Buddy's Breadboard and Circuit Design Notes

Alright. Here's version 3 of the Spooky Dookie.

R3 changed to 68k. Diodes swapped out to 1n4148 (standard). BITE control changed to a C20k (100k was too much and I didn't have a 50) and acting as a voltage divider which can dial out the clipping. Once you dial the diodes out the volume goes up quite a bit, but that can be tamed. VOLUME upped to A250k. Thanks for looking out @Chuck D. Bones

I think this may be called done since I don't think there's much more I can do unless someone wants a go at it. It gets loud (booster), a bass and treble control, and clipping control for just a 1 transistor circuit. It's been sitting on my breadboard for a week, but I haven't had much time playing though it (maybe 10-15 min). This was a cool little project to put together some little circuit Legos. Maybe someone will make a PCB for this some day. I may commit this to vero or I may not. I've got a lot of house projects right now, so this is on the back burner for a bit.

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In the end of the circuit when everything is gettin' kinda dirty
I dial you up and ask you for more gain to see if it gets gritty
First, you're not SHO, LPB-1 with clipping diodes and "BITE"
and then there's "CUT" that keeps things tight

Boost is kinda crazy with a Spooky little Dookie like you


 
Another breadboard project finished up here. I've had this one on the side while working on the Spooky Dookie.

I posted a Fuzz Face tutorial recently. It's a pure breadboarding tutorial rather than circuit analysis. For such a simple circuit, it is deceptively complex in how everything works together. The good news is that pretty much everything on a FF is tweakable. If you want to see that here's the link.

TUTORIAL - Fuzz Face and a Request From All of You

The Fuzz Face. One of the first and most iconic fuzz circuits around. It is debatable whether there are more iterations of this classic circuit or the Big Muff Pi out there, so I'll let you be the judge. For any breadboarder or pedal creator out there, the Fuzz Face is almost a rite of passage...
forum.pedalpcb.com forum.pedalpcb.com

Anyways, what I put on the breadboard is the DAM Meathead dark version. It's dark because there are 2 filter caps in Q1 and Q2 that get rid of the highs. The stock version works pretty well on bass. On guitar not so much simply because too many highs are taken off. So, what I wanted to was reach a happy medium where it COULD work on both. I think I've found it.

Ho hum. YAFF (yet another fuzz face). TL/DR. Thank you, next.

But wait! There's more!

I have a pedal I already cooked up that I needed to replace one of the circuits with. 2 one knob fuzzes in one box. One of them has my NUT FUZZ. The other one is a Phantom Octave fuzz which uses a LM386 and found the stipboard layout via Tagboard. I wasn't 100% thrilled with the latter and this has been sitting on my bench for nearly a year.

The Ritual

Update: See post #2 with cleaned up gut shot and other circuit inside. Here's another BtR original. These are 2 one knob fuzzes that I made switchable in a single enclosure: a NUT FUZZ (my design) and Phantom Octave Fuzz. Both are stripboard builds. Both of these builds use a LED: one a red and...
forum.pedalpcb.com forum.pedalpcb.com

So, I've got a tweaked fuzz face to my liking, but I want it to have the "magic eye" where a LED lights up only when I play to complete this build. Our local circuit wizard Mr. @Chuck D. Bones was kind enough to point me in the right direction. To do this you'll need another transistor and a few parts. The unlabelled bjt would be Q2 in a FF. R2 below sets the maximum brightness. R3 sets the minimum brightness. If you change the bias of a "stock" FF, you'll need to tweak R2 and R3 accordingly. For Q1 below I just threw in a BC549c and she works!!!

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So, the full schematic would look like this. C2 and C6 here are optional and not true to the original FF. It may make more sense to up the volume pot value, but this will work.
1697551945931.png

Here's the stripboard layout with the "magic eye." I haven't built it yet, but it looks ok to me. With my tweaked cap values and magic eye, I felt that this is no longer a "true" DAM Meathead. As an homage, I've felt the need to christen this circuit the "Butthead Fuzz".

Edit: This layout has been verified and works perfectly!

