I LOOK FORWARD TO READ ing Invention & Technology , but when I openec the most recent issue, I knew I’d be in trouble. I agree with guitarists that tube-sound distortion is what they’re after (“The Tube Is Dead. Long Live the Tube,” by Mark Wolverton, Fall 2002), but I wince when people say they prefer tube sound over solid state when it concerns the reproduction, not production, of music. In almost any music the dynamic range is so large that a signal may occasionally get clipped in an amplifier, but in a properly designed amplifier, transistor or tube, the signal gets into and out of clipping practically inaudibly. If the sound is terrible, it is the fault of the user. Get a larger amplifier or turr down the sound.
I get particularly annoyed when people begin to romanticize about the glow, warmth, ether, magic, and sc on of the vacuum tube. Thai is absolute hogwash. There is no scientific basis for the belief that one is inherently better than the other.
The trouble is that manufacturers test for the simple stuff—distortion, power, and frequency response—and certain manufacturers’ consortium guidelines tend to give everyone high marks. There’s a lot more going on. For one thing, a tube is a high-impedance device, and a transistor is a low-impedance device. When tubes are used, a transformer is usually needed to match them to the load. That’s because when the voltage to a loudspeaker stops, the loudspeaker should stop, but it doesn’t, because the speaker has mass, and so a voltage is generated back on the speaker wires, which is, in effect, amplitude distortion. Low output impedance (also known as high damping factor) causes the speaker to react to the amplified signal and not to its own inertia. Therefore, solid-state amplifiers tend to sound tighter, particularly in the bass region, where the speaker is more resonant and harder to control. This is also why “monster” cables help, because they continue the low impedance from the amplifier to the speaker.
If you want a tube-type sound, you can easily emulate it by hooking up thin wire between your transistoi amplifier and your speaker, thereby reducing the damping factor. If you like a boom-box, muddy jukebox sound, go for it. You’ll save a lot of time and money try- ing to locate a working vintage tube amplifier.
Wayne E. Chou
FOUNDER AND FORMER CEO
C/M LABORATORIES
RIDGEFIELD, CONN.
