Vox V806 Treble Booster
1966 - 1967

The Vox V806 Treble Booster was produced by the North American distributor of Vox, Thomas Organ of Sepulveda CA. The V806 Treble Booster was essentially a knockoff of the #149 Vox Treble Booster produced by Jennings (JMI) in the UK.

After securing the North American manufacturing rights for Vox in the summer of 1965, Thomas ceased the importation of UK Vox products for distribution in the US. Going forward, virtually all Vox products destined for the North American marketplace would be produced at Thomas facilities in either Sepulveda CA or Chicago IL. The V806 Treble Booster was shown on this web page was built in Sepulveda CA and had a US list price of $24.90 in 1966.

The V806 featured a chrome plated steel case measuring 4⅝" x 1¼" x ¾." One of the narrow sides of the case included a ¼" instrument input jack and on/off switch. A ¼" output plug extended from one end of the booster. This plug inserted into an input jack on a guitar amplifier. A standard nine volt battery supplied power to the V806.

While similar in appearance to the JMI Vox Treble Booster, Thomas Organ implemented two modifications to the V806 circuit. The JMI Vox Treble Booster utilized a three pole switch which facilitated true signal bypass when the booster was turned off. To reduce costs, Thomas Organ replaced the three pole switch with a dual pole model, eliminating the true signal bypass feature.

Thomas Organ also modified the JMI Treble Booster circuit to reduce gain. Thomas Organ lead engineer Stan Cutler explained the reason for this change in a letter written to Jennings president Tom Jennings:

"It was found that the [US Vox prototype] treble booster, then used with a high output guitar, caused distortion to be heard in the amplifier to which it was connected. Mr [Dick] Denney indicated that the same condition had recently been found in the Jennings treble booster. We determined that that the distortion was not caused by the booster itself, but was due to an overload of the input stage of the guitar amplifier. A change was made which split output transistor collector load into two parts [accomplished by resistors R3 and R4], thus dividing down the output approximately 7 db. Care was taken to leave sufficient gain so that the psychological feel of increased output occurred when the booster was switched on. The final modified unit was considered acceptable and equivalent to the Jennings unit except for reduced input/output gain.1"

The original Vox V806 schematic and parts list is provided below for those interested in building their own Treble Booster circuit.

Parts List - V806 Vox Treble Booster
R1 - 100k ohm, ½ watt
R2 - 22k ohm, ½ watt
R3 - 2.2k ohm, ½ watt
R4 - 2.7 ohm, ½ watt
R5 - 1k ohm, ½ watt
C1 - .0022 mica cap
C2 - 10 uf 15 volt electrolytic
C3 - .1 uf disc cap
Q1 - Green/Yellow Transistor
see below

North Coast Music offers the Green/Yellow Transistor for the V806 Vox Treble Booster

"Green-Yellow" Vox NPN transistor

1. - "The Vox Story," The Bold Strummer Ltd, 1993, David Petersen and Dick Denney, page 145


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