Vox Ac30 Service Manual Fix Jun 2026

This is where most owners mess up. The manual states that the AC30 runs its EL84s —typically dissipating 11-13 watts per tube (well above the 12-watt max rating). This is by design. However, the manual also warns:

Visual maps of the electronic components, including tube stages (Preamp: 3 x 12AX7; Power: 4 x EL84). Parts Lists: vox ac30 service manual

| Component | Failure Mode | Recommended Replacement | | :--- | :--- | :--- | | | Arcing carbon tracks (TBX) | Ceramic, Belton or Amphenol. | | Cathode resistor | Overheating, open circuit | Wirewound 25W, mounted 1" above board. | | V1-V3 plate resistors (100kΩ) | Noise, drift | 1W metal film (CC2) or carbon comp (TBX for vintage tone). | | Treble bleed cap (TBX channel) | Leaky, causes scratchy vol pot | 100pF silver mica. | | Speaker jack | Cracks (plastic Cliff jacks) | Switchcraft 12A (metal). | This is where most owners mess up