auditioned a Jadis component, so I was looking forward to the experience. The DPMC is the entry-level phono amplifier in a lineup that includes the JP80MC, probably Jadis’ best-known preamplifier. It is described as an ideal means of adding phono capability to any integrated amplifier or line preamp. And initially that’s exactly how I used it, driving it into a line-level input on the PrimaLuna Dialogue Premium line preamplifier. The DPMC has only one phono input and a single output. However, a volume control is provided, and because the output impedance is sufficiently low (less than 1k ohm), it is quite possible to directly drive a power amp, assuming one is content with being restricted to a dedicated analog front end. That option was also explored, by driving the DPMC directly into the Lamm Audio M1.2 Reference monoblocks.

A single large PC board houses both the power supply and gain stages. The power supply is a critical factor in any amplifier design, and especially a phono preamp tasked with amplifying fragile, low-level signals. In line with what has become a common denominator for many successful tube phono preamps, the DPMC incorporates DC filament and regulated plate voltage supplies for the gain stages. The use of a solid-state series pass regulator was adopted by Audio Research as early as the 1970s with the iconic model SP-3, and this approach gained popularity in the 1980s. The DPMC’s star attraction is a tube-based series pass regulator consisting of an EL84 beam power tube and an EF86 pentode. The regulator serves to maintain a stable B+ and reduces AC ripple in the plate voltage of the four 12AX7 dual triodes used as gain and buffer stages, a major plus for any phono preamp. The stock 12AX7 triodes are Russian Tung-Sol reissue types, which Jadis considers to offer the best sound available with regular and stable production.

When I spot 12AX7s in a phonostage I automatically suspect active RIAA equalization. And that happens to be the case with the DPMC. Since an active network uses feedback loops to implement the inverse RIAA frequency response, the overall voltage gain is significantly reduced, making high-gain tubes a prerequisite for such a circuit. To my mind this approach has withstood the test of time, having been embraced by many great designs dating back to the Dynaco PAS-2, Marantz 7, and the early Audio Research and Conrad-Jonson preamplifiers. In the late 1980s, partly based on an irrational fear of any type of feedback, fashion swung away from this traditional implementation toward passive RIAA EQ, which made it possible to use medium amplification-factor tubes such as the 6DJ8. However, as the DPMC amply demonstrates, there is plenty of magic left in the classical approach, especially when coupled with a modern, well-regulated power supply.

The DPMC’s single input is intended to accommodate both mm and mc cartridges. There’s plenty of gain (66dB) to handle even low-output moving-coil cartridges, especially when factoring in the gain of the associated integrated amplifier. The problem, however, is that there is no provision for adjusting the input impedance in order to match the needs of a given mc. The input impedance is fixed at 47k ohms for all cartridge types. I consider this to be a serious limitation as many mc’s work best into an impedance load in the range of 100 to 300 ohms. The impact of an improper loading would most noticeably be perceived in the treble range as reduced damping of treble transients and as brightening of harmonic textures. As a user, be aware that running an mc into this preamp is a bit like playing with fire. The end result may not necessarily be equivalent to lighting a match to a gasoline-soaked treble range, but may in the long run result in listening fatigue. Of course, there are some mc’s that are fairly immune to loading effects. And with certain albums, and on some systems that are tonally laid-back, these effects may not be objectionable.

It so happens that I have a total of seven functioning turntables in the house. Most of these are tangential trackers acquired over a period of several years in an effort to explore a format that is essentially no longer in production. Since some of these tables are outfitted with moving-magnet cartridges, the plan was to listen to several of these “second tier” tables before rotating over to my reference front end, which comprises the Kuzma Reference table, Kuzma Stogi Reference 313 VTA tonearm, and the Clearaudio Da Vinci V2 MC phono cartridge. First in line was a refurbished B&O 8000 outfitted with the superb MMC 20CL moving-magnet cartridge featuring a single crystal sapphire cantilever and a line-contact stylus. Next in line was a refurbished Revox B795 outfitted with an Audio Technica ATOC9ML moving coil. After that it was time for my Sony PS-X600 fitted with a Signet MR5.0ML moving magnet—a musical combination that is well worth pursuing on the used market. Note that the DPMC manual recommends a one-hour warm up. That may be a bit on the conservative side, as about twenty minutes seemed sufficient to smooth out the treble range.