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Sometimes when you go down a rabbit hole things can escalate really fast. I've been having some shower thoughts recently and decided to start acting on them.

EQ Before and After a Circuit?

I had a shower thought and wanted to bounce it off you guys if it's even worth pursuing. Regardless I'll breadboard something to find out for my own. Take a one knob fuzz for example (i.e Two Sticks of Derm) and build it stock. Putting a boost in front of it will produce a different sound...
forum.pedalpcb.com forum.pedalpcb.com

A decent EQ as recommended by our local circuit wizard Chuck is the TC Integrated Preamp (PPCB Integral Preamp). Breadboarding this was a bit of a pain since the charge pump itself took up almost half my breadboard! But, the good news is that the charge pump provides plenty of headroom for the overall circuit (I measured 32V on mine). I didn't have any PCB C-Taper pots so I had to solder some spare wire on it. No biggie.

Edit: I removed Q1 and all it's components. If you search around this forum you'll see that it serves no purpose and was residual in the design phase. Compare this one to the Isosceles Boost and you'll see what I mean. Is it possible Q1 and it's components do something? Sure, but I don't have a simulation to confirm anything.

My overall impression of the Integrated Preamp is positive. With a Treble, Bass, and Volume control it can get a lot done in terms of tone shaping. Is it perfect? No. A 6 Band EQ could do a better tone shaping job for fine tuning. This is pretty good though from a broad strokes perspective. I do want to try some 1 knobbers in front of this before committing to a bigger project and enclosure.

My last project was still sitting on my Buddyboard: Chuck's version of my SHO 'Yo Muff and was a good candidate to confirm the EQ was working correctly.

Breadboarding can get veeeeeeerrry messy very quickly. If you're making a stock circuit, no problem. But, if you're a tweaker you may get tripped up which part to swap out.
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I do like the Varioboost and have one on my pedalboard at the moment. Also an excellent tone shaper, but works different. Same number of knobs, though. The project I have in mind is to select a 1-knob circuit then have that go through a tone shaper. So far I'm not against the Integrated Preamp.
 
I could. The full idea that I have is a booster (treble or bass) into a 1 knobber (possibly 2 knobber like a Dist+ or OD) [4 selectable circuits] into another tone shaper. The boost and tone shaper would be selectable with a stomp switch. This would all go most likely into a 1590D
 
2 and a half months since my last post on here. The previous breadboard post was inspired by a summer project I've had in mind (I'll post in the build reports once fully done. Stay tuned). Anyways, I've got a small section in an enclosure that needs one more circuit. I've got one hole drilled for a pot and space to put another one in if needed. There is a booster (Integral Preamp) before this section so this needs to react well to a boost. My original thought is to make a 1 or 2 knob muff (tone section removed entirely). That requires a lot more components than I'd like, so I thought I'd start with something stupid simple: an Acapulco Gold (El Sol). The circuit itself works just fine, but doesn't play nicely with a hard boost in front of it. It almost sounds like gating similar to BJTs when they go in and out of the saturation point. It also sounds similar to another circuit I already have wired up (forgive me being too cryptic for now.) Oh well. It only took a few minutes to put this together.

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So, spoiler alert, my project is a dirt box (surprise, surprise) with a booster/tone shaper beforehand. So, Booster/EQ into a selectable dirt circuit. Right now I've got a Mach 1, a Dist+ inspired circuit, and a 2 sticks of Derm. My missing circuit I'm leaning toward Muff style since it has a more unique clipping sound. That, or I throw another fuzz in there.

I'm not sure what use the SHO would have here other than integrated into a circuit, such as my SHO Yo Muff from a few months ago.
 
It's easier to help when you provide all of the information.

Lightspeed: soft clipper
Dist+: hard clipper
2SoD: something splatty

How about you try a singe BMP stage with LEDs for clipping? If that doesn't make enough compression, then add another stage.

What made you choose the 2SoD rather than a Tonebender Mk III?

Are you using the charge pump with the Integral?
 
Yes, the Integral is built pretty much stock.

