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If you BB it, try it with and without the .1uf ceramic in parallel as discussed earlier.
Out of curiosity, what is the circuit of the pedal you tried it in?
Also, I'd probably add CLRs on to the posted schematic then tune the RC to taste from there.
But add a single LMC555 to your next mouser/digi order before scrapping anything for good. I do think that would at least improve, if not fix it.

Not sure I have any .1u ceramics - plenty of box, and one giant film... not sure if it'll make a difference, but I'll try out what I've got. I didn't think it would make a difference which 555 timer chip I got (I'll be honest in that I figured it was just a brand thing with the letters, LOL - even after all these years, still such a noob).

The circuit is a mudbunny from 2012 or 2013. I had a feeling this could happen, honestly, but like I said: I like to experiment a touch - I think I had an issue with a delay or tremolo on a one-spot a while back that was powering my whole chain when the muff was on; the immediate fix there was a decoupling cap on whichever pedal that was at the power supply, and the longterm was moving from the one spot (I have a MXR thing now, which I like - the one spot plug cracked the last time I went to plug it in. No thanks). It was too long ago for me to recall exactly (I think it was possibly a modulator on a 1776 multiplex?), and I think I rebuilt the pedal later on into a new enclosure anyway.

Either way, noted on the lmc - next time I order, I'll see... I have 5 of these little boards, and 3 or 4 other pedal enclosures to update, so may as well use em!

Another alternative is instead of an astable vibrator, use it as a hysteric oscillator. See attached. Not sure if it would improve or not but easy enough to breadboard.
Noise is likely from the current spikes from the NE555 because, for a brief moment both transistor are high. I didn't even consider this 2hen I made the original recommendation. My apologies. This isn't the case with a CMOS 555(LMC555) and they're almost as cheap as NE555. About $1.50 each.  Or you can get 10 for about $4 on AliExpress. Tayda doesn't carry them unfortunately. They can't handle as much current as the NEs, but 2 LEDs would be fine.
You could always use your spare NE555s and make some Atari punk consoles. Or a stun gun... Then you'll really be down the rabbit hole.

It's no worry, man... I like to experiment with simple-on-the-surface stuff like this, hehe. I'll breadboard up what you posted and try it... Worst case scenario, it just has an extra LED and I give the timers to my circuit bending buddy. I'd be out a few bucks tops.

It's still looks fun with the jewel lens either way - my goal has always been to make them look like toys - fun color enclosures, LEDs and knobs, no labels (though I think I may hit up a buddy with a cricut soon for a couple of the more complicated ones).

Hey, you did it!
Try adding a .1uf ceramic cap parallel to the electro on the VCC pin.
You could also try a CMOS 555, as it won't have the current spikes of a ne555, but you'll likely need to tweak the RC filter some.

I'll give the cap in parallel a try - I disconnected the timer board entirely to try and breadboard a few scenarios - including decoupling caps, setting the power supply same as a standalone pedal (5817 > 100u > 100n) and nothing even phased the pulse, so for now I just threw a red LED into it, which is still kinda cool.

the 555 chips were cheap, and I ordered so many thinking I'd be using 2 in each circuit for a 3-way flash, but alas... I simplified to 2 colors, so I'll stick with what I have to not be wasteful... BUT, I have a 2nd identical pedal to modify, so I'll give this a shot in that one and retrofit this pedal if it works... more to follow for sure.

This pedal is cool - I modded a mudbunny in Mayo specs with some varied part replacements and a switchable mids pot, but it never fit right in the enclosure, so I took out the 25kb pot, I used a 50kb with a 100k resistor in parallel (don't care about the taper, honestly) to get to 33k on the dot (a 4k7 sits between lugs one and 2), which is the exact value for R18 - all the way down is stock, turn it and you've got mids control. This left yet another drill hole to fill, so I guess more LEDs equals more better, hehe...

Thanks for the help - if you (or anyone else) thinks of anything else, my eyes/ears are open. :-)

Hi everyone!

For my latest project, I'm converting an old enclosure that was drilled for a battery to one that has the foot switch down at the bottom. I retrofitted the old hole with a jewel lens and a 555 timer LED circuit with 2 LEDs flashing (think old pinball or carnival display).

https://youtube.com/shorts/k1Dx8S_cJPE?feature=share

The problem: I can hear the timer pulses in the audio signal.

My assumption is that possibly a cap at the power source might help (or maybe even at the ground), but I have no idea how to think of values and all that...

The timer circuit is below (I'll admit it's a bit sloppy - definitely would make changes next time, but trying to work with what I've got here) - 9v is directly to the power supply, ground is to the LED lug of the typical 3pdt foot switch.






