| The AC-100 MK II head was designed to be simple and loud. The amp featured only three controls and offered a whopping 100 watts RMS.
Not many manufacturers had attempted a 100 watt tube guitar amp prior to 1964. Until the Vox AC-100, the Fender Showman amp, rated at about 80 watts RMS, was the king of the hill.
The AC-100 Mk II design was accomplished with only seven tubes. The power amp section had four EL-34 output tubes running in Class AB mode. An ECC82 tube was used as a phase inverter to supply the output stage. The preamp section used one half of an ECC82 tube as a gain stage and one ECC83 tube to drive the tone comtrols. The power supply was comprised of a diode bridge, two massive 100 uf filter capacitors and a choke.
Trimuph Electronics supplied Vox the chassis for this amp. Triumph used an output transformer that had very thin and fine windings, quite unlike the thick transformer coils used on the Fender Showman. This transformer gave great tone to the AC-100 MK II but it also made the amp easily susceptible to failure should it be accidentally operated without an appropriate speaker load connected to the amp. A red warning placard attached to the back of the amp reminds the owner to connect speakers to the amp before turning the amp on.
The 3/4" thick, thirteen ply "thick edge" AC-100 Mk II head enclosure was covered in Vox "basket weave" vinyl. It is likely that this model was only offered with black Vox diamond grill. It is also likely that all AC-100 Mk II amp heads had gray control panels. The amp also included eight one pin corners, a single "Vox" handle, and a small gold plated -V-O-X- logo.
When compared to the extremely brilliant Vox AC-30 Top Boost, the AC-100 MK II is somewhat deficient in treble. Vox addressed this issue in the AC-100 the same way they had a few months earlier with the AC-50. A pair of Goodmans MIdax horns were added to the speaker cabinet to accentuate high end response.
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