The decision to discontinue the TB and TBX models in 2004 was caused by a number of reasons. First, Marshall Amplification PLC needed to concentrate the use of their manufacturing capacity on the growing popularity of Marshall products. Secondly, costs in materials and labor in the UK had escalated, causing the retail price of the AC30TBX to rise to $3200. Sales had started to sag due to these price increases.

A third concern was the additional costs incurred due to the inclusion of the highly complex "Vib/Trem" circuitry in the AC-30TB and TBX models. "Vib/Trem" was an original feature of JMI Vox amps made in the 1960s. The "Vib/Trem" effect was unique to the Vox AC-30. Many amps feature "tremolo." In technical terms, tremolo is "variable amplitude modulation." Simply stated, this means a pulsing of the loudness of the output amplifier at different speeds and depth. This is not a difficult effect to design into a guitar amp. Vibrato, on the other hand is "variable frequency modulation." This involves the wavering of pitch. A much more complicated circuit is needed to create the vibrato effect in a guitar amplifier. Looking at the schematic for a 1960s era Vox AC-30 with "Vib/Trem" in the image below highlights the complexity of this circuitry. The area highlighed in yellow shows the part of the circuit devoted to "Vib/Trem."

Steve Grindsrod, head engineer at Vox in 2004, had many other "clean sheet of paper" ideas for the Custom Classic Version of the AC-30. The inclusion of a "Master Volume" control would allow the new amp to be overdriven at the preamp level without excessive output levels. A series of control panel switches could be incorporated to allow the new amp to not only have "top boost" circuitry, but also offer AC-30 Normal and AC-30 Treble tonalities as well.

The further addition of an "Output Bias" switch would allow for the choice between an 82 ohm (like a vintage AC-30) or a 50 ohm (hotter tone and output) bias resistor.

Another consideration was to incorporate these new circuits into a traditional 1960s JMI Vox style chassis and slider board.

With the design "wish list" in hand, Vox went shopping in 2004 for a manufacturer to produce this new series of amps. This search led to an audio electronics firm in China that had an excellent reputation for producing products with superb workmanship and using quality materials. In addition to making amps for Vox, this Chinese firm was also manufacturing high end stereo components under contract for a famous European "boutique" hi-fi brand.