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  • Castledine Electronics Magical Mystery Box

    By Phil O'Keefe |

    Roll up for the Mystery Box!



    In September of 1965 the Thomas Organ Company in California began making Vox-branded amplifiers under license in the USA. From this point forward, the US and JMI-built UK versions of the amplifiers diverged, and different models with different names and circuits were offered in each country. The US was the first to hit the market with solid-state Vox-branded amplifiers, and these designs heavily influenced the design of the UK-built UL 4 and UL 7 series hybrid amps, and shortly thereafter, the first UK-built fully solid-state Vox amplifier designs, which were marketed in Europe from 1967-1969. Three guitar amps in this UK-built solid-state line shared identical two-channel preamp circuits and only differed in their power amplifier sections, with different output power levels provided for each. The Castledine Electronics Magical Mystery Box pedal under review here is based on the Brilliant channel preamp circuit of these three UK-built solid-state Vox amplifiers - the 30W Conqueror, 50W Defiant, and 100W Supreme.  



    What You Need To Know

    • The Magical Mystery Box is based on the Brilliant channel of the UK-built Vox Conqueror solid-state amplifier, which was first introduced in 1967. An original Vox Conqueror amplifier was used for reference in the creation of the Magical Mystery Box.
    • The name of the pedal is an obvious tip of the hat to The Beatles, who used Vox Conqueror amplifiers (there's some debate that the amps they used may actually have been the similar-looking yet more powerful Defiants) during the Magical Mystery Tour / White Album era, as can be seen on the promotional film shot at the Saville Theatre on November 10 1967 in London for the song Magical Mystery Tour.
    • The Magical Mystery Box is built by hand by Stuart Castledine in relatively small batches, and has featured slightly different cosmetics for each of the production runs. The current batch is gloss black with white lettering, and the name of the pedal is represented with the same font as you'll find used on the cover of the Magical Mystery Tour album by The Beatles. Segmented white rings surround the chrome control knobs, both of which are reminiscent of what you'll find on the vintage Vox solid-state amps. The overall presentation is very classy looking.  
    • The Magical Mystery Box is a rather large pedal, but understandably so considering the amount of switches and controls it has. It measures approximately 7.4" W x 4.8" D x 2" H. Four rubber feet are provided with the pedal, but are not pre-attached. A cool black cloth drawstring bag is also included.
    • Internally, the construction utilizes through-hole components, and the quality of the workmanship is excellent. There are no internal switches or trim pots to concern yourself with.


    • Volume, Bass and Treble knobs on the Magical Mystery Box provide similar functions to the amps, and are active whenever the pedal is not bypassed. The overall tonality of the pedal is bright and clear, with a distinctive treble edge to the sound that is very reminiscent of the vintage Vox amps, and otherwise very hard to duplicate. The volume control can provide you with anything from completely clean tones, with increasing levels of volume and overdrive available as you turn it up towards the higher range of its travel. The overdrive sound is also bright in nature, with a nice gritty tone that is very similar to the rather unique sound of the original amps.
    • For even more over-the-top distorted tones, a built-in Distortion circuit is provided, just as you'll find on the amps. This single knob distortion offers heavier, thicker tones than the volume knob overdrive is capable of, as well as a slightly darker crunch tonality than the basic sound of the pedal. Again, this closely replicates the behavior of the amps on which the Magical Mystery Box is based.
    • Just as with the original amplifiers, the Distortion circuit utilizes germanium transistors - in this case, a pair of metal-can AC125 PNP transistors.


    • One of the more unique features of the Vox amplifiers from this era is their built-in MRB circuits, and you'll find an extremely convincing reproduction of that circuit in the Magical Mystery Box. This Midrange Resonant Boost circuit provides a boost at one of three pre-set frequencies, with a three-position knob / switch provided to select them with. A classic example of the MRB sound can be heard on the piano part of the song 
      it is particularly audible on the very last chord of the song as the knob is manually switched between its three settings. Internally, a custom hand-wound inductor is used on the Magical Mystery Box, and the overall character of the boost is, again as with the MRB circuit on the amps, similar to a fixed wah; in fact, the Vox MRB is a direct ancestor to the modern wah pedal that most guitarists are familiar with.


