Fuzz Machine

Popular wild 70's fuzz tone machine

 

 

 

The Fuzz Machine rack fuzz effect module compares to the vintage fOXX Tone Machine.  The Fuzz Machine is a wild and chewy fuzz with a switchable octave up.  Turn it up and lose control, or ride it hard and make it sing like Peter Frampton, Robert Fripp, Billy Gibbons, Beck, Tool, Sonic Youth, Nine Inch Nails, and numerous other fuzz masters have done.

 

Description

The GT Fuzz Machine compares to the fOXX Tone Machine.  The Tone Machine was introduced in 1971 and was made until 1978.  At some point, there was also a reissue that was sold for a brief time.  The Danelectro French Toast is also a version of the circuit.  There are other clones, too.

 

The Fuzz Machine is a wild and chewy fuzz with a switchable octave up.  It is similar to the Super Fuzz, Fender Blender, and Octavia octave fuzz pedals.  It has been used by Peter Frampton, Robert Fripp, Billy Gibbons and later bands such as Tool, Sonic Youth, Nine Inch Nails, and Beck.

The original had Sustain, Tone, and Volume controls, similar to the Big Muff Pi, although with a different overall sound.  There was also a switch to turn the octave up on and off.

The fuzz is pretty aggressive, and with the octave added in it can become a face-melter and cuts through the mix for leads and solos.

The colors of the original pedals varied.  There were also a couple of minor circuit tweaks at some point, but it seems unlikely that the circuit changes were coordinated with color changes.

The later version of the circuit used the same components as the original circuit, with a couple of minor tweaks in values, resulting in a bit more fuzz and a Tone control that moved control of the harsh highs down a bit toward the midrange.  The overall character and tone remained much the same.

The originals used 2N3565 transistors, although perhaps a few units used BC237B transistors instead.  Both transistors are medium gain.  The early units used transistors with gain levels at the low end of their range, and the later units used transistors at the higher end of their range.  In fuzz circuits, the distortion is so extreme that it usually doesn't make much difference what transistor is used, as long as the gain levels are in the right range.  

Both the 2N3565 and BC237B transistors are long out of production, but still somewhat available.  But it may be challenging to find sets of 2N3565 with the right gain ranges to match the later higher gains.  While the transistor model probably has little impact on the tone, the 2N3565 is a popular fuzz transistor that has been used in several good fuzz pedals, and we use them in the Fuzz Machine.  We have options noted below for the transistors.  If you have a preference for the earlier lower gain or the later higher gain, we'll use 2N3565 transistors with the correct levels if we have them.  If we can't find matched sets of them, particularly for the later spec range, we can switch to different modern transistors matched to either gain range.  Again, it's more the gain range than actual transistor model that matters, so this is more a matter of splitting hairs than having an audible impact.  Your choice, of course.

The original Tone Machine has a switch to turn the octave up effect on and off.  We have added a third position for this switch in our Fuzz Machine.  In addition to On and Off, there is a Custom Off position.  Without getting too far into the details, it is like the normal Off position, but it also switches another component in the circuit that tweaks the fuzz/distortion a little bit, providing a nice alternative voicing for the fuzz portion of the tone that remains when the octave is off.

Note that the original circuit had a tiny design flaw that caused an audible pop when the Octave was switched on.  We correct this problem to remove that pop.  It has no impact on the sound/tone other than removing that pop.

The diodes in the circuit were germanium 1N34A.  The actual model makes very little difference, as long as they are germanium diodes with the appropriate forward voltage values.

A lucky accident caused me to turn a FuzzMachine from nasty, in-your-face fuzz with an octave into a nasty, greasy overdrive with an octave, which I like much better that the original fuzz version.  The OD version is sort of like a classic Marshall amp OD, with a layer of thick axle grease spread on it, with an octave up switch.  It's a little on the dark side, like the Darth Vader of OD.  It is *very* different from the original circuit's sound.  It doesn't really compare to any other OD I can think of.  My mistake is offered as a switchable option, and well worth considering.  The controls still do the same things, so you can still feel the Foxx Tone Machine hiding in there, but it's a different beast altogether.

There is only one configuration for the Fuzz Machine, but with a few options.  You will need to select between the Early and Later versions of the circuit.  The Octave switch will come standard with the third setting described above.  Other than that, the standard configuration is true to the original circuit unless you choose other options.

