Dale Sherlock is a legendary figure in Australian amp building and the Fat Head is an icon – albeit a little-known-outside-of-Oz one. Sherlock’s popular mods and MIDI upgrades are killer ways to add extra functionality to an amp, but part of the charm of the Fat Head is that much of this utility, experience and knowledge is built right into the amp.
So what are we looking at here? Well the Fat Head is a four-channel, 50/100 watt monster which sends your sound on an all-analog journey through six tube stages for the two high-gin channels, four for the Edge channel and three for the clean, on through two or four power tubes, depending on mode. Those tubes can be 6L6 or EL34, or a pair of each – actually any octal-based power tube, for that matter.
The four channels are Clean, Edge, Rhythm and Lead, with Clean and Edge sharing one set of Bass, Mid and Treble controls and Rhythm and Lead sharing the other set (along with a Mid Scoop button). There are independent Gain and Volume controls for each channel, as well as a Bright switch for the Clean channel, plus three-way Tone switch and Gain button on the others. Front-panel channel switching is afforded via pushbuttons next to each of the Volume controls. Then there are two selectable Master Volume controls, two selectable Presence controls. and two Depth switches. The effects loop has adjustable Send and Return levels as well as a Series/Parallel switch and it can be selected for each channel via a front panel button. There’s also a Program button for saving your changes, and of course the standard Power and Standby switches.
Aside from the effects loop, MIDI In and Thru jacks, speaker jacks with 4/8/16 ohm impedance switch and effects loop, the back panel also features an additional input jack (especially handy for those who prefer to rack their heads), a Slave output with level control, and Sherlock’s Tube Management System (T.M.S). Part of the genius of the Fat Head is the way the T.M.S. handles power. Thanks to the BIAS REF. pots on the back, you can control the class of operation from Class AB to more Class A or even fully adjustable Simulclass, with any two tubes running Class AB and the others running Class A. Sherlock prefers JJ12AX7s for the preamp tubes and Svetlana winged C or JJ 6L6s and EL34s in the power stage.

Control again comes into focus when you consider that the Fat Head includes Sherlock’s Midi Mod built in, allowing you to control various features via MIDI. Sherlock offers a dedicated Fat Head 10 button foot controller for this purpose, connected with a 7-pin MIDI cable and phantom powered by the Fat Head. It can be used with any MIDI application, which is handy indeed because the Fat Head’s MIDI control allows you to change channels, control the effects loop, the dual presence and master volume controls. The Fat Head controller is a good option for those who don’t want to use a full-blown ultra-floor-encompassing MIDI floorboard, so as long as you’re not scared of learning some basic MIDI, you’ll be alright.
Construction quality is pretty spectacular, with cabinets made of 18mm thick C grade Australian plywood, covered in black 30 oz Bronco Tolex (other Tolex colours are available as a custom option). The CNC hole-punched 1.6mm steel chassis with welded seams is finished in gloss black powder coating and augmented by a frankly freaking cool tinted perspex front panel which shows off the tubes. Components include Sprague Orange Drop polypropylene capacitors and Silver Mica for the higher values, while pots are by CTS and channel switching is via NEC sealed relays with gold-plated contacts. A special circuit mutes channel switching pops for an inaudible split second. The PCBs are 1.6mm thick fiberglass, double-sided, plated through-hole, with 3 oz copper tracks.
So how’s it sound? Monstrous! What makes the Fat Head so successful is the way it can be configured to very exacting specs via the Presence, Depth, tone and Gain boost or Bright controls. There’s a kind of direct punch, tight low end and glassy treble that really kicks on the Clean channel, especially with my Seymour Duncan Quarter Pounder-loaded Telecaster, and this is great for gritty country and hard-edged metal cleans, but this channel can also be coaxed into smooth jazz too by turning off the Bright switch and picking up a humbucker axe. Flip the bright switch back on, dip the mids and use the second position on a Strat and you get a great zingy clean tone, perfect for funk or ringing pop clean tones.
The Edge channel has more grit and girth, but I find it especially fun kicking out barky classic rock rhythm tones with humbuckers. Meanwhile lower treble settings lead to a sweet Strat/Marshall-type blues rock tone but with tighter bass thanks to the 6L6s of the test model (El34s would play this up even further). This channel is also great for old-school Santana-style hyper-dynamic neck pickup soloing. If you’re into more dynamic lead sounds and you aren’t so concerned about high-gain, the Edge channel is great for lead.
The Rhythm and Lead channels can be configured for utterly savage scooped-mid death tone with ultra-sharp highs thanks to the three-way Tone switch, or a fatter, fuller, warmer “Bad Horsie” type growl which works great for late 70s/early 80s Sunset Strip rock. You can even get some rather Djenty sounds which take advantage of the extra low end of the Depth switch.
The level of available distortion is pretty intimidating and if you’re into the whole ‘crank the gain to 11 and chug out’ school you’ll find that the Presence control and the Depth and Tone switches will give you a clarity that is very, very hard to attain with most high gain amps. But that same quality can be pretty unforgiving for other styles, so if you prefer more of an overdriven rather than mega-distorted tone, go easy on the Tone switch. It can be pretty harsh on the ears when misused. Set it to its least-trebly setting, crank the Gain, reduce the treble and boost the mids for a singing shred lead tone which reminds me of the best of the Shrapnel Records era of shred: plenty of compression, sustain and midrange power. And there are lots of great harmonic overtones screaming out when you really crank the power amp – if you’re brave enough or sound-insulated enough to do so.
There really isn’t anything the Fat Head can’t do – especially considering the different power tube options, MIDI control and the wealth of tone-sculpting. It’s not cheap, but think of it as valuable rather than expensive. It’s a fully professional piece of kit designed for serious players, and I can imagine it being especially at home in the hands of a player who needs to cover a country gig one night, a metal one the next, and a jazz or pop session in between. Yet its metal tones are so authentic and distinctive that it would also be perfect as the heart and soul of a thrasher’s rig.