I could always just throw a standard LED in there, but I'm trying to have a little fun here, hehe... each pin with any power has 100u cap on it, and the rest are 1k resistors (I have so many, so I just ran them in parallel to get the values I wanted).

Any thoughts?

Alright - I just did a little more experimenting...

If I take a 50kb pot, put a 100k resistor across lugs 1 and 3, then a 4k7 across lugs 1 and 2, I get about 3.7k on one side, and 32.7k on the other...

I feel like this is... ideal? Someone tell me the consequences of wanting it all, please... hehe.

Hi everyone!

I have 2 old mudbunnies that are to Mayo specs (ish) - I did the mids mod: 4k7 across lugs 1 and 2 of a 25kb pot with lugs 1 and 3 soldered to R18.

I was smart enough to put a toggle in so I could have the stock 33k on one side, the mids on the other. (most other specs for triangle/rams head/etc. are around 39k)

I'd like to get rid of the toggle, but be able to dial in somewhat near stock. This means a 50kb pot, I assume, but I need my math reviewed here:

The 25kb pot with 4k7 across lugs 1 and 2 gives me about 3.85 on one side, 21ish on the other.

If I do the same with a 50kb pot and around a 10k resistor across lugs 1 and 2, that would get me somewhere between 8.5 on one side and 42 on the other. stock is 33k.

Obviously, this would change the character of the mids pot, but I never turn it all the way down.

Can someone help me figure out how to do this right? LOL...

As always - thank you in advance!

There's no harm in running at 18v with a tantulum there since it is half supply. However, tants are expensive and should be saved for situations where they are needed. Electros cost next to nothing! Just my 2 cents.

Good advice! I think I'd used up all my 10u caps and didn't think I'd be making another order for a while at the time. I could always swap it out, but I'll cross that bridge if/when I get there.

Thank you for the reply, as always - this is the best forum!

Hi everyone!

I built a husky boy - but one of the 10uf caps (c10) was a tant cap with 16v rating (realized after the fact it was only 16v - I just wanted to use up my supply of tants).

When running on a 9v supply, I measured with a multimeter the voltage for that cap, which was around 4.2ish.

Would it be safe to run this on 18v given that particular cap is only running at half the volts, or is there something that happens on power-up or down or whatever that might make it risky?

Really, I just have (2) unused 18v outs on my MXR power supply, and I need an extra supply and there aren't any other pedals I can use on them, hehe...

Any help is appreciated! Thank you!

I built a few mudbunnies, which I think are the same circuit?

The rams head version is what stuck for me, but I tweaked the transistors to a mix of 2n5088 and bc550 (I think) and played with the ceramic cap values - also maybe red LEDs for diodes?

I also added a mids pot that could be toggled.

It's one of my first few pedals that I made and I still use to this day. (I have a couple tweaked triangles and op amp ones, but they never sound as good with my guitars and amps for some reason)

I basically socketed an entire board and then made all the versions I thought would sound good, then tweaked as needed and built the best ones. It's a really flexible circuit - so long story short: you might find similar success with another version.

Also: cool pedal!!! Never thought to footswitch only part of the circuit to make a 2 setting situation (perhaps this is a normal thing these days, I'd have no idea) - kinda brilliant! Nice work!

Inspired by the recent conversation I'd started about the possibility of an all-transistor RAT to get some different sounds, I went the route of a certain mr. Jimilee and made a RAT with 8 different clipping options on a rotary switch.






I call it the Chicago RAT! (But really, it's should be called the jimilee rat ripoff extravaganza - but that doesn't roll off the tongue quite right, hehe).

I'll make a video in the coming days of the varied sounds, but the clipping options are all pretty unique and there isn't one that I don't like. I never used the ruetz mod on the slow loris pedals I built long ago, so I didn't include that, but I did add the FAT switch, which is great for bridge pickups, but kinda muddy for neck. I feel like hum buckers would be straight mud with the fat setting.

Clippers are: 4148/bs170 - 4001/bat41/bat41 - red led/red led - 4001/4001 - 2n7000/2n7000 - 1n34a/1n34a - 4148/4148 - no clipping (op amp only).

The filter pot is reversed for me - not sure how that happened, but it might be that I'm just not that good at Eagle. It works, so I don't care what direction it goes.

I've had the enclosure drilled for another pedal like 10 years ago, but I rehoused that one - I just never found knobs that worked with this enclosure's color, but once I had some metallic gold knobs for another build, it became my mission to salvage this one (always thinking sustainably!). Filled the holes with JB weld, the did my best to re-drill. Not exact. But close enough.




The foot switch was originally drilled to fit a 9v battery, but I don't use those, so I got a jewel lens cover. I wanted to use a 555 timer to flash lights inside, but it's too tight in the enclosure, so I'll have to save that for other pedals I convert later. This just gets an added LED.

