Solid State Power Amp Reviews

Nothing like scarcity to create demand, right? Well, there's been a scarcity of Nuvistors out there for decades, and hardly any demand. Do you know about the Nuvistor, aka the 6CW4? It was a tiny triode tube smaller than your average phono cartridge. Enclosing its vacuum in metal rather than glass, the Nuvistor was designed as a long-lived, highly linear device with low heat, low microphony, and low noise---all of which it needed to have any hope of competing in the brave new solid-state world emerging when RCA introduced it in the 1960s.

Rumor had it that if the MF2500 amplifier had gotten any better in development, Conrad-Johnson would have had to include it in their "Premier" series. However, C-J's intention was to hold to the lower price of their established MF series, and so they have. Rated at 240Wpc and retailing for $3495, the '2500 is the core model of Conrad-Johnson's current range of "MF" power amplifiers. Its companion MF2250 offers 120Wpc, while the MF5600 delivers 120Wx5 for multichannel home-theater applications.

Recently I found myself on the phone with Linn's chief design engineer, Bill Miller, talking about switch-mode power supplies. Affable Mr. Miller was ensconced in Linn HQ in Glasgow, Scotland. After a bit I inquired if Head Man Ivor Tiefenbrun was about the manse, and was quickly handed over. "You're such a cheeky guy. Why'd you call it the Klimax?"

I've heard my share of Krells, Levinsons, Rowlands, and the like in other people's systems—expensive solid-state amplifiers are not my usual beat. With the exception of an inexpensive Adcom a few years back, for more than a decade I've owned and reviewed only tube amps. In fact, until the $7500 Ayre Acoustics V-1 showed up, I'd not had one in my system. Similarly, I'd had only tube preamps until I reviewed the Ayre K-3, which so impressed me that I asked to hear the more">http://www.stereophile.com//amplificationreviews/609/">more expensive K-1—and ended up buying it.

As a reviewer who has focused on seeking out high-quality audiophile gear for cost-constrained readers, I'm embarrassed to say that the flagship RB-991 stereo amplifier is the first Rotel product I've had in my house. (To be fair to myself, this 38-year-old family-owned company did not develop a large US market presence until this last decade.)

Pass Laboratories' X amplifier series represents the efforts of designer Nelson Pass to prove that simple linear amplifier topologies can be scaled to provide high-quality audio performance at very high power levels. The handsome X1000 monoblock under scrutiny here, the largest and most powerful amp in the Pass stable, makes 1000W into 8 ohms and a mighty 2000W into 4 ohms. The amplifier has no global negative feedback, and only two gain stages: the front-end provides all the voltage gain and feeds a high-current follower stage.

What fascinates me about the High End are the electric personalities behind it. Manufacturers typically invest so much of themselves in the products they make. It's a divine madness—they do it because they have to. They're driven to it with a real sense of mission and excellence. But God forbid you criticize any of their offspring...ooo-la-la!