The Vox Pacemaker was essentially the same amp as the Cambridge Reverb, but less the reverb circuit. In the two years between 1965 to 1967, Thomas Organ developed three different versions of the Pacemaker amplifier. They are detailed below.
Pacemaker V-2 - Introduced in 1965, the original Pacemaker was an all tube amp with circuitry inspired by the JMI Vox AC-15 amplifier. The five tube circuit featured two ECC83 preamp tubes, two EL84 output tubes, and one EZ81 rectifier tube.
There is a significant difference in the power amp circuitry of the V-2 Pacemaker and V-3 Cambridge Reverb. Both amps produce 17 watts RMS, but the Pacemaker uses just one half of a ECC83 preamp tube as a “Cathodyne” or “Split-Load” phase inverter to feed the EL-84 output tubes. The Cambridge Reverb uses a both triodes of an ECC83 in a "long tailed pair" phase inverter.
The single channel amp had three inputs and foot switchable tremolo.
Like the British AC-15, the 17 watt RMS tube output stage of the Pacemaker V-2 was cathode biased. The preamp used a slight variation of the "top boost" circuit from the AC-30.
Thomas Organ imported a 10" Celestion speaker from the UK for the earliest version of the Pacemaker V-2. These early models also had a one piece back with an oval shaped cutout behind the speaker. Later versions of the Pacemaker V-2 replaced the Celestion with a 10" "Gold Bulldog" speaker made by Oxford Speaker of Chicago IL. This later version of the V-2 also had a split, two piece back.
The control panel featured three instrument inputs plus volume, treble, bass, tremolo speed and tremolo depth. The lower control panel included a foot switch jack and an external speaker jacks. The power switch featured a standby function and dual pilot lamps indicated whether the amp is in "standby" or "operate" mode.
The cabinet of the Pacemaker V-2 was constructed of fir plywood and was covered in a basket weave pattern vinyl. A horizontal Vox logo, eight one pin corners and a single button foot switch to actuate the tremolo were included.
The 1965 US Vox price list indicated that the retail price for the Pacemaker V-2 and accessory single button foot switch was $129.90. Adjusting the 1965 retail price of the Pacemaker amp V-2 for inflation to today's value of the dollar, this amp would now cost $875.
Many thanks to Joseph Appel for allowing me to photograph his early V-2 Pacemaker amp for the Vox Showroom.
Pacemaker V1021 - Introduced in 1966, the Pacemaker V1021 featured all transistorized, or "solid state" circuitry.
The control panel functions of the Pacemaker V1021 were identical to the V-2 tube version of the amp. Unlike the V-2, the V1021 also featured MRB, or "Mid Resonant Boost." MRB was not switchable from the control panel. Rather, a two button foot pedal was included with the amp to remotely control tremolo and MRB.
The Pacemaker V1021 17 watt RMS power amp was powered by two germanium power transistors.
Vox dropped the Celestion 10" speaker previously used in the Pacemaker V-2. It was replaced with an American made Oxford 10" "Gold Bulldog" alnico speaker.
The cabinet of the Pacemaker V1021 was constructed of particle board and was covered in a levant grain vinyl. A horizontal Vox logo, eight one pin corners, and a US version of the JMI Vox strap handle with brass plated handle loops were featured.
The 1966 US Vox price list indicated that the retail price for the Pacemaker V1021 with the accessory two button foot switch, cover, and chrome stand was $149.90. Adjusting the 1966 retail price of the Pacemaker V1021 for inflation to today's value of the dollar this amp would now cost $980.00.
Pacemaker V1022 - The Pacemaker V1022 was introduced in 1967 and the was the final incarnation of this amp. Like the V1021, the V1022 was a "solid state" amp.
Two minor changes differentiate the V1021 and V1022 Pacemaker models. The V1022 had an "E Tuner" switch on the lower control panel and there was a slightly different germanium output transistor used in the V1022.
The 1966 US Vox price list indicated that the retail price for the Pacemaker V1022 with the accessory two button foot switch, cover, and chrome stand was $160.00. Adjusting the 1966 retail price of the Pacemaker V1022 for inflation to today's value of the dollar this amp would now cost $1016.00.
Many Thanks to Jeffrey Gish of the Britins for allowing me to photograph his V1022 Pacemaker amp for the Vox Showroom.