Messages

Actually, I have one last question, pertaining to diodes...

In setting up a board for a switchable clipping diode option, I'm not sure the sizing needed for a few of them... e.g. a 4001 uses the same spacing as a resistor (I call it 4 hole spacing), while a 914 uses less (3 hole spacing).

While the following seem like they use 3-hole spacing based on internet photos, I don't want these standing up on the board... Anyone know the relative sizes for the following diodes:

- D9E
- 1N34A
- BAT41

As well, it seems like 914 and 4148 diodes have the same forward voltage and are used interchangeably at times... Does anyone know if there's an audible difference in sound for these?

Anyone know of a paul c fat bastard demo? I haven't been able to find one.

I have one on my breadboard now that is working - happy to throw something pretty rudimentary together. You playing through something more Fender-y or Marshall-y? Single coils or buckers? (I only have one guitar with buckers, and it drives both my amps automatically into overdrive since they're set for my single coils - I actually plan to use this pedal to tame that a bit, LOL). DM me if you're interested.

building it out in the next couple weeks if you'd rather wait for a build...

Here's a thread that works towards a transistor based approach towards a Rat.

https://www.diystompboxes.com/smfforum/index.php?topic=129355.40

Ha! It seems like they got something working, but are still trying to figure out some volume issues... I'll have to keep an eye on that. Again, the whole thing was just thinking of the transistor vs. op-amp muff and whether something like that would work for a RAT to get a little different flavor.

I like Jimilee's notion of creating something with a lot of clipping options. I was able to make a 1590B-sized single-sided PCB with board-mounted pot/switch placements. I based it on the Brian's schematic compared with the original schematic with the added (toggled) FatRat mods. Vol, Filter, Distortion, Fat (toggle), Clipping (1P8T rotary, 7 clipping + 1 no clipping. I did away with the Ruetz mod, I just don't use it and think the clipping options would be more flexible for me)... still need to get some of the more obscure parts, breadboard it, test it and etch it, but working toward solutions! hehe...

I also have to remember that the Slow Loris I have is 10+ years old now, and was the FIRST pedal I'd ever made. It has a lifted pad on the top layer (I guess the bottom pad is the one needed? lol) and isn't for the faint of heart when it comes to solder beauty. I looked at the schematic differences between Brian's now and the one I have, and there's a few parts he's taken out through the years that might explain some of the volume issues (an added 10k resistor, a pull down cap with the LED clipping diodes). When I look at Brian's schematic now compared to the original circuit, outside of the clipping options, it's effectively identical (a couple of power/biasing mods aside).

At any rate, I'll post the progress as I go along... As always, the madbean board proves it's the best for knowledge on this stuff! Thank you, all, once again!

super cool... always fun to look under the hood at these things from time to time - maybe I should try and get a can version of the 308 just to A/B test. Either way, this has been super helpful - thank you, all!

Before I start slicing and mixing schematics, I might start out trying to see what the different op-amps would do to the sound (op07, 741, 071, 301, 3130 - I read through this thread ( https://www.diystompboxes.com/smfforum/index.php?topic=127757.0 ) and am curious to see what it does), and for those ICs with external slew adjustment I might adjust the ceramic cap (which may cut off wanted, or accentuate unwanted, frequencies, but all in the name of science, right?).

I never use the ruetz mod - I'm not looking for subtlety when I use this pedal, lol - so I might do away with the sweep pot altogether in favor of something like jimilee's 8-way switch with the clipping options (might not fit into a 1590B this way, but maybe a 125b is possible? I mean, if the Runt can go into a 1590A... Might need to cut the number of options down, find a smaller rotary switch, or get creative with several toggles, but that's a "later" problem) and then use the FatRat schematic since it seems like those mods can be switched off, as well.

TO THE BREADBOARD!!! Well, after I order a few parts... Thanks, everyone! If anyone has more info, always open to it! :-)

Thanks, Jimilee! man, that looks like a fun pedal. I'll read that thread shortly... Are there particular clipping settings you prefer with that pedal? Is it, in fact, fatter/louder overall?

It's kinda fun to dig into this a bit... I had no idea RAT and subsequent clones/iterations had such lore. I'm intrigued by a darlington transistor (thank you, Bricksnbeatles), but have no idea where to start... if you or anyone knows, I'm game to breadboard something up!

I guess after looking at the data sheets (thank you BIO77), I'm still a bit intrigued at how the IC muff came about - from what I'm reading, it uses 3 gain stages using 2 ICs (as opposed to 4 gain stages using 4 transistors for the originals - someone correct me if that's not right). Fully realizing that the op-amp and original muffs do *not* sound the same (probably because the ICs produce more gain, BUT...), they still have a similar flavor.

