The Marshall ‘Stack' - taken from www.thewho.net

Though someone would've likely “invented” it sooner or later, John Entwistle and Pete Townshend are responsible for the development of the de rigueur rock guitar amplifier setup known as the “stack” and the 100-watt amplifier.

John's and Pete's desire (and escalation) to have the loudest gear was the impetus for Marshall to build the first 100-watt amplifiers. Jim Marshall, owner of J&T Marshall Musical Instruments, LTD, a music shop in Uxbridge Road, Hanwell, West London, and whose engineers, Ken Bran and Dudley Craven, had begun building amplifiers for sale in their shop in 1962, notably the infamous JTM45 45-watt head (soon upped to 50 watts, as the model 1987) and the JTM45 combo (later the model 1962; made popular as the “Bluesbreaker” by Eric Clapton). Pete and John, as well as many other musicians of the time, were frequent customers of Marshall, urging him in the “latest” direction of the burgeoning West London music scene. The JTM45 was modeled after the ‘ideal' sound of the Fender Bassman, a 50-watt amplifier; however, for John's and Pete's needs, that wasn't loud enough to “drown” out the audience (or play louder than the likes of Keith Moon ). Many amp manufacturers' collective fear was that 100 watts would be impossible because of component meltdown.

Ken Bran's first attempt in 1965 was a four 6V6 output valve configuration; the second used four 6L6 valves and the third had four KT66 output valves.

Pete and John bought the first four, at £160 each.

The stack derived from both a desire to project sound better and a desire to have an intimidating backline. In 1964, John first connected his Marshall JTM45 to, first one, then two side-by-side Celestion G12-loaded Marshall 4x12s. Pete followed this up by placing his Marshall 4x12 on a waist-high metal stand, thus generating considerable feedback to the guitar's pickups. Next, possibly due to the small stages at the time, as well as to create an imposing visual force, Pete stacked one cabinet atop another, driven by his '64 blonde Fender Bassman 50w head (gold sparkle grille, white round knobs), and thus the “stack” was born. The bottom cabinet was likely a dummy, even at this time.

In mid-1965, John and Pete would switch to Vox gear, Pete with two Vox AC-100 (later known as the “Super Beatle”) 100-watt amplifiers and cabinets (and John with two Vox T-60 amplifiers and cabinets; See Max The Mod 's great description ). Unsatisfied with the sound (and following their van being stolen on 2 September; after which they leased Vox gear until November, when they unceremoniously dumped it back at the hire company), however, they returned to Marshall for their continuing quest for volume and power. Pete urged Marshall to develop an actual “stack,” an 8x12 cabinet. Delivered in November 1965, the 8x12s would pair up with the 100w amplifiers to create an imposing backline. The 8x12s featured an angled top portion and a straight profile for the remaining six speakers. These cabinets actually had an open back to the top portion, closed on the bottom. For the most part, these cabinets had all the features of today's “stack,” but proved unwieldy with their weight and size. Marshall only made six of these 8x12s, four going to The Who and two to the Small Faces. In late 1965, production versions of this “stack” followed in the Marshall 1960A (angled-front top 4x12 cabinet) and 1960B (base; flat-front 4x12 cabinet), the instantly recognizable Marshall “stack” of today.

Through 1966-67, Both Pete and John varied their setups, either in traditional stack form, with the amp on top of the cabinets, two amps stacked high, one on top of the other, on top of cabinets, or as a precursor to their future rigs, with the amps on a stand or chair next to the speaker cabinets. Pete early on ran the guitar to a split “Y” cable to power both amplifiers. Later, he used “daisy chain” cabling, where the guitar lead went into the “High Treble” input of channel I amp and out of channel II into the second amp.

Pete and John used these preproduction 100-watt amplifiers and the 8x12s, as well as other Marshall amps, such as the production JTM100s and '67 1967 Marshall Major Lead (affectionately called the “Pig”) 200w amps, and 1982 and 1960 Marshall 4x12 cabinets, into 1967. In early 1967, John would transition to Sound City L100 amplifiers and cabinets, and soon after, in mid 1967, Pete would follow suit, using two Sound City L100 100-watt heads and four Sound City 4x12 cabinets (with the bottom two as dummies), a precursor to his most famous setup, two Hiwatt CP103 100-watt heads and four Hiwatt SE4123 4x12 cabinets (with the bottom two as dummies).

Specs of Marshall amps used by Pete from 1965–1967

JTM45 50 (prototype model 1987) amplifier head (in late 1964/early 1965)

• First 50-watt amp, bumped from 45-watt JTM45.
• ECC83 (12AX7) and KT66 or EL34 valves
• Used primarily by John Entwistle (Pete preferred a Fender Bassman top or Fender Pro top through the Celestion G12-loaded Marshall 4x12 cabinets.)

JTM45 100 (early model 1959 JTM100 Super Lead) amplifier head (in November 1965)

• First 100-watt amplifiers; Pete and John bought the first four made, likely pre-production models.
• Two 50w transformers,
• JTM45 panel
• Four ECC83 (12AX7) and four KT66 valves
• Block ‘Marshall' logo
• Solid State rectifier
• Four inputs (two high, two normal), two channels
• Six controls: Presence, Bass, Middle, Treble, High Treble/Loudness 1 (Bright channel), Normal/Loudness 2 (normal channel)

JTM45 100 Tremolo (1959T JTM100 Tremolo Super Lead) amplifier head (in November 1965)

• Same as JTM45 100 (1959 JTM100 Super Lead), but with Tremolo
• Eight controls: Speed, Intensity, Presence, Bass, Middle, Treble, Loudness 1 (Bright channel), Loudness 2 (normal channel)
• On early models, small “The Who” shield badges on top left corner of amp head, eventually lost.

1959 JTM100 Super Lead amplifier head (in 1966)

• JTM50 panel
• Script ‘Marshall' logo with gold coloured plating:
• Four ECC83 (12AX7) and four EL34 valves
• Single 100w transformer
• Four inputs (two high, two normal), two channels
• Six controls: Presence, Bass, Middle, Treble, Loudness 1 (Bright channel), Loudness 2 (normal channel)

1967 Marshall Major Lead (The “Pig”), '67

• Two ECC83, one ECC82 and four KT88 valves
• Three controls: Volume, Treble, Bass
• 200 watts
• Four inputs

Marshall 4x12 speaker cabinets

• No model number on these early cabinets
• Four Celestion G12 12 ? speakers
• Used from late 1964 through mid 1965.
• John bought the second, fourth, seventh and eighth (or 2nd, 5th, 8th, 9th) produced by Marshall; Pete bought the ones in between (the first was bought by the Flinstones' bassist).

8x12 Marshall speaker cabinets

• Only six built (two to Pete, two to John, and two to the Small Faces)
• Top “cab” is open backed, bottom is closed backed.
• Eight 20w 12 ? Celestion speakers.
• Used from November 1965 through late 1966.
• Large curved handles on either side.
• Small “The Who” shield badges on cabinet crossbar, which were eventually lost.

1960A (angled front) and 1960B (straight front) speaker cabinets

• 75 watt, 16 Ohms
• Four heavy duty 12 ? Celestion speakers
• Early 1960B straight-front cabinet was considerably taller than the 1960A.

1982A (angled front) and 1982B (straight front) speaker cabinets

• 100 watt, 16 Ohms
• Four high power 12 ? Celestion speakers
• Early 1982B straight-front cabinet was considerably taller than the 1960A.