BE: Fuzz Face with external bias control

I'm jotting down some notes for myself, because I don't expect anyone else to use this layout.  It's a little impractical in parts, but I had some spare board this size, and a pair of transistors that I liked on the breadboard that needed a home.  It's a progression on this somewhat more practical layout.   

If you're wondering what the BE part is about...  

BE FUZZ FACE V3 - EXTERNAL BIAS

Notes:  all links under the board.  Maybe reduce the 10k bias pot a little with a parallel resistor.  Cleans up well, solid fuzz.  Breadboard values: 1k / 6k8, maybe 5k6 at around 30 degrees.  10uf bypass cap, battery 8.5v

BE: Fuzz Face, SZ-3 (Sziklai pair)

Just one of my little side projects - it's a pretty hot day here, so not one for playing with germanium transistors in a big black box with a tin roof (also known as my garage / workshop).  The leakage goes nuts, and they sound like balls...  

While playing around with a bunch of old low-gain silicon transistors with moderate success, I remembered the Sziklai pair.   A minute later, and it was silicon fuzz heaven, so I had to come up with a layout to build one, hence the post.

BALMORAL ELECTRIC, SZ-3 FUZZ FACE

There are a few random values used that obviously aren't for everyone.  They just happen to be what's on my breadboard.   But hey, the post isn't for everyone; it's mainly for me to come back to later.

Transistor types are not listed, in part cause I can't recall what is on the breadboard.  They are all very low gain silicon transistors - I think about 50hfe or thereabouts.  I'll update the post with details later.

The Szik collector measured about 4.3v on a 9v supply.

SZIKLAI PAIR

What's a Sziklai pair?  It's a bit like a Darlington pair, but it uses an NPN and PNP transistor to create a single high-gain transistor out of the two low-gain devices.   They tend to act more like a single transistor than a Darlington does, which makes it handy for a fuzz face.

Before you get too excited, this works best with silicon; it's not a magic bullet for not so great germanium transistors, as leakage and noise are also multiplied.  

FURTHER READING

Small Bear has an article on Darlingtons and the Szik

WEM Project V / Ghost Warmjet - Modded Layout

 I have a fairly extensive post on the Wem Project V here, this is post is primarily to document my own work, as I'm not sure how many people would want to build in this style.  Standing resistors are mostly frowned upon in the world of vero, despite being commonplace on many vintage effects.   Joining two standing resistors in one hole is probably considered heresy. 

This is intended for a Hammond 1590XX size enclosure with 25mm pots.  The mods are mainly cap values, with a few minor changes to resistors, and an addition here and there.  

The bias pots can be very noisy in a few positions, and this thing will pick up radio (Shielded cable recommended).   Despite this, I still like the bias pots mounted externally, as they do add extra flavour to the fuzz.

MODDED WEM PROJECT V / GHOST WARMJET  -  VERO LAYOUT

Build progress shot - I've made two, one relatively stock (can use the same layout) and one with mods.  This one has the mods, and some temporary wires to test the bias before I box it up.

Hammond 1590XX enclosure - I may run with all chicken heads, although it doesn't leave much room for labels. 

FOXX: Tone Machine, BE Mods 2026

Updated Foxx Tone Machine layout on 0.15" vero.  This was inspired by the Aion mods - if you are unfamiliar with the Aion Vulcan, it's a Tone Machine with a modded EQ section (which is great) and an additional bypass option on one of the diodes - also a cool addition. 

I've tweaked a few values to suit my taste - this is not a stock Tone Machine.  

FOXX TONE MACHINE - BE 2026 V1

ADDITIONAL FOXX TONE MACHINE INFORMATION

Credit where credit is due - most of this information is from Aion build documents, which are excellent (go buy a kit, it will be easier than this...)

Transistors

The earlier Blue FTM used 2N3565 transistors with a hFE of around 230 to 245.   

The Red FTM used 2N3565 transistors with a hFE of around 450 - 550 

*I've also seen BC237B listed on the JD Sleep schematic from 2002.  

Treble Capacitor 

The earlier Blue used 3n3.   The Red used 2n7

Tone Control

Yes, it looks a bit like a Big Muff.   Can add a resistor after the treble cap to ground for BMP-like results.

The 4k7 resistor on the bass side of the treble control limits the range of the pot - jumper or remove for a tiny bit more range on the bass side.  

And of course, there is the mid-switch - basically adding more capacitance to the 3n3 treble cap, to boost mids.  I like a little bit of this action, but not too much.  15n is too much for me...  

Q3 bypass cap

Noted as 10uf on the schematic, measured at 22u, which does make a small difference to the bass response (more).  Basically, a 10u cap that is out of spec.

Additional Resistor

Red version had an extra 12k series resistor before the sustan pot, shaving a bit of level off.

Diodes

Use matched diodes in the octave section - originals used generic 1N34A diodes.  Matching just gives a better octave.   

Coupling Caps

Apart fromthe 100n on the input, the original used 10uf coupling caps.  They can be trimmed down to 1uf with no discernible difference.  