I guess what I'm after isn't an exact RAT sound, but everything online that I'm finding is trying to mimic the lm308 or play with the clipping diodes (which I also want to do! hehe, but I'd love to go further).

Great stuff here - I'll do some sleuthing, but keep it coming if you have knowledge on it...

A big port of the Rat's character is it's pre-clipping EQ. It has a very distinct, aggresssive EQ going into the diodes. If you replicate that, it should sound similar. Most transistors won't anywhere near the amount of gain available as an opamp (even the crappy one the Rat uses), but that may not matter, depending on the clipping diodes you use.

Has anyone done this before? Is there a schematic floating around somewhere? Not that I know of.

The more I read, I'm finding most folks trying to find LM308 replacements because it's not made anymore - I have one or 2 extra of those, so that's not my goal necessarily... not knowing enough about these circuits, the gain is a mystery to me (and I'm sure far many before me have tried this route as 308s became hard to come by) - but maybe since the 308 is a single op-amp, there's a dual, or even triple NPN transistor combo that could approximate to the gain level?

That fat rat has a CMOS transistor. I have a Rat PCB with 8 different clipping options including CMOS transistors.

I'm not familiar with the fat rat schematic - do you have more info or a schematic to check out?

Also, thank you both for the replies so far. :-)

Okay, okay, okay - but hear me out... lol...

As I get my pedal board narrowed and finessed a bit (I've built over 3 dozen pedals at this point), I'm finding that of the muffs I've built, I prefer the 4 transistor versions (mudbunnies) over the op-amp versions (pig butt, and an actual EH big muff). Part of it is that Brian's docs encouraged experimentation and I was able to make something that sounded a bit fatter and louder than the IC ones with a bit more character...

Then I started looking at my slow loris - I have what I think is the 2012 version, which I had to dig for the documentation on - the new version has switching to different clipping diodes (mine is a board-mounted switch, no clipping center, LEDs up, diodes down - I almost always use the LEDs up). It's a great pedal, but can be finicky in the mix. I also built 2 Runts, but they don't have the same feel of the Slow Loris.

Then I thought: ya know - this uses an op-amp (lm308, I think?)... can one make a transistor version that might have different characteristics? So I went to the internet, and found more articles about how nobody knows the original circuits or conflicting information and blah blah blah... nothing specific enough for my question.

So I come to you, madbean forum, to see if anyone's tried it - I don't know enough about circuits to know where the op-amp sits in terms of affecting the character of the pedal, but in the spirit of experimentation, why not?

Any info is appreciated. :-)

Most EHX stuff in the 70s used board-mounted pots on single-layer boards and they're still going strong. With 6 pots, you've got enough anchor points that no one joint will be stressed, but out of precaution I would recommend soldering the PCB in place inside the enclosure if possible to ensure that it's custom-fit to the enclosure (to account for any slight misalignments in the drilling for instance). As long as you use good-quality copperclad then you'll almost certainly be fine.

Those are generally top mounted though, aren't they? Component side, I mean. I was taking about soldering them on the copper side actually.

Interestingly enough, I just looked at my stock of PCB material - and I have almost all double-sided board (copper on both sides). Debating if I should try a double-sided etch, but am nervous having never done it... I'm using press-n-peel blue transfer, which I've had success with in the past - I'm a designer by day, so I'm very familiar with registration marks. (I also have access to a cricut maker, but that feels... iffy. hehe).

If I did a double-sided board, do you think that's enough to hold everything in place?

Also, has anyone done a double-sided etch and lived to tell the tale? LOL...

You can do it but it can be a pain. The weight of the pots can lift the copper if you are not careful. My advice is design it for PCB mounted, but just used wired pots. That way, if you ever convert it to a manufactured double sided board later you're already perfectly set.

And, obviously do not try to do toggle switched PCB mounted.

Exactly the answer I needed and mostly expected. I have only board-mount pots, but can trim them and use the holes at the top for wires. No switches for any of the boards, so we're all good there. If I ever had boards for this one made, there would only be 5 connectors up top, so not complaining there, either. (but also not making boards later, hehe)

Thanks for the advice! :-)

Hi everyone!

I'm etching a few boards as I gear up to finally finish a pretty complex ardiuno-based pedal switcher I've been working on forever - I'm rusty, so need the practice.

