JMI Vox Ac30 30/6 Top Boost



Very Rare Amplifier
Excellent condition, no damage, no scratch

This is the most celebrated version of the legendary Jennings Musical Industries amplifier, with features based on a 1961/62 design.

The combo features the classic design using brown grillecloth, black tolex covering , leather strap-type handles and two 12” Alnico Blue speakers.

The amp’s chassis includes the traditional red JMI control panel, point-to-point wired circuitry, three channels and six inputs (Vib/Trem, Normal, Brilliant), with an option of the classic Top Boost add-on circuit.

Control layout: Vib/Trem Speed, Vib/Trem Volume, Normal Volume, Brilliant Volume, Cut (tone), Top Boost , Bass, Treble Valve configuration: ECC82 (x 1), ECC83 (x 5), EL84 (x 4), GZ34 (x 1) (
Wattage: 30W
Speaker Options: Blue Alnico
Variable mains voltage selector

Production – UK Made within the JMI Factory 

The Vox AC30/4 “Four Input” Combo Amplifier (1960 – 1961)
Tom Jennings, president and founder of JMI (the parent company of Vox) was keenly aware of the impact that celebrity endorsees would have on the sales of Vox amplifiers. Jennings scored a major victory in 1959 when the UK instrumental band the “Shadows” replaced their Selmer amplifiers with the first generation Vox AC-15. In addition to producing instrumental guitar hits such as “Apache” and “FBI,” the Shadows were also the backup band for the UK singing sensation Cliff Richards. The Shadows introduced many young British musicians, including the Beatles, to Vox amplifiers.

The AC30/4 featured a black and gold anodized control panel divided into five boxes. The box at the far left was labeled “Inputs.” The amp had four inputs. two each for the Vibrato and Normal channels. The input jacks for the Vibrato channel had white nuts, the Normal channel input jacks were black.
Moving to the right, the next control panel box enclosed the Vib/Trem controls. A three position “Speed” control adjusted the speed of the Vib/Trem. A second panel mounted rotary switch labeled “Switch” toggled between the tremolo and vibrato effects. An egg shaped foot switch turned off the Vib/Trem circuit.
The volume controls were in the control panel box labeled “Volume.”
Next came the “Tone” control section. The “Brilliant” rotary switch affected the treble response of the Nornal channel. The “Bass” control rolled off the treble response of both channels.
The power switch, power indicator lamp, fuse and a mains voltage selector were on the right side of the control panel.

Cabinet Design
The AC30/4 was the first AC-30 to incorporate the traditional “split front panel” design shown at left. However, the early AC30/4 amps delivered to the Shadows still had a “TV” front cabinet.

While the AC30/4 shown at left had a pair of Celestion G12 Alnico “Blue” speakers, some early AC30/4 amplifiers were fitted with an earlier version of the same speaker, shown at right. These were painted tan and did not include the pressed steel magnet cover found on later Celestion Alnico 12″ speakers.



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