TRANSITION VOX AC30 "TOP BOOST"
This is a very interesting AC30, which is considered by many VOX aficionados , including myself, as the best sounding of all vintage vox combos. Its rear plate says "TB" for top boost, but it is not the classic top boost with the sixth ECC83 and the bass and treble knobs. This amp is a transition between the classic AC30 and the top boost, having its treble output boosted by a different circuit and not by the addition of another ECC83.
Among the differences between red-copper and grey face ac30, my favourite is the JMI logo. The old JMI logo reminds me the Avengers nursery episode, with its '50s British children educational letters.
The differences between the treble and its two ancestors from my collection are silver speakers instead of electric blue and black moulded vents instead of copper. Anyway I just love each old AC30 and they always take my breathe away. The only one I have difficulties to find is the real top boost with red-copper face/plate as they much rarer then grey face AC30TB.