By now, after assimilating listening impressions with three ’tables, I was developing significant enthusiasm for the DPMC, so let me stop to share a few findings. It became perfectly clear that there was plenty of tube charm in play. The soundstage was spacious and superbly solid, as if carved from stone. Image specificity was first class, allowing individual spatial outlines in an ensemble to shine through the mix. Tonal colors were vivid and midrange harmonic textures flowed sweetly with exceedingly low levels of grain. There was plenty of transient speed in evidence with sufficient lucidity to allow retrieval of low-level detail. When I think of an overly tubey, thick, and syrupy sound, I am reminded of the classic Dynaco PAS-2, the poster child for this sort of presentation. The DPMC is light years removed from all that. Imagine tube sound without excessive fat—with the DPMC you can have your sonic cake and eat it, too. However, the fly in the ointment was mc performance relative to that of the mm cartridges. On some albums, bright upper registers, for me a major sonic turnoff, ultimately resulted in listener fatigue.

The foregoing conventional imaging and tonal color descriptors hardly do the DPMC justice. It proved to be one of those rare components that involve and pull you into the music. Put another way, it was able to communicate the music’s pace and rhythmic drive to a degree that is exceptional at this price point, propelling musical lines forward with startling verve. Pace and rhythm are the perceptual parameters that standard high-fidelity specs don’t capture. The fact that perceptual attributes such as soundstage depth can’t be measured with test gear is glossed over by Henry Kloss’ famous quote: “If it measures good, but sounds bad, you measured the wrong thing.” There probably isn’t a way to conventionally engineer, i.e., by measurements alone, the sort of perceptual attributes audiophiles are after. Yet some designers measure their way to a final product without conducting any listening tests along the way. That definitely is not the Jadis way. My thesis is that fidelity to the real thing is best approached by voicing and selecting various components via listening tests. Harry Olson, a giant figure in American acoustical engineering, put it thusly: “In all things audio, the ear is the final arbiter.” That was true in his lifetime and is just as relevant today.

Finally, it was time to take the main phono front end for a spin, and into unchartered waters looking into a fixed 47k ohm loading. Although the Da Vinci mc is reasonably immune to cartridge loading effects, it complained on certain records with a bit of gratuitous brightness. I had much better luck running the DPMC directly into the Lamm Audio monoblocks. In exchange for a slight loss of bass definition the DPMC delivered plenty of tube virtues, and even managed to sound naturally balanced on some recordings. While the Pass Labs XP-25, my standing phonostage reference, offers better bass control and greater transient speed and soundstage transparency, the DPMC sounded much more seductive. Think enhanced spatial perspective, and fatter, richer, and more liquid textures. Putting the argument of accuracy aside for the moment, I can tell you that the Jadis was more pleasurable to listen to.

The Jadis DPMC’s tube signature is unmistakable. It romances the soul, and I for one could not resist its siren call. With a good mm cartridge in tow, the DPMC is musically compelling. It celebrates the music with unmistakable joie de vivre. Join the fun; you’ll be glad you did.

SPECS & PRICING

Gain: 66dB
Input impedance: 47k ohm
Output impedance: <1k ohm
Power consumption: 30W
Dimensions: 17.9** x 4.9** x 12.6**
Weight: 11 kg
Price: $6900

JADIS
5 Chemin du Pech
11800 Villeduber
France
jadis-electronics.com

BLUEBIRD MUSIC, LTD. (U.S. Distributor)
(416) 638-8207

Associated Equipment:
EnigmAcoustics Mythology M1 loudspeaker; Lamm Audio M1.2 Reference; Kuzma Reference turntable; Kuzma Stogi Reference 313 VTA tonearm; Clearaudio Da Vinci V2 MC phono cartridge; PrimaLuna Dialogue Premium line preamplifier; FMS Nexus-2, Wire World, and Kimber KCAG  interconnects; Acoustic Zen Hologram speaker cable; Sound Application power line conditioners 

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