Kloss began his custom of eponymous products by lending his last name's initial to KLH as a founder in 1957, along with Malcolm Low and J. Anton Hofmann (son of pianist Józef Hofmann) who had also been investors in AR. At Cambridge-based KLH, Kloss continued to build speakers such as the classic KLH Model Five and Six, and produced one of the first small FM radios with high selectivity, the Model Eight. Though KLH was sold to the Singer Corporation in 1967, Kloss remained at the firm for a short time to assist in the development of additional speakers and electronic music products, and the firm continued to attract design and engineering talent. Kloss created the first solid state record player, the KLH Model Eleven. In 1968, he collaborated with Ray Dolby of Dolby Laboratories to develop the B version of the Dolby noise reduction system to reduce tape hiss. This resulted in the KLH Model Forty reel-to-reel tape recorder, Dolby's first foray into the consumer product market. By 1968, Kloss had left KLH. KLH was eventually sold to Kyocera, and production was shifted overseas. By 1979, nearly all of the original design and engineering team had left the company.
Kloss founded Advent Corporation in 1967. The name came from the legal description the advent corporation ("advent" means approaching in Latin) used in the incorporation documents before the actual name is selected. The original goal had been to develop a projection television, but by 1968 he had quit KLH to build a remarkable dual driver speaker system with 10 inch (25 cm) woofer called simply The Advent Loudspeaker (later colloquially called the Large Advent after introduction of The Smaller Advent Loudspeaker). It rivaled the sound of the then top-line AR Model 3a (which used three drivers and a 12 inch (30 cm) woofer), but only cost about half as much. He then went to work on increasing the fidelity of cassette tapes, a format that had originally been meant to be used only for dictation. Kloss introduced the Advent 201 in 1971, incorporating Dolby B along with chromium dioxide tape and became one of the first to offer a high fidelity cassette deck. These units were manufactured for Advent by Nakamichi.
The Advent Video Beam 1000 was finally released in 1972, the first large screen projection television for home use. This led to founding Kloss Video Corporation in 1977. He invented the Novatron tube there, which increased the efficiency of projection TVs.
Eventually, long after Kloss’ departure, Advent ran into hard times and never emerged from a bankruptcy declared in March 1981. Kloss’ own Video Corporation passed on reacquiring the New Hampshire based brand, which was later merged into International Jensen.
Kloss continued to work on other projects until his death in 2002 of a subdural hematoma. His home was sold to new owners, with the basement reportedly still was full of Kloss' own personal electronics lab equipment, accumulated over a lifetime. The equipment was discarded as salvage.