SuperFuzz Tone...wheres the bass?

[Canucker]

First off! Hey guys I'm back! I haven't built a pedal in about 2 years....now that winter is over I here I can etch some boards again!

but before I do that I checked out one of my old unfinished builds... The Univox Superfuzz. I finished up the offboard wiring and plugged it in and worked right off the bat! What was I waiting for?....problem is ITS ALL TREBLE!!!!!! I know its a harsh fuzz...but until you turn down the treble (9 oclock) and turn up the bass (3 oclock) on the amp and go all bass on the tone knob of the guitar its just to trebly....and you stomp on the pedal to go back to clean and you are left with an unusable tone (tried it on more then one amp).......

....sooo would you advise I add a simple tone circuit....or is there a cap here or there that I should swap.....

I used the design from Ustomp https://ustomp.com/projects/Unicord%20Super-Fuzz/superfuzzbuild.pdf

I recall once upon a time that the 3.3k resistor on the upper left should be omitted.... mine is still there....if left out should I leave a gap or connect the points without any resistance?

Thanks in advance for any advice! You guys rock!

[Canucker]

just to add..... at the input I did change the position order of the first cap and resistor....so 10uf Cap then 22k resitor....I remember that advice being all over the place for this one.

[rutabaga bob]

Too much treble at both settings of the tone switch?  It’s an old-school fuzz, for sure, but neither position is palatable?  Welcome back, by the way!

[Canucker]

cool fuzz, treble in any setting. I've watched a few demos of them and wanted to build one ever since I got mudhoneys first album so I'm familiar with what they should sound like.... I think I ended up building the most complex treble booster instead! Thanks for the welcome back!

[Sooner Boomer]

I couldn't find a schematic for the exact build you've got.  Ignorance is never an obstacle for commenting on the internet.  I did find something I think is close, a schematic from GGG's super fuzz kit: http://generalguitargadgets.com/pdf/ggg_superfuzz_sc.pdf

One of my old electronics instructors said the best way to troubleshoot is to divide and conquer, so here goes.

It looks like there are five basic parts to the schematic.

Q1 and Q2 form an input buffer, C2 and C5 do some tone shaping.

Q3, Q4, and Q5 are the "overdrive" section.

D1, D2 provide clipping/harmonics

C12, C13 and R24, bR25 for a tone stack (R36, R37 for a voltage divider to run "clean" sound around to the tone switch)

Q6 provides an output buffer.

If you're getting poor tone when the switch is in either position, the problem is *probably* upstream from the tone stack.  If you've got an audio probe, preferably a small amp you can listen to through headphones, I'd look at the wiper of the expander pot and see what the tone sounds like there.  Then listen again before and after the clipping diodes.

I'm making this all up.  If this has any bearing on reality, it's shear coincidence.  Good luck.

[Mark Hammer]

The problem, which you will face with any octave-up fuzz, not just the Superfuzz, is that everything is shifted up an octave, including the bass.  And because it is a fuzz, that means that not only is the bass end shifted up an octave, but there is more treble content coming out than going in.

One feasible solution is to play with the tone-filtering.  The stock circuit has a 2-position tone switch that selects between a heavily midscooped sound, and an unfiltered sound, with attenuation to match levels with the scoop sound.

The scoop filter has a 1000pf cap to pass the top end, and a 22k/100nf/10k network for the bass.  The 22k/100nf pair rolls off content above around 72hz, at 6db/octave.  I've seen some drawings where the 22k and 10 are reversed, yielding a rolloff starting at 159hz, which keeps more of the bass.  Personally, I prefer that.  You still get a scooped sound, but with more girth.

Another thing to play with is the top/bottom balance.  Unlike the Big Muff and many other pedals that provide a control for essentially panning between the top and bottom filter paths, the SF is fixed.  Consider inserting some resistance between that 1000pf cap and where it would normally join up with the content from the bass side.  That could be a 50k panel-mount control or an internal trimmer, configured as a variable resistor (i.e., two solder terminals not 3) to attenuate how much treble is mixed in with the bass.

[Canucker]

off to work right now but I will poke around with it this weekend. You guys around here amaze me every time. I have no formal training in this stuff.... I'm just good with my hands and usually know how to ask the right questions. I noticed when I refound the layout on ustomp that the link for the schematic just took you to the page you were already on...not a dead link but not a link to what it was suppose to take you to. Thanks again and again and again!

[duck_arse]

I'd put money [yours, not mine] on a wrong value, but until we see the photos of your board, we can't say which one.

