The Vox Super Foundation Bass Amp - 1967 - 1972

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British Line

Super Foundation Bass Head
JMI Vox introduced three new solid state bass heads in 1967, the 30 watt RMS Dynamic Bass, the 50 watt RMS Foundation Bass and the 100 watt RMS Super Foundation Bass. All three shared the same two channel solid state modular preamp section and Thomas Organ inspired control panels. The Dynamic Bass utilized the 30 watt modular solid state power amp section from its guitar amp counterpart, the Conqureror. The Foundation Bass shared the 50 watt power amplifier section with the Defiant. The Super Foundation Bass and Supreme guitar amps were powered by the same 100 watt solid state power amplifier module.

A complete Super Foundation Bass amp was nearly as tall as a Supreme or AC-100. At the time it was introduced, it was the largest and most powerful bass amp produced by Vox. To celebrate its size and power, Vox nicknamed the Super Foundation Bass the "Big Daddy" in their 1967, 1968 and 1969 product catalogs.

The head cabinet for JMI and VSEL (1967-1970) Super Foundation Bass amps featured black Vox diamond grill panels on the both front and rear faces. The amps also included two horizontal "Thomas" style Vox logos, two-pin corners and a strap handle with a Vox logo. The cabinet was covered in traditional Vox basket weave vinyl with gold string accents. The earliest of these amps would have a JMI serial number plate on the rear panel. The preamp circuit was detailed on JMI Vox schematic OS/137, the power amp circuit on OS/135. These schematics are available for purchase at North Coast Music.

A second version of the Super Foundation Bass head was produced during the Corinthian and Stolec Vox periods (1970 - 1972). The front panel featured black Vox diamond grill cloth and a horizontal Vox logo. The rear panel was covered in vinyl. Eight two-pin corners and a Vox logo handle remained. Silver string replaced the gold string accents used on earlier models (see photo at left). A crude silk screened serial plate was screwed to the back panel. These later Super Foundation Bass heads utilized a revised fuzz and MRB circuit, detailed on VSL schematic OS/185.

The upper control panel of the Super Foundation Bass "Normal" channel included two input jacks, a Mid Boost switch plus volume, treble and bass controls. The lower control panel included a distortion or "fuzz" control and a three position rotary switch to select one of three mid range boost frequencies (450hz, 600hz and 750hz).

The distortion circuit included three germanium transistors. The fuzz was actuated by an external single button egg shaped foot switch.

The "Bass" channel of the Super Foundation Bass included two input jacks, a volume control and the Thomas Organ/Vox inspired "Tone X" control. There were no additional effects in the Bass channel.

Tone-X was a single tone control that replaced the normal bass and treble controls. Tone-X was a sweepable parametric EQ control that offered about a 6 db boost from approximately 50 hz (control counter clockwise) to 300 hz (control clockwise). While uniquely designed, most bass guitarists opted for the greater tonal variation offered by the traditional tone controls of the Normal channel.

Super Foundation Bass Speaker Enclosure
At 44" tall and 24" wide, it would seem logical that the "Big Daddy" Super Foundation Bass cabinet would have more than one 18" speaker. This was not the case initially.

Like the Foundation Bass, the first version of the Super Foundation Bass enclosure was equipped with just one 100 watt 18" speaker. Vox simply increased the height of the standard Foundation cabinet by 17" to create the Super Foundation Bass enclosure. The 1967 Vox catalog describes the Super Foundation Bass as having a "giant frequency tuned cabinet with an 18" speaker." This 1 x 18" Super Foundation cabinet was offered from 1967 through 1969.

A dual 18" version of the Super Foundation Bass enclosure was introduced in the "green" 1970 Vox catalog and continued in production through 1972.

Super Foundation Bass "Roll-Away" Stand
Vox developed a two-piece "roll-away" stand for their solid state Dynamic Bass, Foundation Bass and Super Foundation Bass amplifiers. The stand was included in the price of the amplifier except for the 1970 model year when it was an extra cost option.

The lower portion of the roll-away stand was a chrome plated tubular subframe that bolted to the bottom of the speaker cabinet. Two 4" casters were mounted to the rear of the subframe. Two vertical tubes extended to the floor from the front of the stand, serving as front feet and leveling the enclosure to the casters.

The upper portion of the roll-away stand had a chrome plated tubular frame that bolted to the front top edge and rear of the speaker cabinet (see photo at left). The amplifier head was secured to this frame with two wingbolts. When the head was removed for transport, the upper roll-away frame became a hand hold, allowing the cabinet to be tilted back on to the casters and rolled like a dolly.


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Photos and editorial content courtesy Gary Hahlbeck, North Coast Music

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