Pro-tip (or, well... greysun tip, lol): I had gotten solder lug pots when I thought I was etching this myself, so to convert them to board mounted, I just twisted some excess leads together - little solder, little trimming, and we're good to go.




I have one more to make... wish me luck!

I had to make a friend for this one... same thing, different color - this will go to my Marshall amp, while purple will go to my Allen. Or vice versa. Whatever color combo works best with the other pedals (that's what's most important, right?!).

Only weird thing with this one was the green LED - I typically use the madbean recommended 4.7k resistor, but these green LEDs I have are BRIGHT! Had to remove and replace the resistor with a 10k, and it still might be too bright, but at least is acceptable.

Note to newbies: individually test your LEDs with resistors (or connect to a 10kb or 25kb pot, find the brightness you like on each, measure the pot and write it down - you'll need a 500ohm or 1k resistor in series to ensure you don't accidentally blow your led by turning the pot all the way down). Getting that resistor out after everything was wired up wasn't fun in any way whatsoever.

This is where my brain went to when I saw the top side of your build. I love it.


I've been looking into EQs, possibly importing a (well-kept) GE-7 from Japan, or something else, but I'm liking this option, since it wouldn't require modifying an ancient Boss PCB. Well done!

Anything involving me that reminds folks of prince is a high HIGH compliment, heheh...

I was surprised that there weren't many options for building your own EQ - watching DIYs video about it, he explains his theories, which make sense... lots of options out there, the slider pots are hard to DIY, what would be unique about it... all made sense.

But, if you could customize the frequencies and don't care about using normal pots, there's lots of opportunities. Their documentation is excellent - gives the values needed for lots of frequencies and you choose the ones you want...

I used 100, 250, 750, 1.6k, 2.2k, and 6.6k. I think it's about 10db over and under for each frequency.

I could have socketed some to change them out later, but felt like I had a good range and am not afraid of commitment. Heheh.

Recommended build!

Next up - EQ!






I also designed this board, hoping to do a single sided etch, but wound up ordering from JLC. Being able to board mount all the pots made this a VERY easy build (aside from the LED - some of my past yellows are reversed pos/neg and I thought I'd used them all up... PITA!). You can still see all the jumper holes throughout the board, hehe. I wanted an EQ to add some frequencies to (or maybe better manage?) my big muff (mudbunny), and I think this will work great.

This was based on the schematic from the EXCELLENT DIY guitar pedals "Rock Bottom 5-band EQ" project. I ordered 2 of their boards (if anyone wants to buy one, I've got 2, hehe), but after they shipped noticed that one of the op-amps wasn't used - and one thing led to another while I had covid, so I wound up creating a 6-band EQ plus volume and I do not regret it - but I also would never do it again, hehe. Order theirs - it's a cleaner design, and will fit in a 1590b

This board is great because you can choose your own frequencies - I had a TON of parts, so it was inexpensive, and I wanted to have fun with the enclosure color (the gold and purple make me happy). I went with a 125b enclosure, which is bigger than I normally like, but I wanted to use the Davies knobs.

Can't wait to get it running with the others!

Hey all! I did some builds - more to come, but here's a couple of "husky boy" pedals. Why in quotes? WELL...




I'll start with this: they sound SO GOOD! It feels more like amp distortion than my overdrives - amplifies my guitar's tone, but doesn't affect it like overdrives can. I wired the bass/treble in reverse so it felt more natural turning them up or down - call me old fashioned, hehe.

The long version: I wasn't 100% happy with my overdrives. I had A LOT of excess parts and a bunch of etching materials, so I was going to etch a single-sided version of the husky boy and put it into a 1590b. The madbean board would've required some small parts orders, which I was trying to avoid.

By the time I got finished designing the board, I had decided to use a Gorva 1590a and had JLC manufacture the boards - I just didn't wanna deal with etching when JLC is not expensive and can do multi-layer PCBs (no jumpers!).

The Gorva 1590a is fantastic... If you're in 1590a pedals, hehe... I hate making pedals in 1590a enclosures for varied reasons, mainly it's just too tight on space. The Gorva 1590a is about as tall as a 1590b, slightly wider and slightly longer than a 1590a, and the bottom is seamless with the mounting screw holes only at the bottom, so there's more room everywhere inside. As I try to use up my weirder parts (like the giant caps), I was able to use those and normal parts. I was also able to use a mixture of 16mm and 9mm pots to use up some stock there.








The j201s are SMDs on small adapter boards - not pretty, but do the job - I hope I never have to deal with SMD ever again, but j201s are just not around anymore.

Recommended build (but buy it from Brian - his is cleaner, hehe. I'll be shooting some dollars to his PayPal in the coming days for the excellent doc and schematic, tho).

If it gets the job done... ;-) hehe.