(each containing four speakers) were modified for stacking, which has become the norm for years to follow. Entwistle and Townshend both continued expanding and experimenting with their rigs, until (at a time when most bands still used 50–100 W amplifiers with single cabinets) they were both using twin stacks, with each stack powered by new experimental prototype 200 W amplifiers, each connected to the guitar via a Y-splitter. This, in turn, also had a strong influence on the band's contemporaries at the time, with Cream, The Jimi Hendrix Experience and Led Zeppelin following suit. However, due to the cost of transport, The Who could not afford to take their full rigs with them for their earliest overseas tours, thus Cream and Hendrix were the first to be seen to use this setup on a wide scale, particularly in the United States. Ironically, although The Who pioneered and directly contributed to the development of the "classic" Marshall sound and setup with their equipment being built and tweaked to their personal specifications, they would only use Marshalls for a couple of years before moving on to using Hiwatt equipment. Cream, and particularly Hendrix, would be widely credited with the invention of Marshall Stacks. The search for volume was taken on its next logical step with the advent of "daisy chaining" two or more amplifiers together. As most amplifier channels have two inputs, the guitar signal being present on both sockets, the cunning musician hooked the spare input of one channel to an input on another amplifier. By 1969, Hendrix was daisy-chaining four stacks, incorporating both Marshall and Sound City amplifiers, as recommended to him by Townshend. This competition for greater volume and greater extremes was taken even further in the early 1970s by the band Blue Öyster Cult, which used an entire wall of full-stack Marshall amplifiers as their backdrop. (BÖC also referred to Marshalls in the songs "Cities on Flame with Rock and Roll" and "The Marshall Plan"). Artists such as Slayer and Yngwie Malmsteen also use walls of Marshalls; both Kerry King and Jeff Hanneman of Slayer would often be seen playing in front of a total of 24 cabinets. Malmsteen toured with 30 heads and 28 cabinets, and in 2011 said he would use 60 full stacks on his next tour. Many of those cabinets used by rock bands, however, are dummies, and many artists who do not even