The Fuzz Ride - a tribute to the Fuzz Rite©  
A Fuzz Rite implementation with vintage sound but modern attributes
last update: May 14, 2011

Copyright 2010-20 by H. Gragger. All Rights Reserved. All information provided herein is destined for educational and D.I.Y. purposes only. Commercial re-sale, distribution or usage of artwork without explicit written permission of the author is strictly prohibited.The original units  with their associated  trade-names are subject to the copyright of the individual copyright owner. The Author is by no means affiliated with any of those companies. References to trade names are made for educational purposes only.By reading the information provided here you agree to the Terms of Use.
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Index


A Typical 60ies Fuzz
A Look At The Innards
Eliminating The Flaws
Adding Voltage Sag
Sound Samples




the fuzz rides again!
The Fuzz Ride in all its beauty (click to enlarge).

This is my implementation of a Green Bomb fuzz described by RnFR.
The hardware has been ordered from Musikding in Germany, box is of type BB. This seems to be a Hammond look-a-like.
The front plate is made of an image transferred to a thin aluminum sheet via photographical process using Copyphot (TM) technology. It is very resistant against abrasion. Unfortunately multi-color is rather cumbersome.

For the LED I used a bezel with lens, reminiscent of old tube amp jewel lamps.
There is a dying battery emulator switch to the side, which is not clearly seen on the photo. It can be actuated during performance, since it is loudness compensated.  The optics are strongly modeled after the original. Why improve an already good design?



A Typical 60ies Fuzz

The Fuzz Rite is a fuzz box whose tone would be called typical 60ies – raw and fuzzy. It is similar in construction to other contestants of the time in so far that the available semiconductor devices at the time were low gain compared to contemporary devices and circuit designers would try to wring the most performance out of those transistors with appropriate circuitry. It thus has an input stage similar to the then ubiquitous fuzz face and a relatively high output impedance, meaning  one may encounter severe problems trying to interconnect the device with other devices just like with a fuzz face.

People have made extensions to the Fuzz Rite, mainly Gus with his Rite Fuzz and a designer called RnFR with his Green Bomb. Also, there is a plethora of fuzzes that use a similar topology, as shown on the fuzz comparison chart on Aron Nelson´s page.

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A Look At The Innards

One of the measures to exploit gain is the grounded emitter. Since in a common transistor voltage amplifier stage the gain is mainly set by the ratio of the collector resistor versus the emitter resistor, a grounded emitter will yield the most gain within margins. This also will limit the available headroom, which is why the Fuzz Rite can sound very gated at some settings. From a viewpoint of fidelity, a bad thing, from a musicians viewpoint, maybe a good thing. As usual, the beauty lies in the ear of the listener.

Also, this may not work equal with all transistors, so a first improvement is to include small value emitter resistors. Also, the original had the low band pretty much restricted (a sound which must have been favored in the sixties), so the Gus Rite and Green Bomb use much bigger capacitors for extended bass.

Of course, this changes the tone away from the original. A designer and forum member called RnFR has added a control that lets you sweep everything from stock grounded emitter (for the first stage at least) to a phase cancellation tone similar to the original on the other side in his Green Bomb circuit. This trick is not far from genius.

One of the drawbacks of the input transistor stage used is the very small input impedance, similar to a fuzz face. There are only a few kOhms one could expect. Like in a fuzz face, this leads to a radical cleanup action when the guitar´s volume is turned down, subjectively even more dramatic than with a fuzz face, almost like a on-off switch. Well, it turned out some people like that, but an impedance mismatch is always prone to invite trouble with preceding and succeeding devices.
Impedance needs to be matched properly, so this case calls for buffering.

Also, the „fuzz“ control in a Fuzz Rite architecture differs significantly from other fuzz box topologies in that it does not change the amount of signal that hits a subsequent stage (like in a classical tube amp). Most contemporary fuzz boxes have an „amp-style“ gain control that sets the amount of signal going into the device and an output volume control to compensate the volume increase, while the overall gain is usually kept unity. The guitar´s volume and the fuzz control are somehow interacting (one of those fuzz boxes is the Boss Tone).

