Tube Power Amp Reviews

It began when I reviewed the MartinLogan Montis loudspeaker (September 2012). The amplifiers I had to drive the pair of them were the PrimaLuna ProLogue Premier integrated ($2999), the Audiopax Mk.II (no longer available; the Mk.III costs $22,000), and the Simaudio Moon Evolution W-7 ($9000). The first two are tubed, with power in the 30–40Wpc range; the solid-state Simaudio puts out 150Wpc. The Audiopax, which sounds great with my Avantgarde Uno Nanos, turned out to be not such a good match for the Montises: weak in dynamics, and too soft sounding. The PrimaLuna and the Simaudio were better overall, each with its strengths and weaknesses, though neither was ideal. I really liked the ProLogue Premier's tonal characteristics, and wondered what a higher-powered tube amp would sound like with the MartinLogans.

This should have been a recipe for disaster.

It's no secret. David Manley has not been big on single-ended amplifiers. Not enough muscle. You're better off with push-pull. Still, with a growing market for single-ended stuff, I'm sure Manley saw a need to do something. Of all tube designers, Manley has always been among the most prolific.

I've never written a love story before, but then, there's always a first time. This romance concerns the stunningly anthropomorhic Jadis Eurythmie II (mostly) horn speakers and the petite, jewel-like and vivacious Jadis SE300B amps—a 10W single-ended triode design with paralleled output tubes.

Kathleen and I, having flung ourselves into single-ended's embrace, have become, to some fashion, quite experienced. I've described the purity of presentation available with the Wavelength Audio Cardinal XS monoblocks when coupled with the Swiss-made Reference 3A Royal Master Controls in these pages (January '96). Using the Eurythmie speakers, which supplanted the 3As in our system, we've listened to Gordon Rankin's Wavelength Cardinal XS monos, the Kondo-san Audio Note Kasai parallel 300B stereo amplifier (next SE review to come), the ebullient and eager-to-please Cary 301SE 300B stereo unit, and the Jadis single-ended triodes, as well as our reference Jadis JA200s (yes, Jadis also does push-pull).

Owning a powerful tube amplifier is like owning a classic automobile. Great pleasure may be had, but ownership involves a little more care and maintenance than usual.

Jadis, an audiophile company specializing in all-tube amplifiers and operating out of a small French town, has enjoyed a good reputation for some years, even if some of its models have suffered from the reliability problems that occasionally afflict the largest tube amps. Another problem area is that of power consumption and heat output. In common with class-A amplifiers and high-bias A/B types, including solid-state models, larger tube amps give off substantial heat. The Defy-7's 240W idling consumption may or may not be welcome, according to your location and the season.

It's always good to have a reference. No matter the endeavor, references help guide us and set standards for all we do. For many hours of every day, I'm lucky to enjoy the reference of live, unamplified music. Right now, I average over 20 hours a week of rehearsals and performances of various ensembles, and four to five hours of listening to recorded music on my hi-fi. Clearly, for me, my musical reference is not the sound of my audio system, but the sound of live music created in various venues and acoustics.

One drizzly, gray morning I found myself with an unexpected hole in my schedule and an unusual hankering for doughnuts. Since my move to Portland, Oregon, last August, people from around the country have told me that I just had to try the over-the-top creations over at Voodoo Doughnuts. So I donned my raincoat and walked through downtown Portland for one of Voodoo's fried, raised, and glazed treats. Once inside Voodoo's tiny storefront, I chose two confections: a maple-bacon bar (yep, they put a whole strip of bacon on top of a doughnut), and an Old Dirty Bastard doughnut with chocolate frosting, Oreos, and a peanut-butter topping. They were delicious, and way more doughnut than one man should eat.

For anyone who's been around the audiophile block a few times, Conrad-Johnson Design is a brand that needs no introduction. My first acquaintance with Conrad-Johnson was before I began writing for Stereophile (more than two decades ago—time sure flies fast when you're having fun!). I was in the market for a new preamp, having become convinced that my Dayton Wright SPS Mk.II was the weak link in my system, and had narrowed my choices to two similarly priced products: a solid-state model made by PS Audio (I'm not sure of the model number), and the tubed Conrad-Johnson PV-2ar. They were carried by different dealers, who allowed me to take their preamps home over the same weekend for a direct comparison. I was impressed by both preamps, and was sure that either would represent an improvement over the Dayton Wright, but in the end decided to go for the PV-2ar. I later traded it in on a dealer's demo unit of another Conrad-Johnson preamp, the PV-5. And, as it turned out, one of my first reviews for Stereophile was of Conrad-Johnson's PV-11 preamp.