1964 Vox Ac30/6 (Treble)

This is one collectible and fantastic sounding British made amp. The Vox AC30 is an iconic sounding piece of gear and this particular version is the “Treble” edition. Vox at this time released the AC30 in “Bass”, “Normal”, “Treble”, and the higher gain “Top Boost” editions - with each voiced respectively to accentuate certain frequencies. This was done through the use of different value coupling and peaking capacitors mostly in the front end of the preamp. These amps have the incredible phase shift vibrato and amplitude modulation tremolo circuits lifted directly from the Wurlitzer console organs of the era.

This one came in completely original condition - nothing had been worked on. All filter/bias/bypass caps were replaced with upgraded voltage and temperature rated MOD and F&T brand electrolytic’s (including both cap cans). Two plate load resistors were replaced with vintage spec new production 1/2 watt carbon comp type as the originals had drifted high in value. Many solder joints were re-flowed for reliability and bad connection issues. All pots were cleaned out and lubricated.

The original tubes did not all test good and almost all replaced. V1 = NOS Mullard ECC83, V2 = EHX 12AX7, V3-V6 = JJ EL84 Matched Quad, V7 = JJ 12AX7S, V8 = EHX 12AU7A V9 = SOVTEK 12AX7WA, V10 = NOS Mullard GZ34. These tubes were picked for best tone, and reliability - all being individually selected for specific circuit positions. The cathode bias was set to %90 Class AB Plate Dissipation with a B+ approximately 380VDC. All hardware was tightened and the amp was cleaned.

This amp came back in after being dropped, with a blown voice coil in one of the original Alnico 12” speakers. We decided to go with a new pair of Weber Alnico Blue Dog’s (Light Doping) at 8 Ohms each with a 30 Watt power rating to prevent future blow-out’s. This made the amp sound even better in my opinion.