VOX MIDAS AMPLIFIER
Vox Sound Ltd - 1970-1973
The Vox Midas amplifier in the Vox Sound Ltd brochure of 1970, described on a previous page as being new to the range. Its price in the pricelist of 16th Aug. 1970 is £106.
In actual fact, the Midas - in two versions, one 50W, the other 100W - was made ready by "Vox Sound Equipment Limited" for the British Musical Instrument Trade Fair, 17th-21st August, 1969. So technically speaking it was not really all that new in mid 1970, when Vox Sound Limited came into being and advertised it.
Above, a detail from a shot of the Vox Sound Equipment Limited display at the British Musical Instrument Fair at the Russell Hotel, London, 17th-21st August, 1969. The Midas is at back on the right.
Gary Hurst's report on the Fair in Beat Instrumental, October 1969.
The styling of the amp followed the lead of the PA 50SS and PA 100SS, issued by Vox Sound Equipment Ltd in August 1968. Examples of these can be found on this page.
Its name was probably a dig at the unsuccessful flight recorder that brought down Royston Industries and Vox Sound Equipment Limited (the forerunner of VSL) along with it.
It is interesting to note that versions of the Midas were incorporated in two Gyrotone rotating speaker cabinets produced by Vox Sound Ltd - the Gyrotone 50 with a Midas 50 (possibly not issued as a separate unit); and the Gyrotone 100 a Midas 100, similar though not absolutely identical to the units on this page.
Despite the blurb in the advert, few Midases were given reverb. For a unit that has it, see this page. No. 1053 below certainly does not.
In terms of functionality, there were two channels, one for music the other for a microphone. Both had volume, treble and bass. Overall levels were controlled by a master volume. Outputs for two speaker cabinets and a Gyrotone unit were provided on the back panel. Speaker impedance was selectable between 4, 8 and 16ohms.
The design of the power section was borrowed from the PA100SS. Its main transistors are 2N3055s
The mains plug (lower left on the front of the amp) was a Belling Lee L1722, standard for the solid state line.
The chassis, which slides out from the front of the case when the bolts running through the feet on the underside are removed, is rack-mountable, being 19 inches wide, 3U in height.
The schematics floating around on the web for these amps are almost illegible unfortunately. When a good copy comes to light it will be included here.
For the Midas 100, the schematic sheet is OS/208; for the Midas 50, OS/209
Below, images of two surviving units - serial number 1053, and at the foot of the page serial number 1119. Relatively few Midases seem to survive - perhaps because their application was relatively limited. If anyone knows of any others, do let me know.
A Vox Midas currently in the UK - serial no. 1053
The red CCL capacitors in the bias string are dated June 1970. The sealed Erie pots have codes "230" and "270" - presumably 23rd and 27th week of 1970. A couple of power transistors were replaced at some point after 1976. The original 2N3055s and 2N3054s have the code "EZ" = May 1969.
Serial number 1119
Sold on ebay in late summer 2016. one can see the multi-pin output for the Gyrotone rotating speaker cabinet.