VOX mini superbeetle 25 stack

first play
VOX AC30S1 COMBO & MINI SUPERBEETLE 25 STACK
24
Guitarist september 2018
its inspiration from the 1960s’ USA-made
Thomas Organ stacks and the British-made
AC-100, with a scaled-down Nutube-
powered head sat on top of a simplified
non-pivoting chrome frame that supports
a 1x10-inch Celestion-powered speaker
cabinet. As with the MV50 heads we looked
at around a year ago, the Mini Superbeetle
may look like a toy, but it’s more than
capable of holding its own with many full-
sized amps, producing 25 watts into its
dedicated cabinet, and up to 50 watts
into a 4 ohm load.
Both amps are dressed in full-on
traditional Vox livery, with black
basketweave vinyl, brown diamond grill
cloth and suitably proportioned gold logo
badges, including an authentic vertical
trapezoid badge for the Mini Superbeetle’s
speaker cabinet. Grey-black control panels
and chicken-head knobs on the outside
of the chassis complete the vintage vibe.
However, underneath the vintage looks
the electronics are thoroughly modern.
The Mini Superbeetle has a pair of small
PCBs for preamp and power stage, with the
Nutube sat on a separate daughterboard,
making it easy to access in the unlikely
event it needs replacing. The Nutube
6P1 is an innovative replacement for
the conventional 12AX7 preamp valve,
developed by Vox’s parent company
Korg in association with VFD specialists
Noritake Itron. It uses VFD (Vacuum
Fluorescent Display) technology, normally
used in displays that tell you how fast
your microwave curry is cooking. VFDs
are interesting because they work almost
identically to valves; they have a cathode,
anode and a control grid to switch display
sectors on and off. Homebrew enthusiasts
have tinkered with VFDs for audio before,
however, the Nutube 6P1 is designed for
audio and effectively replicates the 12AX7
twin triode’s characteristics. The benefits
are a much smaller package that looks like
a glass integrated circuit, with tiny power
consumption and little or no heat, resulting
in a much-increased life – Korg quotes in
the region of 10,000 hours.
As for controls we get knobs for gain,
volume, bass, treble, a level control for the
built-in digital reverb and a speed control
for the Nutube-powered tremolo. There’s
also a small standby switch, linked to a
ferociously bright blue ‘on’ LED that’s
powerful enough to make reading the
panel lettering almost impossible.
On the rear panel you’ll find a socket for
the external laptop-style 19-volt DC power
supply, a pair of speaker jacks with an
impedance switch and speaker-emulated
headphones recording output. A master EQ
switch changes the overall response between
‘deep’ and ‘flat’ modes, to suit the matching
cabinet or larger enclosures, and there’s a
defeat switch for the Euro-friendly auto
power off mode, which turns off the power
if no audio is sensed after a pre-set delay.
The AC30S1’s internals are similar, just
larger. Two main PCBs support most of
the electronics including the valve sockets,
with a smaller daughter board for the amp’s
digital reverb effect. Everything is neatly
wired up and connected by Molex plugs,
making servicing easy if it’s needed.
The AC30S1 gives a
modern interpretation
of the Top Boost
tone wrapped up
in traditional looks
2. The AC30S1 keeps it
simple with a solitary
effects loop and
extension speaker
outlet on the rear
3. Deceptively simple
controls on the AC30S1
access the full spectrum
of Top Boost tone,
with the chicken-head
knobs underlining
the vintage vibe
1. The AC30S1 has a
momentary action mains
power switch linked to
an eco-friendly power
supply, so no clunks
when switching, and the
amp can switch itself off
if there’s no sound for
around 15 minutes
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GIT437.rev_vox.indd 24 08/08/2018 16:06