Robert W. (Bob) Carver is an American designer of audio equipment based in the Pacific Northwest.
Educated as a physicist and engineer, he found an interest in audio equipment at a young age. He applied his talent to produce numerous innovative high fidelity designs since the 1970s. He is known for designing the Phase Linear 700, at 350 W per channel the most powerful consumer audio amplifier available in 1972. He went on to found the Carver Corporation in 1979, Sunfire in 1994, and the Bob Carver LLC in 2011 which was sold to Jade Design in June, 2013.
However, in December 2013, Bob Carver and Jade Design parted ways.
Amplifier modeling
Carver caused a stir in the industry in the mid-1980s when he challenged two high-end audio magazines to give him any audio amplifier at any price, and he'd duplicate its sound in one of his lower cost (and usually much more powerful) designs. Two magazines accepted the challenge.
First, The Audio Critic chose a Mark Levinson ML-2 which Bob acoustically copied (transfer function duplication) and sold as his M1.5t amplifier (the “t” stood for transfer function modified).
In 1985, Stereophile magazine challenged Bob to copy a Conrad-Johnson Premier Four (the make and model was not named then, but revealed later) amplifier at their offices in New Mexico within 48 hours. The Conrad Johnson amplifiers were one of the most highly regarded amplifiers of the day, costing in excess of $6,000 a pair.
In both cases, the challenging amplifier could only be treated as a “black box” and could not even have its lid removed. Nevertheless, Carver, used null difference testing, (null difference testing consists of driving two different amplifiers with identical signal sources and exact levels, but out of phase by exactly 180 degrees. If the amplifiers were 100% identical, no sound would be heard. If sound was heard, the audio amps had different properties). Bob Carver used "distortion pots" to introduce amplifier characteristics, fine-tuned to null-out any sound differences. His modified amplifier sound was so similar, Stereophile Magazine editors could not tell the difference between his amplifier and one costing more than $6,000. This amplifier was marketed as the M1.0t for about $400.00. Carver successfully copied the sound of the target amplifier and won the challenge. The Stereophile employees failed to tell the difference in their own listening room.