Buddy's Bass Fuzz Project - A Blended Dirt Box

BuddytheReow

BuddytheReow

Breadboard Baker
Hey All,

I recently dipped my toe into the wonderful world of BASS and so far I'm loving it. Since we are all DIY'ers here to some degree or another I thought I would document my journey to build a fuzz pedal specifically for Bass. I started this on a breadboard with a BLEND control between a Bazz Fuss and raw input signal. Although it worked I wanted the raw signal to be louder since the fuzz overpowered everything before I got past 9 o'clock on the blend knob.

Oh! I should also mention I don't have a bass amp yet. Just using my regular 2x12 cab and keeping the volume relatively low. I know I need an amp and maybe I'll pull the trigger on that soon: nothing fancy or big. I am a bedroom player after all :cool:

The next step was to make the raw signal louder. Being the novice circuit designer that I am I decided to whip up an LPB-1 to boost the raw signal with 1uf in/out caps. Although the booster acted as it should I was having BLEND problems. I upped the blend pot all the way to 1m and was still getting bleedthough when the knob was at both extremes. That's when I opened up a troubleshooting forum here and got pointed in the right direction.

A Bleeding Blend Control on Bass

Hey Guys, Since I got my bass last week I wanted to put together a simple little circuit for it, and I'm currently in the breadboard phase. At first I wanted to do a Bazz Fuss with large in/out caps with a simple volume control. Then I realized it would sound better to allow some of the raw...
forum.pedalpcb.com forum.pedalpcb.com

Here were the requirements I wanted for this build:
-Make the input signal louder
-Add a fuzz circuit in parallel
-Have a BLEND knob to mix between the two. No signal bleed should happen at either extreme
-Unity volume for the two parallel circuits
-Little to no noise/oscillation

So, @phi1 suggested a JMK Panner circuit to act as my blender. It's nothing more than an input and output buffer with a PAN/BLEND control in an effects loop. This was a great idea to start out with.
1646752496815-png.23881

@Feral Feline made some good suggestions and gave me the ah-ha! moment: I need to design a BASS circuit, not a guitar circuit. The LPB-1 should be thrown out and he suggested the Mole/Hog's Foot circuit as the boost portion since it's specifically designed for bass. I'll put this one on the back burner for now if I need to come back to it.

For now, I've got a good idea what I want and will share the next step in my journey...
 
Moving along, I decided to whip up a schematic real quick before I even started breadboarding. The troubleshooting thread has a few people mentioning that a Bazz Fuss doesn't work very well and I want to hear it first before tweaking it. I've starred a few components that I'll tweak to get the sound that I want. For now, I'll use a 1uf input cap, up the 100k resistor in the feedback loop to act as my booster, and play around with the diode in the fuzz block to see what I like. It turns out i DO have 15k resistors in my inventory.

1646772026552.png
 
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some googling led to some opinions that the lpb-1 works just fine on bass, basically full range (though not totally transparent). From what I understand the hogs foot cuts a bunch of treble, even noticeable on bass maybe. May or may not be what you’re after.

If you haven’t yet, play around with the BF circuit without buffer so you can get a feel for what the difference is.
 
Took some time to breadboard this afternoon. Below are my thoughts. I'll consider this the Mk. I.
1646772252992.png

The input cap was upped to 1uf. Using one of my neat toys (thanks @fig ) I was able to quickly find a value to use in the feedback loop (that's the green board on the bottom.) I wound up on about 300k. I also put in a 470p cap in the feedback loop to help with any hiss.

Rather than explaining the layout I'll explain the trace. The red trace is my input signal that gets boosted via the feedback loop. The blue trace breaks off after the boost to go into the bazz fuss. Both of them meet back in the middle via the BLEND knob and the combined green trace goes to the output buffer and then to output.
1646772727497.png

Some thoughts on this:

-Perhaps I need a tone control? I've only had my bass for less than a week and I can get some decent tones out of it with the active EQ so I'm not sure if this is really needed yet.
-I think I have unity volume/gain between the two circuits. I had to dump some signal to ground with a trimmer out of the fuzz block before going into the blend section.
-I think a gain control may be needed here in the fuzz section to dial it back a touch.
-The circuit in general is a little noisy. This could be from the breadboard itself or the circuit. Right now I have some hiss coming through. I hear it at the boost section and it's just amplified via the fuzz section. Maybe up that feedback cap needs to be tweaked or add some DC filtering from the power. Right now I've only got 100uf in the power rails.
-I still need to try the fuzz before the boost section to see if there's any difference sonically for me. Again, I'm told it doesn't work very well but right now i'm ok with it as is.
-I think a master volume knob should be added too.
 
fig said:
Looking good! Did you use 1uF between stages for a particular reason?
Click to expand...
I just want to keep the low frequencies in the circuit so I threw those in there. I probably should change some of them to electrolytics? We will see when I get some time later to tweak it.
 
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Digging around the interwebs has made me go deep down this rabbit hole really quickly. There are so many options for dirt, even for bass! A modded rat, a green russian, the Darkglass series, a bazz fuss, the possibilities astound me!

I want to explore other possibilities of what I can do to make a blended dirt pedal for bass. This video was extremely helpful in pointing me in the right direction. The green russian sounded really tasty on bass, but right now I've got my muffin factory and double muff that I play around with so that may be a future build. I did like the idea of separate wet/dry controls, but I think a simple blend knob is calling me.

I need to tell myself that there is no "perfect" effect for this project and to just pick something and stick with it as long as I'm relatively happy with it. Otherwise, I'll be in the breadboarding stage forever and never turn on a soldering iron.
 
BuddytheReow said:
Digging around the interwebs has made me go deep down this rabbit hole really quickly. There are so many options for dirt, even for bass! A modded rat, a green russian, the Darkglass series, a bazz fuss, the possibilities astound me!