 

 

Configurations

  • Fuzz Machine - Compares to the fOXX Tone Machine

       

 

Options

  • Early or Later Spec - Select transistors with the gain range for the original or later version of the Tone Machine, along with a couple of minor tweaks that are different between the two versions.  Other than transistor gain, the main difference is a different range of Tone control.  The later version gives a little better control of the highs.  By default, we use the Later spec.
  • Transistors - We will use the same 2N3565 transistors as the original circuit, if we can find sets of them that match the gain range of the Early or Later spec that is preferred.  If those are not available we have other options.  Here is the list:
    • Early 2N3565
    • Later 2N3565
    • Early spec modern transistors
    • Later spec modern transistors
    • Early BC237
    • Later BC237
    • In between BC237

Early 2N3565 is the default.  It is difficult to find a set of 2N3565 for the Later spec, so if you want Later spec we'll probably use 2N5088 or 2N5089, more modern transistors that will still give you the Later spec tone.  2N5088 and 2N5089 are great fuzz transistors, better in our opinion than the ones used in many of the classic fuzz circuits, and a GT favorite for fuzzes in general.  Note that switching the transistors or even the HFE has little effect on the tone.

  • Switched Mids Control - This adds a switch that changes the Tone control.  One position of the switch will give you the original Tone control (Early or Later spec).  The second and third positions on the switch move the control of the highs further down into the mids, taming the highs a bit but also perhaps not cutting through the band mix as strongly.
  • Clipping Switch - The fuzz is in part created using germanium clipping diodes.  This is a key part of the overall tone.  If you prefer a bit less fuzz, we can add silicon clipping diodes so you can switch between the two.  We'll use 1N34A diodes like the original as long as we have them but will switch to another germanium diode if our 1N34A diodes are out of spec, like many of them are.  They are often counterfeit or scrap quality parts when we get them these days.
  • More Bass - If you would like the Tone control to have a bit more low end available, select this option.  We also change the size of the input capacitor to allow a bit more bass into the circuit.  Perhaps not such a big deal for guitar, but maybe more useful for bass players.
  • More Noise - The original circuit uses several electrolytic capacitors that can add a bit of noise to the circuit.  Of course, some of that is kinda, sorta part of the character of the tone.  By default, we will use quieter film caps.  This has no direct impact on the tone, other than possibly preventing that little bit of noise.  If you want the original capacitors, select this option.
  • Less Noise - The gain produced by the transistors to create the fuzz comes with a bit of noise.  We can add a couple of small noise capacitors to cut out some of the very top-end noise this produces.  You'll lose a touch of highs.  We do not include these by default.  If you want them, select this option.
  • Carbon Comp Resistors - The original circuit used carbon comp resistors.  They add a bit of noise, sort of a "good" noise that some of us like in a fuzz.  It's sometimes not a change you can clearly hear.  By default we use metal film resistors which are quieter (and cheaper).  If you prefer carbon comp, select this option.
  • OD Switch - Switches on my "happy accident" that changes the pedal from a nasty fuzz to a greasy OD.  We really like it here, better than the original fuzz version.

 

Front Panel

  • On/Off indicator LED
  • Sustain control
  • Tone control
  • Volume control
  • Octave Switch
  • Mids Switch (optional)
  • Clipping Switch (optional)
  • OD Switch (optional)

 

Rear Panel

  • Audio In
  • Audio Out
  • On/Off Footswitch
  • On/Off Override
  • DC Power
  • DC Power LED

 

Module Width

  • 1.5" standard, 2" with options
  • some left and right wing configurations are available

 

Power Consumption (aprox)

8 - 12 mA

 

Base Configurations

Part # Description List Price
MOD-FUZZMACH Fuzz Machine module  $235

 

Options

Part # Description List Price
MOPT-FUZZMACH-SPEC Early or Later Spec $0
MOPT-FUZZMACH-TRANSISTORS Transistors $0 - $TBD
MOPT-FUZZMACH-MIDS Switched Mids Control $19
MOPT-FUZZMACH-CLIP Clipping Switch $0 - $TBD
MOPT-FUZZMACH-BASS More Bass $0
MOPT-FUZZMACH-MNOISE More Noise $0
MOPT-FUZZMACH-LNOISE Less Noise $0
MOPT-FUZZMACH-CC Carbon Comp Resistors $10
MOPT-FUZZMACH-OD OD Switch $19