I chose 2SoD simply because I've built it before and I know the PCB is very compact. Never tried any of the tonebenders. Next project perhaps...

I'm not against a single BMP, but I don't want it as a standalone. The signal dies pretty quickly, which is why the 1st stage of a Muff is a booster. I'd like the Integral to add value to the circuit rather be a necessity.

Over the weekend I tried out the El Sol and was disappointed with how the 386 reacts with a boost. So, I tried over half a muff. This is built to a hybrid Civil War/Green Russian specs (they're similar but not identical). I have a switch on there (slider in the bottom middle) to allow either 1 or 2 clipping stages. Diodes are stock 4148s. While I like the sound of a second stage thrown in there, I do notice volume drop. I don't think there's a loose breadboard connection, so I'm assuming I'll need to put in a recovery stage when I get the time soon. Then I have the real estate issue inside my enclosure. I don't think I could fit a 4 transistor stripboard build in there nicely. Thinking out loud I can try 1 of 2 things: either swap the 1st and 4th stages with inverting opamps or take a stab at the Cream Pie fuzz (Frantone Cream Puff which is basically an opamp based Muff), but doesn't sound quite the same as BJT version.


1719257543883.png
 
It's normal for the output of the BMP's 2nd distortion stage to be lower volume than the 1st distortion stage because the 2nd stage compresses more. You can overcome the volume drop with a gain stage after the 2nd distortion stage or you can stack 1N4148s in the 2nd distortion stage to get a bigger clipped signal. Using LEDs in the 2nd stage will accomplish the same thing. You won't need the BMP's booster 1st stage because the Intergral already does that and more.

From an engineering viewpoint, it is a bad idea to run the first stages (Integral) on a high rail voltage then the subsequent stages. You can damage the OPA2134 by hitting the inputs too hard. Same goes for the Dist + opamp and the transistors in the 2SoD. Sure, it might work for a while, but don't be surprised if things start malfunctioning. You can use the Integral's volume control to reduce the signal back to safe levels, but it begs the question "why make the signal so big if the next thing you're going to do is cut it way down?" You could save some parts and run the integral on 9V. You don't need Q1 or Q2 in the Integral, they don't do shit. Those transistors made sense in the original TC Electronics Integrated Preamp, but the Integral is NOT the original TCE Integrated Preamp. Really, all you need from the Integral is the opamp and the tone network. The high rail voltage is useful if you want to drive the input of a tube amp with 20Vp-p. Driving a Lightspeed with 20Vp-p is just silly and if you asked Greer if it's a good idea to do that, I'll wager that they say "NO!"
 
@Chuck D. Bones you probably saved me a giant headache down the road! Yes, everything works fine for now, but I didn't know slamming such a big signal into a subsequent circuit could damage it over time!

Edit: I'm planning on putting in relay bypass instead of the standard stomp switch, so I'll have to take the board out anyways.

Now, in your opinion, what would I need to do to run this on 9V? I'm including the schematic below for reference. I'm assuming I'd have to take out the charge pump,C102-C107, and D101-D106. Then jumper from pin8 of the pump to where VCC/C107 meet? Would I also need to alter R4? Just spitballing here.

1719260269895.png
 
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That's right, remove those parts. Jumper from D101-A to D106-K. Jumper R102. Change R101 & R103 to 100K. Change R4 to 1M. Remove R2, R5, D1, D2, Q1 & Q2. Jumper Q1-B to Q1-C. Jumper Q2-E to Q2-C. Disconnect IC1-3 from Vref. Jumper Q2-B to IC1-3. Check your work and make sure all of the jumpers are in the right place.

Q2 was originally used as a low-noise 1st stage for IC1. IC1 was originally a 741 and needed Q2. Now that IC1 is a TL071, Q2 is completely unnecessary.
 
So, here's where I stand with my BMP inspired circuit. Nothing fancy, but it gets the job done. The input section acts as the recovery stage and the tone control is removed entirely. C8 might get taken out entirely since it's not really needed.

I call it "Muff Enough". A bare bones muff circuit that responds very well to a booster and tone shaper.

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