Crazy Tube Circuits Ziggy

The Crazy Tube Circuits Ziggy is a British-flavored dual overdrive/distortion pedal: two separate gain channels in one box, one low gain and one high gain, each with its own controls and its own footswitch, selected by a silent relay true-bypass switching circuit¹. Where most overdrives lean on an opamp for their gain, the Ziggy is built from cascaded discrete MOSFET gain stages, which the maker says are designed to respond like a tube amp with ultra touch sensitivity¹².

The amp targets are classic British territory. MusicRadar's reviewer, Trevor Curwen, describes the pedal as designed to give the sound of two classic Brit amps, the AC30 Top Boost and the JTM45³. Crazy Tube Circuits says the low gain channel is voiced after a late 60s Super Bass, while the high gain channel sounds and responds like a late 70s Master Volume British amp¹.

The controls

The v2 gives each channel its own control set, and the two channels are voiced differently, low and high gain, for what the maker calls ultimate versatility¹. Delicious Audio's buying guide lists the v2's controls as Input Gain, Output Master, a three-band EQ (Bass, Mid, Treble), and a Presence switch that can either attenuate negative feedback or boost high-end frequencies⁷.

Two details of the gain knob are worth knowing as a player. First, it has an "off" position at fully counterclockwise, and turning it just a little goes immediately from no sound to the first audible sound. An independent circuit analysis found this was deliberate, mimicking the gain knob behavior of most tube amps². Second, the voicing trick is real circuit behavior, not marketing: the gain pot carries a 22nF treble bleed capacitor, which, as the same analysis puts it, "actually does all the 'voicing' thing"².

History and versions

The original Ziggy was a single-channel overdrive with volume, tone and gain knobs. In a 2013 demo video, Pete Thorn walked through it: "Here you've got a volume, a tone control that acts like uh very much like a presence control"⁸. An updated white and gold version added a two-position gain switch, whose higher gain setting has extra bite and sustain, making it suited to lead sounds².

The v2, announced in January 2018 and available that April at €199, rebuilt the pedal as the two-channel dual overdrive/distortion sold today⁵. Delicious Audio described it at launch as a two-channel Plexi-style distortion and one of the company's most popular pedals⁶. The current webstore price is €189.00¹.

Inside the circuit: three BS170 MOSFETs

The Ziggy's circuit is what sets it apart from most overdrive pedals. An independent teardown of the pedal, reverse-engineered by its own designer Giorgos Ziotas with a schematic drawn by Nocentelli and the layout verified by Hozy31, found three BS170 MOSFETs arranged as cascaded discrete gain stages².

The analysis notes that, unlike most overdrives, the pedal does not feature a "mojo" opamp but cascaded discrete MOSFET gain stages². Supporting details from that teardown:

• 9.1V zener diodes (BZX55C) from gate to source protect the MOSFETs from static².
• Static protection diodes appear on only 2 of the 3 BS170s: the first MOSFET needs protection from almost everything, and the second because of a risk of a spike during switching².
• The two-position gain switch simply adds 2 resistors in parallel going to ground, and should be an On-On switch².

The same analysis compared the topology to a familiar benchmark: the Z.Vex Box of Rock. The finding was that the Ziggy is very similar in topology, with cascaded gain stages, but with a different gain and tone structure yielding different sonic qualities, for example touch sensitivity².

What reviewers said

MusicRadar's Trevor Curwen reviewed the Ziggy and found the gain knob central to its character: starting with mild overdrive and a bright tonality, it gradually loses its trebly edge and gets crunchier, up to midway reminiscent of a Vox with dirt, then cranked Marshall territory³. His overall verdict:

The review was not entirely uncritical: alongside that praise, MusicRadar listed four-screw battery access among the pedal's drawbacks³.

Pete Thorn's 2013 demo of the original Ziggy covers the control set and the range of drive tones, from the low-gain jangle through the higher-gain crunch⁸.

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Questions