horizontal deflection tetrode. Throughout the 1950s, as prices of capacitors decreased, designers steadily increased their values. The original Williamson amplifier used paper capacitors; by 1952 Kiebert uses electrolytics; the 1955 reference design by Keroes used at least bypass capacitors; the 1961 budget amplifier by Wright employed a total of . Designers of the commercial Bell2200 amplifier (1953) replaced direct coupling of the first two stages with capacitive coupling; the Stromberg-CarlsonAR-425 (also 1953) use a tetrode-mode output stage in an otherwise familiar Williamson topology. Both Bell and Stromberg-Carson modifications further worsened stability, and required additional frequency compensation. Designers of the BogenDB20 (1953) went even further, and combined global and local negative feedback loops with positive feedback in the output stage. In December 1951 Hafler and Keroes began promoting the ultralinear stage - a method of distributing load between anode and screen grid of a pentode or tetrode, invented by Alan Blumlein in the 1930s. An ultralinear stage delivered 50% to 100% more output power than the same stage in triode connection, at roughly the same distortion, and cost less than a pure pentode or tetrode stage (the latter required a separate screen grid supply, the ultralinear did not need it). The first Ultralinear Williamson, employing a pair of 6L6 in a Williamson-like topology, delivered ; their second model, built around more powerful 807 tetrodes, delivered . Very soon the American public acquired taste to high-power amplification, and the industry launched the "race for Watts". By 1955 Hafler and Keroes, now working separately, were offering 60-Watt models employing pairs of 6550 tetrodes or quartets of KT66s. Thus in less than a decade, step by step, the industry abandoned the principles set by Williamson, but continued to use his name as a convenient free trademark. In the 21st century it is even used for amplifiers without global negative feedback; the only thing they have in common with the true Williamson amplifier is the four-stage topology. Following the success of Hafler and Keroes, American manufacturers like Eico, The Fisher, Harman/Kardon and Marantz disposed with "obsolete" power triodes and switched to ultralinear designs. Mullard, Britain's largest valve manufacturer and provider of reference designs to the European industry, publicly supported the novelty. Williamson's former employer, General Electric Company, followed suit and published a reference "30-Watt Williamson" design built around a pair of ultralinear-connected KT88. The original Williamson amplifier lost the race, just like alternative designs by