Bob Carver - Product Naming

Product Naming

Carver has used some names which have clearly defined technical meanings:

• "Magnetic field coil power amplifier" -- audio amplifiers of the vacuum-tube era used transformers, incorporating coils of wire, to convert the high-voltage, low-current output of the output tubes to a low-voltage, high-current output suitable for loudspeakers. Output transformers are no longer necessary with amplifiers, including Carver's, that use transistors. Carver's US Patent 4,218,660 (see below) describes a power supply whose input switches on and off at an ultrasonic rate to adapt to the varying power demand of the amplifier. The innovation is in the power supply, not the amplification circuitry, and in the use of switching, not in the use of a coil or coils.
• The "auto-correlator" is a multi-band, single-ended dynamic noise filter, as described in US patent 3,989,897 (see below). The Phase Linear 1000, and the Model 4000 preamplifier, which incorporates the same circuitry, have noise reduction in four frequency bands, one in the bass intended to suppress turntable rumble and three in the treble intended to suppress tape hiss and such. The noise filters are controlled by signals derived from bandpass filters, not from a correlation process. Correlation is the comparison of two or more signals, while auto-correlation is the comparison of a signal with delayed versions of itself to determine the degree of similarity at different delay times -- useful, for example, to determine the amount of delay that produced an echo.
• "Sonic holography", as described in US Patent 4,218,585 (see below), is the enhancement of stereo imaging by introducing a delayed and equalized signal from the right channel at the left loudspeaker to cancel the signal from the right loudspeaker at the listener's left ear (and vice versa).
• The "asymmetrical charge-coupled detector" is not the FM detector circuit of Carver's tuners, but rather, as described in US patent 4,457,012 (see below), it is single-ended dynamic noise-reduction processing applied to the noisy left-minus-right component of a weak FM-stereo signal, along with artificial ambience generation to compensate for loss of ambience resulting from the noise reduction.