THE VOX V100

Advert from the Melody Maker, April 10th 1971

The V100 - Vox Sound Limited's move to introduce a 100W valve "concert" amp, perhaps too late in an already crowded marketplace. The recommended cab or cabs will presumably have been a Supreme 4x12" (midax horns had been dispensed with by 1971), a multi-link 4x12", or a 2x15" + 2x12", though nothing is said in the brochures and adverts.

Had a "name" artist or group taken a V100 or two up, VSL might have capitalised. As it turned out, probably fewer than two hundred were produced - a pity, as the amp is capable of producing a good sound.

In Germany in 1971, the V100 sold for 1585DM, the equivalent of around £140 at the time - a considerable amount:

"Vox Sound Limited" pricelist printed for the German market, 1971.

"Vox Sound Limited" pricelist 1972. The amplifier is described as being an all-purpose valve model - £65. "100V" should of course be "V100".

Below, Rainer Baumann of "Frumpy" with a Vox V100 amplifier on two red vinyl Marshall 4x12s, Beatclub, 1971:

Screen-grab from the YT clip below.

As can be seen from the flyer at the top of this page and the images of amps below, the box was effectively a standard solid state amp box slightly reworked.

The power section of these amps was based in part on the last iteration of the Vox AC100 - zener diodes to provide the bias voltage; doubled-up filter capacitors to increase reliability; and still the brimistor.

Thanks to Asle, a circuit diagram (schematic) of the "Vox Sound Limited" Vox V100, based on serial number 1063, and adjusted from OS/167, the sheet for the final version of the AC100. The power sections of the two amps are more or less identical. The preamp of the V100 is simpler, however - principally: no V3; the cathode bypass cap of the first half of V1 omitted; and the grids of V2 done differently.

V100 schematic, based on serial no. 1063, the drawing adjusted from OS/167 (below)

For reference, OS/167, the last schematic of the AC100, drawn in VSEL days (4th December 1969), which shows the design was very much alive even if the AC100 itself was out of production.

Some notes on the preamp of the V100, thanks also to Asle. Where the the AC100 has a "paraphase" phase inverter, the V100 has a "long-tailed pair" (V2). The 47k plate load resistor on V1a is unusual - most 12AX7/ECC83 stages use 100k or 220k. "Another peculiarity is the coupling cap between V1a and the volume control, at 3300pF. The value is right between the Normal (0.022uF) and Brilliant (500pF) channel coupling caps in the AC50. 3300 pF into 500k volume pot makes a high-pass filter at around 100 Hz. Very useful for guitar, not sure how it will sound with bass guitar".