Optional Extras

The CBS Arbitier Doubler has a 10uf bypass cap on the emitter of Q1 - but is more gain here really needed?

Can add a 22u cap on the emitter of Q4 to bring the level up, as it can be a bit low.  

BALMORAL ELECTRIC: Kool Thing Distortion

This is an LM386L based distortion that I've been playing with - I called it Kool Thing as I was testing it on one of my guitars that has an open tuning (DADDAD for the record), and I was getting a distinct Sonic Youth vibe - which is not all that surprising with that tuning. 

It's basically a variation of a Spaceman booster up front, and the LM386L section is based on the data sheet, with some inspiration from the D*A*M Sonic Titan.  I did add a gain control to the 386 and have set this circuit up so it can run from clean to quite a lot of distortion, which is pretty cool.

I also tried the Q3 section of a MKIII style circuit after the amp to give it a bit more flavour - it was interesting but not worth the trouble.

It’s debatable that it actually needs two drive/gain related knobs, but I like the flavours you can get by combining the two.  If I had the drop one, I’d remove the gain control and just set the LM386L to full (cap jumpering pin 1 and 8).

I kept the value of the cap used in the tone control quite low to, as I don’t like tone controls that cut really heavily.  Even with a 2n2 this has plenty of roll-off.

It will sound different / not as good if you use an LM386N, for me, the LM386L is definitely better.

BALMORAL ELECTRIC: KOOL THING LM386L DISTORTION - VERO LAYOUT

 V2:  correction, had the LND upside down on V1

KOOL THING SCHEMATIC

ON THE SCOPE / FFT

CAUTION:  Start with device volume very low; these are 440hz sine waves that vary in level

 

Boost stage

 

Drive sweep, 0 to 100.  Gain 100

 

Gain sweep, 0 to 100.  Drive 100  

 

Drive sweep, 0 to 100.  Gain 50

Tone sweep, Drive & Gain 100

 

Clean Boost

ROLAND: BeeBaa AF-100, Point to Point and Vero Layout (Modded)

This is a bare-bones Roland BeeBaa.  I built the full version and found that all I really used was the scooped fuzz sound - so this is just that.  Nothing but unadulterated vintage Japanese fuzz....    

I think this works best with low-gain transistors.  I made a version using weird KT315 Soviet BCE transistors, and it sounds mean.   If you want to take the simplicity a step further, just drop the Sustain control and run at full tilt all the time - you'll have a one-knob Japanese fuzz.  

There are also two great variations on the BeeBaa over on Dirtbox Layouts, which are well worth a look. The Stoner Bee and the Pink Goat.  Genuinely great layouts there - check it out if you haven't found Ander's site before (which seems unlikely).  

ROLAND BEEBAA AF-100 - MODDED VERO LAYOUT

AKA The Balmoral Electric Bee

Version 2, which is slightly more sensible in terms of spacing.

Now, if you want to mod it even more;

• Decrease the input cap to 100n to reduce bass - or you could get creative and sweep or switch between two caps for a thin-to-fat setting

• Reduce the 4.7n caps to increase treble - 1n on Q3 as an example 

• Bypass the notch filter completely by taking a feed from the 1u cap on the output of Q3 - which will be insanely loud by the way

• Remove a 10u cap to reduce gain (Q1 or Q2)

• Adjust the notch to your liking - use values from a Univox Super Fuzz as an example

ROLAND BEEBAA AF-100 - MODDED POINT-TO-POINT LAYOUT

ON THE SCOPE / FFT

Input signal: 440hz sine wave, approx 130mv TRMS

KT315 Soviet-era transistors

A distinct octave effect can be seen, and there's a lot of high-frequency content.  

Note:  The version on the analyser below has a 1nf capacitor instead of a 4.7nf capacitor on the last transistor before the output, resulting in higher frequencies.

The stripped-back BeeBaa has a lot of output, and an additional tone control could easily be added before the volume pot.

As a reference, this is roughly the difference between a 4.7n cap and the 1n cap on Q3 in LTspice (1n = more high-frequency content, which I tend to prefer)

This is it on LTspice, which is pretty similar to the scope results - always nice when the match (the light blue one is the output, the others are straight out of Q1, Q2 and Q3)

BRIDGED-T NOTCH FILTER

This is the notch filter produced in the modded Roland Bee Baa.  As mentioned above, this includes the response of Q1, Q2 and Q3, and then the notch in light blue.

SOVIET BEEBAA

Modified Roland BeeBaa with KT315 Soviet-era transistors (note: 1nf on last transistor). This was built using a slightly different layout to the one posted above, as the Soviet transistors are BCE, instead of CBE.  

I probably should have cleaned the edges of the vero up a bit more...  this was something I threw together without breadboarding, so I wasn't sure exactly how it would sound.  In the end, I'm very happy with it - just wish it was a neater build, but hey..   

SOVIET BEEBAA VERO LAYOUT

ROLAND BEEBAA AF-100 SCHEMATIC  

The stripped-down version removes the following;

- boost section and switching

- one filter option

- tone control