The Fuzz Rite architecture
does of course provide some fuzz adjustment, but it rather blends the signals coming from two amplification stages, the one in front and one that is daisy-chained to the first (out of phase), and with a volume increase towards second stage settings. This architecture leads to a wide range of tonal possibilities from very gated over octave effects to fully nasty distortion, which other fuzz boxes cannot produce. Very versatile, if one likes the basic tone.

But it stems from the very same topology, that the guitar´s volume control is the only way of changing the amount of signal that hits the first gain stage. It is therefore of prime importance, to have a good working volume control, one with more than an on-off-action. The (input) buffer does away with that problem, without changing the overall tone.  The theory behind that has been explained at length in
my Poker Face article.

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Eliminating The Flaws

So, yes, the Fuzz Rite is a good design. But it can be augmented.

block diagram
Block diagram  (click for details).

I did initially not consider my augmentations a "circuit" worth drawing, but for the sake of clarity and due to popular demand I have added a block diagram.

The internals are documented elsewhere at length anyway.





I buffered the thing, as I have layed it out in my Poker Face article.

What was called the „fuller mod“ on a fuzz face, namely a series resistance that creates some sort of current drive on the input, also works on the given topology. One may indeed want to make this variable, but I decided to make it fixed. Too many knobs. I chose a 5k resistor in series, which does not drop the voltage significantly and simulates the impedance of a single coil drive. The tone remains unchanged by this measure, as A/B comparison shows.

Also, a 250k Pot on the output is not exactly low-impedance, so the output got buffered as well. The output buffer will eliminate tone-sucking due to long cables and drive problems possibly caused by subsequent devices and does not contribute significantly to battery current consumption.

The "on"-LED by the way is comprised of the usual ultra high efficiency LED out of a defunct head-lamp in combination with a 15k series resistor for ultra-low current demands one could only have dreamt of just a few years ago. A lens bezel helps to disperse the somewhat pointed beam.

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Adding Voltage Sag

If misbiasing makes happy, one might as well try to drop the supply voltage to encourage this even more.
Interestingly, the tone does not get more gated or farty by dropping the supply, it gets milder - the gain drops! I settled for a resistor of  18 kOhms in series with the battery.

Since switching between full/sag power invariably produces a volume step, this needs to be compensated. I installed a 820
kOhm resistor in series with the volume pot (on the "hot" side) that gets bridged when the sag resistor is in place via a DPDT toggle switch. You may need to play with that probably. The overall volume is of course reduced by this measure, but for my taste there is still enough reserve. If someone wants the full volume, play with the balance of those two resistors or simply don´t implement this mod at all.

Listen to the sound samples and determine for yourself, if this is worth the extra effort. (coming soon...)

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Sound Samples

A few basic sound samples can be found in the stompbox gallery.

The subsequent recordings have been done using the following setup:
  • Strat modified according to specs, neck pickup
  • J-FET buffer directly after the guitar except where noted
  • 59´ Bassman emulation (slightly turned up gain) with 4x10 Bassman Speaker emulation (Digitech RP-500), with EMT Plate reverb
  • PC hard disk recording over a Turtle Beach Santa Cruz sound card.
(Names may be copyrighted by the associated copyright holder)

Note that I have made recordings with full and reduced guitar volume to see how the pedal cleans up. It does indeed, particularly with the reduced supply voltage. Also note the change in character with different shape and depth settings.
The noise you may hear in silent passages comes from the single coils, not the pedal.



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Update History
  • Nov 4, 2010: corrected some subtle factual errors and added block diagram due to popular demand, added specific sound samples
  • Nov 3, 2010: sound samples
  • Oct. 24, 2010: first release
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