I want to explore other possibilities of what I can do to make a blended dirt pedal for bass. This video was extremely helpful in pointing me in the right direction. The green russian sounded really tasty on bass, but right now I've got my muffin factory and double muff that I play around with so that may be a future build. I did like the idea of separate wet/dry controls, but I think a simple blend knob is calling me.

I need to tell myself that there is no "perfect" effect for this project and to just pick something and stick with it as long as I'm relatively happy with it. Otherwise, I'll be in the breadboarding stage forever and never turn on a soldering iron.
Click to expand...
Speak to jeffwhitfield, he says the Mastotron (Aloysius) is way better than the Mammoth (Snuffy) for Bass!
Both are available here at PedalPCB
 
Keep in mind any of these fuzz face based designs (mammoth, mastotron) are made to interact with your guitar/bass passive pickups, just like the Bazz fuss. OPs bass has active circuitry already. Not that cool sounds can’t be had, just be aware if you go one of these routes
 
I quite liked the Fuzzolo on bass as well, demoed one in store ages ago.

Need to build one, might even be one for the wishlist.
 
Only took a few minutes to fool around this morning. If I put the fuzz input before the input opamp I get bleeding in the BLEND knob. There is no difference sonically to my ears for the fuzz portion.

Oh, I also switched out the diode in the fuzz from a 1n270 to a yellow LED and it's more OD sounding which I like. I'm thinking Bazz Fuss will the way to go here with a diode selector switch and possible gain control.

I may have to scrap the opamp boost section or try it with a different chip. There is some hiss that comes through which I want to keep to a minimum. I've got a tl072 now and will try it with a 4558.
 
I thought we covered, in your situation it will make no difference fuzz before or after the buffer, once we clarified that your bass has active electronics. The fuzz circuit cannot interact with your bass passive pickups because functionally, it’s like there’s a buffer inside your bass. Once again, if you like the sound, go for it. But that’s why it didn’t sound different before or after the buffer.
 
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music6000 said:
Speak to jeffwhitfield, he says the Mastotron (Aloysius) is way better than the Mammoth (Snuffy) for Bass!
Both are available here at PedalPCB
Click to expand...
You see, I'm the other way on that. I gave my authentic mastotron away. Wooly clone has been on my board for over a decade.

I've been thinking about putting a wooly in a buffnblend with a bassweet (bassifrass) on the other side. Two of the most overwhelming bass fuzzes I've ever used.

Speaking on your mole/lbp1 thing, I thought a Mole WAS a modded lbp1. I haven't tried it but I've read you can dial back some cap values and get a sort of happy medium between the two. I love the mole as a utility, I slam fuzzes with it a lot, but it isn't my favorite sound on it's own. Pretty drastic wet blanket.

I also liked the sound/extra volume of my ocelot into a mole so I just made another and wired it in permanently. The volume pot on my ocelot is actually the mole.
 
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Had a few minutes this afternoon to tweak it a bit. First, I added a Baxandall tone stack after the blend and it really makes a difference, so I think I'll keep this one. I don't want a Muff stack since it will make is sound like a muff.

The hiss was a bit trickier to tackle. The fuzz amplifies whatever signal gets thrown at it, so it must be in the first opamp stage. I can do one of two things: a cap to ground before the opamp or put a cap in the feedback loop. I chose the later to start with. The higher the capacitance, the more treble gets cut and I think I'll live with a 560p in there. Anything over 1n starts taking too much treble out of the bass signal. The hiss is still there, but it's not as bad as having no cap in there.

1646856664907.png
 
The Mole has a couple extra caps to it and larger in/out caps compared to the LPB-1, other than that they are the same topology…





images

moleschem2.gif
 
Forum software is glitching on me again, couldn’t post the following in the message above…

I used 2u2 caps (largest box-films I have) instead of the stock 3u3 in my Mole, which is feeding the Buzz Box that I also subbed 2u2 to replace the stock 10uF caps there.

I liked the sound but there was little sustain and inconsistant, so last night I put in the stock 10u Tants in the Buzz Box and left 2u2 in the rest of the overall circuit — it smoothed out the sound, not better or worse, just different — and finally the sustain was there (and a lot more noise). Experiments will continue… I’ll try some parallel 2u2 box-film for 4u4 and 6u6 in the Buzzbox and see if that gives enough sustain with a little less noise.

There’s plenty of bass whatever values used thus far.
 
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My wife finally asked me what I'm working on with the breadboard and I told her for my new bass. "Are you for real right now? Didn't you just get your bass like a week ago? Shouldn't you just learn how to play it first before doing all your electronics crap on it?" My immediate response was "if you can play guitar then you can play bass" with the rationale that they both have strings and frets with one just being an octave down from the other.

Bass players please hold your cringe...

I listened to her and decided to just play for a few hours over the past few days. Learn some new grooves, some riffs, and focus on the fundamentals. I also plugged in my bass to all my pedals to find out what works and what doesn't work. My muffin factory works pretty good on bass after flipping a couple of switches so I may hold off on a green russian for a while. Some of the fuzzes work ok, but need just a bit more bottom end to it. My stock Rat doesn't cut it, nor my other overdrives since most of the bottom end is chopped off.

I've also realized that my amp is cranked too low and my pedals are cranked too high. This combination has tricked me into thinking I needed a boost pedal for this project to "match" the volume unity

I'm mentioning this because I think I need to take a step back from this project and maybe split it up into 2: a highly tweakable Bazz Fuss in a single box and a separate effects loop pedal to help put in some bottom end with BLEND controls. I think I'll be better off doing it this way.

Can anyone recommend a good effects loop DIY circuit out there? I've found one or two on tagboard that look promising.
 
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