[Mark Hammer]

The 3k3 resistor does not absolutely need to be there, but it is not a cause for any malfunction.  Indeed, connecting that end of the Expander pot directly to ground, rather than through the 3k3, would mean that if you turn the Expander control down too far, you would not hear anything at all, no matter how high up you set the Balance control.  The 3k3 simply ensures a minimum "push" to the octave doubling circuit.

[Canucker]

Good info on the 3.3K resistor.... I've read a few "take it out/ mine works fine with it" posts but never an explanation one way or the other.... I kind of suspected what you explained and its nice to have confirmation from someone who knows more then me (I often think you all do but I seem to get by pretty well!).

Starting the post got me off my ass and made me work on it because hey I owe it to you guys to do something if you are willing to offer guidance.

I got it functioning in a satisfactory manner tonight! by which I mean I can actually use it and will use it to make music now! though there is no octave happening but its a good fuzz now.

What ended up doing the trick was taking out the Germanium Diodes and putting in a pair of 1n4148 Diodes..... and presto it worked! Sadly it was so long ago that I ordered the Germanium ones I can't remember what they are, can't find the package they came in and looking up the order from smallbear in old emails just says "Diode NOS Germanium
(Diode NOS Germanium)" and they were $0.45 in 2013..... I don't know if I ordered them specific for a superfuzz or for a Green Ringer (which I did use them for also and it sounded like trash with the silicon I had in and the germanium made it as good as it gets I believe).

Thanks again for giving me the push I needed to dig in and get this figured out. Maybe some day I'll dig for the octave...not that I really need that function.

[Jubz]

Hi.

For the moment i would put money on a wrong value too. Stock the superfuzz is a bass monster. Listen to the sick bass tone of gratitude from the beastie boys. Superfuzz bass goodness going on here.

[Mark Hammer]

Good info on the 3.3K resistor.... I've read a few "take it out/ mine works fine with it" posts but never an explanation one way or the other.... I kind of suspected what you explained and its nice to have confirmation from someone who knows more then me (I often think you all do but I seem to get by pretty well!).

Starting the post got me off my ass and made me work on it because hey I owe it to you guys to do something if you are willing to offer guidance.

I got it functioning in a satisfactory manner tonight! by which I mean I can actually use it and will use it to make music now! though there is no octave happening but its a good fuzz now.

What ended up doing the trick was taking out the Germanium Diodes and putting in a pair of 1n4148 Diodes..... and presto it worked! Sadly it was so long ago that I ordered the Germanium ones I can't remember what they are, can't find the package they came in and looking up the order from smallbear in old emails just says "Diode NOS Germanium
(Diode NOS Germanium)" and they were $0.45 in 2013..... I don't know if I ordered them specific for a superfuzz or for a Green Ringer (which I did use them for also and it sounded like trash with the silicon I had in and the germanium made it as good as it gets I believe).

Thanks again for giving me the push I needed to dig in and get this figured out. Maybe some day I'll dig for the octave...not that I really need that function.

The Superfuzz circuit will work just fine without those diodes.  Seriously.  I even installed a toggle to switch between germanium, silicon, and no diodes, and it fuzzes just fine.  The diodes add a little bit of clipping but there is plenty without them.

So why are they there at all?  The octave tends to get lost and inaudible in the midst of all the additional harmonic content at the outset of the note.  The harmonic content, original as well as doubled, settles down after the string starts to decay, such that the octave seems to emerge or "bloom" as one sustains the string with finger vibrato.  Trouble is, all that is happening as the string volume is declining.  The diode pair creates the illusion of holding the volume constant, by limiting the maximum level.  It/they serve as a quick and dirty limiter.  That will be true with either germanium or silicon or Schottky, but the lower the forward voltage, the more constant the output level will seem to be - at the cost of output level - and the more obvious the octave will appear to be, as it blooms over time.

The Green Ringer is also an octave doubler, using a phase splitter, like the Superfuzz, but lacks the additional diode pair to ground.  Adding a diode pair, in tandem with a bit more gain at the front end of the circuit, dramatically improves the audible octaving.  Point made.

[Atodovax]

Try lowering the gain of your transistors! . That worked for me. I used 140hfe (aprox) and now is much more usble. I can send you a video if you want

[digi2t]

Try lowering the gain of your transistors! . That worked for me. I used 140hfe (aprox) and now is much more usble. I can send you a video if you want

AMEN!!

[Atodovax]

Try lowering the gain of your transistors! . That worked for me. I used 140hfe (aprox) and now is much more usble. I can send you a video if you want

AMEN!!

I Forgot to say that YOU recomended me this great advice