The FAT HEAD represents the culmination of years of research and development invested by Sherlock Amplifiers in creating an amplifier with an entirely analogue tube powered audio path that can be shaped and controlled with almost infinite potential. Covering sounds from bell like clean to classic crunch rhythm to heavy modern rhythm to creamy super hi gain, it is the most flexible, best sounding, all tube amplifier ever made.
The FAT HEAD's features and controls have been carefully chosen and fine-tuned to bring you pristine tone and unprecedented versatility. 4 channels, each with 3 voicing options plus a mid scoop option gives you a total of 24 sound possibilities, not taking into consideration a highly effective EQ. And that's just the preamp! Then add the option of Master Volume, A or B, the uniquely voiced Presence A or B, each with a depth button, makes 192 sonic combinations. Then with the addition of a multi effects unit to the effects loop, operating in either series or parallel, gives you … well, you get the idea.
The use of state of the art tube circuit design, coupled with high quality components used throughout, puts the FAT HEAD in a league of its own in both performance and reliability. We are yet to find anything that comes close to creating such an expansive range of high quality, exceptionally musical sounds, let alone delivering it with such a staggering level of flexibility and controllability. So whatever your style of playing, the FAT HEAD has your sound!

Channel Description
The Clean channel provides an array of clean tones that fatten with a subtle compression as the gain setting increases. With the Bright switch in the "Normal" position, the clean channel is smooth and mellow. Shifting the Bright switch to the "Bright" position, the guitar's high harmonics are boosted for sweet sounding rhythm playing. The "More Bright" position gives exceptionally crisp and responsive tones with extra brilliance. A little tweaking will give you access to round Jazz tones, bright spanky funk sounds, through to sounds suitable for a dark smoldering metal epic.
The Edge channel takes over where the Clean channel leaves off; low gain settings are clean with the addition of a slightly edgier quality. With the voicing switch in the "Normal" position, increasing the Edge Gain control is like a tour of cool, super smooth Blues tones. The 'Bright' position of the voicing switch adds a shimmering jangle suited to 'Britpop' type sounds. In its third position, the voicing switch increases the tube breakup for a sound that sets a new standard in classic hard rock tones. Engaging the Gain switch on the Edge channel takes you beyond turning up to eleven! No matter what your preferred setting, the Edge channel is alive and dynamic, extremely responsive to every nuance of your playing.
The Rhythm and Lead channels of the FAT HEAD are this amps strongest suit, providing an absolute arsenal of classic and modern high gain. They cover a staggering amount of variation in tone, from hard rock to utter heavy metal meltdown. Each of the two channels have there own 3-position voicing switch, a push button 'Gain boost' switch for EXTRA gain, plus the Mid Scoop option. These tone shaping tools can be set to make the two channels sound very similar with only subtle variation, or set to give two wildly different flavors. Whatever your tonal preference for high gain sounds or even how high you like to go, the FAT HEAD maintains a unique harmonic richness and remains articulate and musical.

Like many of the features of the FAT HEAD, the midi control of the functions of this amp sets it apart from all the rest. Simply with the Fat Head’s built in Midi Mod, its is possible to combine, sections of the Fat Head’s features, for example the rhythm channel with the Effects loop in, using the Presence A, and the Master B, saving them, assign them to a patch number and recalling that same combination. Even the settings in your effects unit can be recalled by hitting one switch on the Fat Heads Foot Controller. How many times can I do this you say, 100 times, i.e. the Fat Head will save and recall 100 combinations of it features. And it’s so simple to do.

  1. Select a patch number on the Fat Head Controller or any MIDI Controller.
  2. Select the amps channel or function using the corresponding buttons on the Fat Head.  The led or leds on the Fat Head light up to indicate which channels or functions have been selected. 
  3. Press and hold the “Prog” button for 2 seconds. The Fat Head will now save this combination and assigned it to the patch number selected on the Foot Controller (in step 1), and your done.

