The Vox Gyrotone III rotary speaker cabinet (1967-1973)
Two speeds (slow and fast). One rotating 12" speaker, two static: 65-100W handling
Detail from a JMI brochure for Italy, early 1968. "The Vox Girotone in three versions. It's the Leslie of 1968". The Gyrotone III is centre picture, sloping lower and upper sections.
Detail from the JMI catalogue of Spring 1967. No illustration of the Gyrotone III, but a description.
Click to enlarge. April 1967 pricelist. Standard production models.
JMI promotional material indicates that Gyrotones III and IV were brought into being in the months after Gyrotones I and II had been devised. On the Gyrotone I, see this page. Details of the Gyrotone II can be found here.
The range in its settled form is listed in April 1967 (see above). The four models remained in production as a group until 1968. When "Vox Sound Equipment Limited" took over the Vox catalogue in late summer 1968, Gyrotones I and IV were deleted. Gyrotones II and III, however, survived through to 1973. By late 1971 both could be had with built-in Midas solid state amplifiers - the Gyrotone 50 being the integrated version of the Gyrotone II, and the Gyrotone 100 being the integrated version of the Gyrotone III.
An old shot of two Gyrotone IIIs and a Riviera organ at the Royston Industries headquarters in Mayfair, published in "Beat Instrumental" magazine, January 1969.
The principal use envisaged for the range was with organs - the Gyrotone III for larger halls, clubs, and the studio. Its effect was described as "Chorale". The tendency of guitarists to experiment with rotating speaker cabinets increased as the late 1960s wore on.
In terms of conception, the Gyrotone III is close to the Leslie 122 and 147 of the early 1960s. The Leslie cabinet marketed by Selmer in 1967 and 1969, in spite of its size, was slightly different to JMI's Gyrotones, having a built-in amplifier at base.
Detail from a VSEL brochure produced for the German market in 1969. Goodmans speakers are now standard.
Detail from the VSEL pricelist for the UK, February 1969. £150 was a substantial amount.
In 1969, "Vox Sound Equipment Limited" (1968-1969) devised a simplified cabinet with a flat single-piece front. Roller wheels were built into the bottom and plastic handles fitted in the back panel.
Detail from the "Vox Sound Limited" catalogue of late summer 1970. The Gyrotone III now with a single-piece front.
A detail from the pricelist that accompanied the catalogue above. Note that covers are extra.
It is likely that cabinets were made initially by Heslop and Co., based in Rayleigh, Essex, and along with JMI, a member of the Royston Group of Companies; and later by Henry Glass and Company, which was based in Hainault, Essex.
Key aspects of the Gyrotone III
JMI cabinets have split fronts with sloping upper and lower sections, both covered with cloth. Cabinet sides at top have inset lattices covered with grille cloth. Back panels are normally solid. Just under half-way down on the sides there are carrying handles.
Inside the cabinet, a slider board, the rotating fan and motor on top, a 12" Celestion T1297 speaker fixed to its underside in a wooden compartment. Two "static" Celestion T1297s in the front of the cabinet facing forwards, both with a port to depressurize the enclosure. The two Celestions were later superceded by Goodmans speakers. These were superceded in turn by a single 18" driver.
Low down on the side: the mains socket; fuse; jack socket for the input signal from the amplifier or organ selected to drive the cabinet; and footswitch connection. A multi-pin socket was later introduced for a connection to the Vox Midas Gyrotone amplifier.
A two-button footswitch was provided - one switch to turn the rotating speaker on or off, the other to toggle between fast and slow rotation.
Surviving Gyrotone III units
JMI serial number unknown
A rare surviving JMI Gyrotone III. Original speakers in place and what looks to be the original rotor mechanism.
Vox Sound Limited (1970-1973)
VSL serial number unknown
"Vox Sound Equipment Limited" speaker labels on the 12" Goodmans. The compartment fof the Gyrotone driver is constructed from chipboard.
VSL serial no. 069
A single 18" Goodmans driver with "Vox Sound Equipment Limited" label. The 12" Gyrotone driver is in the wooden compartment under the shelf.
VSL serial number 088
The multi-pin socket on the input panel is for the connection to a Vox Midas amplifier.
VSL Gyrotone 100
Two fixed Goodmans 12" drivers. The Goodmans under-shelf speaker has been removed. The Midas amplifier has also been removed (from the bottom of the cabinet). Note the cut out in the lower edge of the back panel. A page on the Gyrotone 100 will be available soon.