    • There are three footswitches on the Magical Mystery Box. On / off switching for the pedal is true bypass, and is handled by the center footswitch, which is labeled "Effect." To the left is a footswitch for engaging the Midrange Resonant Boost feature, which is labeled MRB, while the third switch on the right side of the pedal labeled Dist. allows you to kick the built-in Distortion function on and off.
    • A small LED illuminates to indicate when power is applied. LED status indicators for the main on / bypass "Effect" switch, and for the MRB and Distortion footswitches are available as an extra-cost option. If installed, the LEDs for the MRB and Distortion show the status of those switches, regardless of whether the main Effect footswitch is active or bypassed.
    • The Magical Mystery Box runs on 9V DC, and has a standard center-negative 2.1mm power jack located at the top of the pedal, which is also where you will find the 1/4" input and output jacks. Current draw is less than 5mA for the standard model, and less than 20mA if you get the version with the optional LED indicators for the footswitches.



    • Battery power is not an option, and you'll need to provide your own power supply as one is not included with the pedal. To be fair, many users will already have a suitable pedalboard power supply, and adapters differ from country to country, so it's generally easier and less expensive to source the correct supply locally than have it provided by Castledine Electronics.
    • Unlike the vintage amps, the pedal doesn't include reverb. Since the tremolo of the amps was part of the Normal channel and not the Brilliant channel that the Magical Mystery Box is based on, the tremolo is also not included. Unlike the unique sound of the amps, and the rare MRB feature, the reverb and tremolo shouldn't be too hard for Beatles fans to replicate via other pedals.
    • LED indicators for bypass and the MRB and Distortion circuits are extra-cost options.
    • It's not an inexpensive pedal and it's built in small batches in the United Kingdom, so you're not likely to find it sitting at your local US store waiting for you to try it out, but Castledine makes purchasing it as easy as possible and they were an absolute joy to deal with; they were very helpful and kept me apprised throughout the ordering, assembly and shipping process - all of which went much more quickly than I expected.  



    In the effects pedal industry Stu Castledine of Castledine Electronics has a reputation for really knowing his stuff, especially when it comes to replicating rare vintage equipment, and spending five minutes with this box will only reinforce that, and completely dispel any doubts you may have had if you're one of the rare few who happened to have held any previously. The research and care that went into this Magical box are readily apparent. The component quality and construction are all first-rate, and there's no question that the sound is as authentic as anyone could possibly want from a pedal inspired by those rare, early solid-state JMI Vox amps.


    Short of hunting down and spending big bucks on a rare and relatively unreliable UK-built vintage Vox Conqueror, Defiant or Supreme there's no better way to get the classic sounds used by the Beatles on some of their coolest songs from the Magical Mystery Tour and White Album era. These amps were also used on some of the material from the Rolling Stones from the same general time period, so Stones fans will also want to take note. The build quality of the Magical Mystery Box is as good as it gets, and it provides some very well-known tonalities that are very difficult to get anywhere or any way else. Roll up for the Mystery Box - it's coming to take you away! But you're not taking this one away from me - I purchased the review unit, and it's not going anywhere!




    The Magical Mystery Box is available direct from Castledine Electronics.

    Magical Mystery Box, without footswitch status LEDs - £ 225.00 ($351.24 US, as of July 2, 2015)

    Magical Mystery Box, with footswitch status LEDs - £ 239.00 ($373.09 US, as of July 2, 2015)


    Castledine Electronics website



    Castledine Electronics Magical Mystery Box product web page

    Castledine Electronics on Facebook






    phil-3eaec998.jpg.136f62c92eafba0a69d52a0e6e7abd40.jpgPhil O'Keefe is a multi-instrumentalist, recording engineer / producer and the Senior Editor of Harmony Central. He has engineered, produced and performed on countless recording sessions in a diverse range of styles, with artists such as Alien Ant Farm, Jules Day, Voodoo Glow Skulls, John McGill, Michael Knott and Alexa's Wish. He is a former featured monthly columnist for EQ magazine, and his articles and product reviews have also appeared in Keyboard, Electronic Musician and Guitar Player magazines.  

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