To check your programming has been successful, select another patch number on your Midi controller and then select the one you selected in step 1, and the Fat Head will recall your programmed combination.
Please note that due to the sound possibilities of the Fat Head a simple footswitch is not provided as this would severally compromise the sound possibilities that are archived by the MIDI Controller. However if a Full Blown MIDI Controller freaks you out, we have designed a simple 10 button Controller for the job.

A Closer Look...


(Patent 2002100984)

Developed by Sherlock Amplifiers, the TUBE MANAGEMENT SYSTEM is a straight forward, easy to use TUBE BIASING SYSTEM, designed to allow the user to:
Check and adjust Individual tube bias.
Install new tubes and bias them correctly.
Identify and replace faulty tubes, and maintain the power stage of the Fat Head tube amp for optimum performance. (Please note that this is all done without any external meter or other equipment!)
The 3 main areas of operation are:
Tube biasing using 4 individual bias pots.
Visual monitoring of tube bias with 4 sets of Bias Status LED's.
Protection and damage isolation of the amp in case of tube failure with 4 individual fuses.
So this means you never have to take your Fat Head to a Tech for a re-tube...you can do it yourself!


One of the reason the Fat Head sounds so good is because for the first time the user has total control over how the amps Power Tubes are biased thanks to T.M.S.
Tube amps require there output tubes to be correctly biased in order to achieve the best tone and longest tube life. Problems such as overheating, premature tube failure, and shortened tube life, are also associated with incorrect tube biasing. The T.M.S. System incorporates 4 bias pots, (one shown only), one for each tube, accessible at the rear of the Fat Head amp. These can be adjusted with a small screw driver by the user. Evenly balanced intensity of the BIAS IND. LED's indicates a correctly biased tube. This means that at glance, every time you use the Fat Head you can check the bias on you power tubes!
Incorrect tube biasing and all its problems is now a thing of the past!


But wait it gets better, Due to the tonal and distortion differences of biasing on tube performance, Sherlock Amplifiers has provided a means for the user to set the desired tube bias current and therefore threw tweaking, find the output tubes "sweet spot". The BIAS REF. pot sets the bias current for the tubes. This pot has a range starting from 20mA and goes up to 50ma in 5mA steps printed around the pot.
The user would preset this pot using a small screwdriver to the desired tube current as specified by tube manufacture or the sound required. Then, each tubes BIAS POT is adjusted for evenly balanced intensity on each tubes BIAS IND. LED's. All tube currents would now be set to the BIAS REF. setting. More on T.M.S. on the Testimonials page

Power tube possibilities

Now this can open up some tonal possibilities that were impossible before, like using 6L6 and EL34 together or anything else with an Octal base like 6550's. If that still not enough,  with T.M.S. you can control the output tubes Class of operation from class AB to more class A and even have true, adjustable Simulclass. (Any 2 tubes class AB and the other 2 tubes class A) its total wild!
As an example of the flexibility of T.M.S., the Fat Head could be fitted with 2 x 6L6 tubes, and 2 x EL34 tubes. The BIAS REF. pot would be set to 35mA, a good average for both the 6L6’s and EL34’s and the Individual bias pots would be adjusted for evenly lit BIAS IND. LED's. Both sets of tubes would be running in class AB.
Now onto the Simulclass possibilities.
Suppose you want to run the 2 x 6L6’s closer to class A. Set the Bias Ref. pot to say 40-45mA and adjust the BIAS POTS on the 2 x 6L6’s for evenly lit BIAS IND. LED's and you done! The opposite can be done as well. Or all can be set closer to Class A or all can be set to class AB as we started.

Have a Listen...

Audio Clean Jazz sample Smooth Jazz. Channel 1
Audio Heavy Rhythm 1 sample Straight of mic'ed Vintage 30 Cab. Channel 3
Audio Heavy Rhythm 2 sample Heavy Modern Rhythm Channel 3
Audio Rhythm 1 sample Classic Rock Riff and small solo. Channel 3&4
Audio High gain Solo Floydian Hi gain solo. Channel 4

You Tube Clips...

