Thoroughly minimalist in design, the Beatles version of the AC-50 "Small Box" head had one channel with two input jacks, volume, bass and treble controls, a pilot lamp, two speaker output jacks and a power switch. A voltage selector on the top panel allowed the amp to accomodate different power standards throughout the world.

The compact AC50 "Small Box" cabinet is primarily made of 3/8" thick baltic birch plywood. The top is 3/4" baltic birch plywood. The front edge of the top of the cabinet is milled down from 3/4" to 3/8" to match the thickness of the sides and bottoms.

Dick Denney told me that originally Vox wished to make their amps as small as possible. He told me that in the early years, Vox felt that "an amp head should be no larger than the size of a lunch pail." The AC-50 "Small Box" head seems to meet that requirement.

The amp head shown in the picture above is one generation removed from the "Beatle" version of this amp. This next generation amp still has only one channel and a tube rectifier, but it has four, rather than two, input jacks. These jacks are arranged in the shape of a diamond.

The electronic components in the AC-50 "Small Box" were hand wired on tag strips. The preamp used the "Top Boost" circuit from the AC-30. The output amp had two EL-34 power tubes in a Class A cathode biased circuit offering a 50 watt RMS power rating. The power supply featured a GZ-34 rectifier tube.

The power cord connector used on the amp was a male four pin XLR. This connector would never be acceptable in today's world, but Vox used it on a number of amp models in the 1960's.

The lack of treble response in the AC-50 "Small Box" amp head was a dissapointment to Vox. The large bottle EL-34 power tubes in the AC-50 were bassier than the small bottle EL-84 tubes in the AC-30. The increased bass response from the EL-34 tubes effectively masked the amount of treble coming from the amp. Vox found a solution to this problem by adding a Goodmans Midax horn to the speaker cabinet to boost the higher frequencies.