One of them is based on the DIYGP Rock Bottom EQ ( https://www.diyguitarpedals.com.au/shop/boms/Rock%20Bottom%20EQ.pdf ), which I based on their schematic. I bought 2 from them, but they ran out and I needed a 3rd - which actually works out because I can add a 6th EQ band with the unused op-amp circuit in the schematic. Its tight, adds more jumpers than I typically like, and a single knob on its own row for volume, but that's okay by me.

I used board-mounted pots for everything. But then wondered if that's a no-no with a single-sided etch. I can solder the pots on the same side without issue, but is the possibility of pulling up copper or breaking the signal paths something to worry about?

Any help is appreciated! Thank you all so much. :-)

Thank you mauman!

I'll check out those sites. The information about ratings and sizes is really helpful too! I did read somewhere that 5mm is common, but it's nice to have confirmation on that. I'll be ordering all the parts (and extras) today.

Cheers

Stomp box parts has been pretty great for the sundry parts I've needed recently (I ordered a lot from their predecessor company, Mammoth parts) and they haven't been out of a lot. Only downside is that you have to order more than you need sometimes, but it's all fairly low cost stuff, and it never hurts to have extra... They also have powder coated stomp boxes in varied colors, which I appreciate.

Just don't make the mistake that I made and order 600+ volt caps... 47n and higher at that tolerance are enormous and will not fit on your board! lol... look for box caps for anything in the nf or uf ranges (unless an electrolytic is needed, of course). ceramic is great for anything in the pf ranges. I try to get minimum 25v, but mauman is spot on that 50-60v is a good range to strive for.

I had a lot of fun with the mudbunny, which was my 2nd pedal build ever (I tested the waters with slow loris, which was a slightly simpler circuit) - subsequently, I actually bought several mudbunny boards and socketed one of them completely so I could test out different cap values, resistor values, clipping diodes, transistors... As mauman said, it's a good thing to get extra!

I built 2 violet rams heads and 2 triangles - but I used LEDs for clipping in the triangles, mixed up the 560pf(s) with 470pf(s) here and there, mixed BC550 and 2n5088s for the transistors, and it gave me louder and fuller fuzz (I can't remember the exact specs - but the gist is: EXPERIMENT!). Some of it comes down to your guitar or your amp, too... I use a guitar with single coils 95%+ of the time, but a buddy that uses mostly humbuckers seems to prefer a green Russian circuit - if you run your clean sound with a lot of bass or vice versa, that will affect things... again, it's really great to experiment and see what you like when you have something as flexible as this circuit.

Good luck - and welcome to your new obsession!

one of my songs doesn't use your standard C chord; it's more whatever this version of C is:

7
8
0
0
x
8

It's a C major 9th (CM9), or C major 7th suspended 2nd (technically more correct, though it's the same note names as CM9), or you could read it as a G/C (G with C in the bass).

Anyway, Fuzz or any heavy amount of distortion is going to be REALLY unhappy with the C and D notes in that chord (the open D string and the C on the 8th fret of the E) -- low frequencies tend to have trouble that close together even on clean sounds, usually the solution is to use the 9th instead of the 2nd, so for a Csus2 versus Cadd9, something like x32030 tends to sound cleaner than x30010. This is an arrangement/physics problem, not necessarily an issue with which distortion pedal you decide to use. The way I'd handle it is to use the interesting 4-note chord in the clean parts and power chords in the distorted part unless you WANT the extra dissonance from the distortion -- people use power chords with distortion for a reason.

Swapping the transistors you're using in the boost isn't going to change it very much. I'd actually highly recommend sticking an EQ pedal after your fuzz and figuring out if any tone shaping will work better. You can then either just use the EQ pedal if it's complicated or make a boost with a tone control in the right spot if it's just a matter of cutting some highs.

I've thought of the EQ route, but maybe this is the nudge to pursue it - no clue if there's one I can build or if it's worth getting a MXR or something on the less expensive side. Might look into it...

I'm not opposed to a bit of dissonance - it's why I'm always looking for odd chords or alternate versions of standard ones - but you're spot on: for recording, I can do clean/OD with the weird chords, fuzz with the power chord versions... but I like to experiment - hoping the right mix comes along.

I played around a bit more with my 2-amp set up - one issue is that the JTM45 is so Bass heavy and I never realized it until I bought the Allen - put a MBP cherry bomb that has bass/treble controls in front of a mudbunny, which helped a lot with that, and moved a slow loris into that pedal chain and amp, which works for more articulate parts (even if a bit crunchier)

On the Allen (deluxe reverb), the bright switch was very shrill initially, so I tried it again after setting the bass and raw control up a bit, and then threw a MBP egghead in front of a mudbunny with clean blend on it. Pulled back the sustain, and put the clean blend about 55% clean 45% mudbunny. (I think the JMK clean blend always has some clean in the mix, but it's working pretty good). I'm getting close, but still find volume discrepancies, mostly with the slow loris.