Damian Murdoch Trio - Jump Rope with Electric Wires

 i built the sky - Translucidus (Featuring Sithu Aye)

Ormsby & Ellis Guitars Show 2013 - Setting up for the Show

Ormsby & Ellis Guitars Show 2013 - Time for Shred

Karnivool- Themata Cover

Daz Recording Album


Check out our testimonials page for the Fathead
Also check out the Australian Mixdown review (Dec 2002)
http://iheartguitarblog.com has kindly done a review on the Fat Head amp.
Thank you very much Peter Hodgson for this great review!

Tech Specs

  • All tube technology, no solid state components in signal path.
  • 4 channels, Clean, Edge, Rhythm, and Lead (midi switchable).
  • Gain & Volume for all 4 channels.
  • 6 tubes stages for the HI-Gain channels, 4 stages for the Edge, 3 stages for Clean
  • channel.
  • Separate EQ control, Bass, Mid & Treble for Clean/Edge channel, and for Rhythm/Lead channel.
  • Mid scoop for all 4 channels. (midi switchable)
  • 3 position bright switch for the Clean channel.
  • 3 position voicing switch for each of the 3 Dirty channels.
  • Gain boost button for each of the 3 dirty channels
  • Dual Master Volumes (A or B) for volume boosting. (midi switchable)
  • Dual Presence, (A or B) (midi switchable), uniquely voiced with dual Depth buttons.
  • Effects loop bypass control (midi switchable)
  • Series/Parallel effects loop, with send and return level controls.
  • 2 power modes, 100w / 50w, using 2 or 4 power tubes (part of TMS).
  • Choice of power tubes fitted, 6L6 or EL34 tubes or a paired combination.
  • Tube Management System (TMS) Power tube Bias status indicator LED's, Bias adjustment Controls and cathode fuse for each power tube. Power tube set switches, i.e. tubes 1 & 4 on (50watt), or 2 & 3 on (50 watts), or all 4 tubes on (100watts), or all 4 off for pre-amp use only.
  • Line out (slave) with level control.
  • Two speaker outputs (paralleled).
  • Speaker Impedance output selection to suit any speaker combination (4, 8, or 16 ohms).
  • Midi in and Midi through sockets. Midi In also supplies phantom power for Controller.
  • Dimensions: Fathead Amp cab length 67.5cm, height 26.5cm, depth 25.5cm, Weight 26kg.
    (this is the overall size including handle, feet and corners.)
  • Fathead and /or controller in freight box: Length 75cm, height 37cm , Depth 43cm
    Weight 28kg (inc packaging)

Build Quality
As with all Sherlock Amplifiers products they are assembled by hand, ensuring the highest standards of construction which means, they sound fantastic; they are extremely reliable and will last a lifetime. However we have gone that one step further with the Fat Head amp.
Starting with the externals, the cabinets are made from C grade Australian Plywood 18mm thick, covered in black 30 oz. Bronco Tolex as standard (other tolex colors available upon request) with quality hardware fitted.
A visual enhancement is achieved with the Fat Heads tinted Perspex front panel revealing the heart and soul of this amp, its tubes. Another first for the evolutionary design of tube amps, done by Sherlock Amps almost 15 years before any other tube amp company.
Next is the CNC hole punched, 1.6mm steel Chassis with it’s  welded seems covered in a gloss black powered coating which is hand polished before the assembly of its component. Controls are logically laid out across its front and rear panels with minimal lettering for reduced panel clutter.
Now the Electronics is where this amp has been refine and tweaked again and again. Starting with the resistors, we use Hi-stability MF 1/2 watt mainly throughout the amp, the best we can get.
Signal path capacitors are fast responding polypropylene (Sprague Orange Drops) and Silver Mica for the higher values. These capacitors are used throughout for inter-stage coupling and tone shaping in the Fat Heads circuitry.
Electrolytic's are Illinois and are used throughout the Fat Heads power supply and are also used for inter-stage decouple.
Channel Switching is achieved by NEC sealed relays with gold plated contacts for minimal signal loss. Channel switching “pops” are muted for an inaudible split second by a special circuit controlled by the amps built in Midi Mod as the channels are switched from one to the other.
Pots are special quality CTS for long life with 3/8” brass bushing and ¼“ shafts ensuring strength and reliability. Knobs are solid chrome plated knurled brass (Tele Style).
The Fat Heads PCB's are 1.6mm thick fiberglass, Double Sided, Plated through Hole, with 3 Oz. copper tracks making them extremely reliable. Designed by us and made in Australia, these PCB's are a work of art in themselves and have evolved from 6 previous designs stages.  The PCB designs are very important because this is were the Fat Heads circuitry is laid out inside the chassis. pcb

