Jonathan Scull

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 <I>very</I> 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.

<B>Jonathan Scull: </B>Gordon, please tell us what you see as the basic difference between single-ended and push-pull.

We have to talk. Are you sitting comfortably? Is the reading light okay? Have a little something to drink at hand? (Audio is <I>thirsty</I> business.) The audio world is abuzz over the reintroduction of the single-ended triode amplifier. This is the first of three reviews of such amplifiers I'll be bringing you, along with two speaker systems with which to play them.

According to Cary Audio designer <A HREF="http://www.stereophile.com/interviews/399">Dennis Had</A> in this amplifier's documentation, "Countless hours were spent designing and voicing the CAD-280SA V12 stereo amplifier...It delivers high performance in a combination of class-A single-ended triode and true balanced push-pull technology."

With whom are you most intimate? Your wife? Husband? Your modern-times Significant Other? Your pet? Or, like a lot of audiophiles, is it your audio system? Do you nitpick and tweak it as if it <I>were</I> your pet?

Sometimes tweaks take on a life of their own. Take the one of using Armor All to keep speaker surrounds from drying out, which you can read all about in the November 2001 "Fine Tunes No.41" I recently got another e-mail on the subject from Dan Mazza at Arizona Hi-Fi, who agrees with Mark Gdovin's objections to using Armor All. (Read Mark's comments on the entire issue in the readers' letters linked to "Fine Tunes No.41.").)

As we all know, it's the sound that counts. However, good looks enhance pride of ownership, and Theta Digital's class-AB, 400W Citadel is as handsome a monoblock as these jaded eyes have laid eyes on.