Might look into the EQ route for the mudbunnies on the JTM and see if the 201s in the husky boy work well with the slow loris.

More experimentation to follow... Keep the suggestions coming, folks! :-) And thank you, midwayfair!

5457s are part of the problem, I would start there for simplicity. I'm not quite understanding what you're looking for in the end. Sounds like you want a fuzz but not.

The rat is too quiet? Can you expand a little bit, are you talking not loud enough?

Hi Jimilee!

I'm on the waitlist for 201s from pedalPCB (the PCB mounted version is more my speed, hehe)... "fuzz but not" is somewhere in the ballpark, but I'll try and give more context... I love the fuzz tones I get, but as an example - one of my songs doesn't use your standard C chord; it's more whatever this version of C is:

7
8
0
0
x
8

(can you tell music theory isn't my first language? hehe) - A standard C chord through any of these muffs can sound amazing (cherub rock is a great example - at least how BC plays in the music video, it seems they move from power chords to standard ones for the chorus), but my version of C gets really murky and unsettled in a bad way - too many notes, too little clarity. When I'm recording, I can record a clean track over my version and get it to sound good, but worry about live playing a bit.

Also, when I go from clean to fuzz, I get a notable volume drop - especially with the slow loris and pig butt. I read and thought if I could get a volume boost into the amp, it could solve potentially one of my issues, and having a treble/bass on the boost circuit might be able to get me some extra high-end from the muff - which is how I landed at husky boy.

All in all, I'm not writing for the big muff / fuzz sound of the pumpkins or silversun pickups or stoner metal - but I want to incorporate fuzz into what I'm doing, so it's a balancing act. Trying to figure it out, welcoming any advice. :-)

Let me know if I can clear things up more... And thanks for the reply so far. :-)

Hi everyone!

Noting that I'm using all madbean stuff out of the gate... Been trying to figure out a boost scenario with my big muff (e.g. pig butt and mudbunny) pedals - I have 3 versions: pig butt (the quietest of them), mudbunny (modded with bc550 and a mid pot) and another mudbunny (modded with mid pot and JMK clean blend). They have all the usual trappings: not enough clarity, loses notes in chords, etc., and I LOVE that sound, but am just not writing for that sound - wanting fuzz, wanting some note clarity, trying to work with what I've got.

I've tried running several overdrives in front of em, overdrives after em, amp tweaks left and right (I have both an Allen accomplice (deluxe reverb) and a mojotone jtm45 clone, and my overdrives are the green bean (ts9), egghead (clark gainster), cherry bomb (coloursound overdriver)).

As such, I've been tapping into my rats (e.g. slow loris) which can sound amazing, but also a bit quiet. I also have a mudbunny with a jmk clean blend circuit, so trying to play with that a bit, but again - too quiet.

I breadboarded up a husky boy to test it out, but only had 2n5457s on-hand (from what I've read, it's essentially a lower gain j201)... that circuit definitely helps with the volume, but also colors the fuzz tone into something more gritty than I'm wanting (running the fuzz into the boost to get the volume bump) and not letting me control the tone using the muff much. Wondering if the 5457s are the culprit, or if that's just how a boost will behave with a fuzz.

Open to suggestions, easily impressionable, and have lots of parts on-hand, hehe... Let me know if you have any suggestions, and as always, thank you in advance!

Congrats!  If it works, it's right, I always say.  Keep 'em coming!

Nice build!

I remember ordering >100V caps still have a few of them too. I remember thinking, dang these cost a lot per piece.

Thanks jessenator and mauman! It's definitely working great and records well, so I can't complain at all - and I *will* get rid of all those large caps - I don't care what it takes, lol! My hippie brain won't let me waste them, but I need the space in my components "jewelry case." Beauty be damned!

I use a jazz bass setup (housed in a non-reverse tbird body) and have it set for a little bit of grit. When combined with the direct out, it gives a nice tone that works great with my fuzzed out guitars but holds its own well, and also works great with straight and overdrive guitar sounds. For the songs that need bass distortion, I have a Bass BB clone that I etched some years ago that works perfect with it (Just put it before the sludgehammer and it's awesome. So the sludgehammer will take other pedals well, too!)

Again - recommended!!!