Every amplifying stage has been positioned for perfect operating stability, minimal inter-action from other stages, low noise, low hum, low cross talk, etc., ensuring fantastic performance and best tone.
Another advantage of maximizing the Fat Heads PCB design are that there is minimal internal wiring with all its disadvantages like increase noise, instability, connector reliability and cost. In fact the few connections that could not be accommodated by the PCB are wired and soldered directly for the highest reliability. There are only a few connectors used that are absolutely necessary from a service perspective.
Moving closer to the heart of the Fat Head, we have the cool running, generously sized transformers.
Firstly the power transformer is a custom hand made design proving all the necessary voltages for the Fat Heads circuitry to operate from. The output transformer is also a custom hand made design using grain oriented steel and double insulated copper wire for the highest reliability.
And finally the Tubes. For the Preamps we have found that the Fat Head sounds best with JJ12ax7. We spend time selecting by ear the best tubes for low noise and best tone in all the Fat Heads stages. And for the power stage we us 6L6 or EL34 Svetlana winged “C” or JJ's for there tone and reliability. Tubes are matched and individually biased perfectly with the Fat Heads TMS. Biasing system.

So from what you have just read, it should now be obvious that the Fat Head is no ordinary amp, and we ask that if you are in the market for a state of the art tube amp please enquire about a demo of the Fat Head.

Fat head midi-4-100 head - RRP AU$3995

How to Purchase

Accessories for the Fat Head:

Fat head foot CONTROLLER

Simple 10 Button Midi Controller designed to operate the Fathead Tube Amp. It is Phantom powered by the Fathead.
Can be used in any MIDI application
RRP AU$300

Product Profile
midi cable

7 pin midi cable

Hand made using heavy duty cable and Neutrik plugs this cable connects the Fathead Foot Controller to the Fathead. 7 pin, 5mt long.
Custom lengths available on request.


Product Profile


Amps & Accessories

Special offer:
Free FAT HEAD Tshirt
with every amp sold!


i heart guitars
has kindly done a review on
the Fat Head amp.
Thank you very much
Peter Hodgson for this
great review!

Some brief testimonials....

"My attention was immediately drawn to the Fat Head. Just awesome. I couldn't get over just how flexible this thing was." more...

"The advantage is that you can change tubes and bias them yourself without having to leave your amp with a tube tech.
It works perfectly, saves time, money and is just plain brilliant." more...

"I’m just writing to let you know that this amp you have built me is hands down the best amp I’ve ever heard and used and I just can’t stress how good it actually is." more...

"I am writing you because I have a client here in the US by the name of Mike. I saw him last night and he asked me to play this amp that he gotten called a Sherlock. I agreed and from the first chord I was hooked. The first thing that came to my mind was I have to sell all my Mesas and buy this amp." more...

"I don’t usually go around endorsing products but this is such an understated amp and there is so little information out there about it that I feel compelled to let people know about it." more...

Check out the FAT HEAD gallery below.
Vintage Reverb 30 - Click to Zoom
Click to Zoom