Info about the original:
Mark Sullivan from daddys.com wrote this
The Mudhoney is a Distortion/Fuzz pedal with a very wide tonal range. It features a typical 3-knob gain/volume/tone layout plus a boost switch. I played this for a few minutes with the boost off and it is quite impressive; very thick tone with warmth that could quickly find its way to being your main dirt for jazz, blues, etc. Then I pushed the boost and cranked up the gain! The speakers in my little Princeton cried for mercy. Hitting it with the bridge pickup of a Les Paul brought sustain of Spinal Tap proportions. Chords were a menacing wall of sound but yet unlike its name would imply, the Mudhoney didn’t get muddy and muffled. Note and harmonic separation was impressive giving a very dimensional sound at gain levels where most pedals sound flat.
Features
This baby is designed for those who want an in-your-face wall of guitar sound jumping of the speakers.
The boost button and the tone knob enable you to dial in every sound you like right from ultra fuzz to smooth jazz sounds.
In "OFF-MODE" (with the boost-function bypassed) the Mudhoney delivers moderate gain and a smooth rich sound favoured by many jazz-guitarists.
For a more hairy sound, -just hit that "boost-button" and feel the rumble from hell.
The BOOST button switches between moderate- and high gain.
The GAIN knob controls the distortion amount.
The LEVEL knob sets the overall volume
In mid-position (twelve o’clock) the volume level is 1:1. When turned full over (clockwise) the input signal is boosted 15dB.
The TONE knob affects the top end (edge) of your signal without compromising sonic quality, allowing you to dial in the perfect tonal flavour for you taste.
The Mudhoney is a Distortion/Fuzz pedal with a very wide tonal range. It features a typical 3-knob gain/volume/tone layout plus a boost switch. I played this for a few minutes with the boost off and it is quite impressive; very thick tone with warmth that could quickly find its way to being your main dirt for jazz, blues, etc. Then I pushed the boost and cranked up the gain! The speakers in my little Princeton cried for mercy. Hitting it with the bridge pickup of a Les Paul brought sustain of Spinal Tap proportions. Chords were a menacing wall of sound but yet unlike its name would imply, the Mudhoney didn’t get muddy and muffled. Note and harmonic separation was impressive giving a very dimensional sound at gain levels where most pedals sound flat.
Features
This baby is designed for those who want an in-your-face wall of guitar sound jumping of the speakers.
The boost button and the tone knob enable you to dial in every sound you like right from ultra fuzz to smooth jazz sounds.
In "OFF-MODE" (with the boost-function bypassed) the Mudhoney delivers moderate gain and a smooth rich sound favoured by many jazz-guitarists.
For a more hairy sound, -just hit that "boost-button" and feel the rumble from hell.
The BOOST button switches between moderate- and high gain.
The GAIN knob controls the distortion amount.
The LEVEL knob sets the overall volume
In mid-position (twelve o’clock) the volume level is 1:1. When turned full over (clockwise) the input signal is boosted 15dB.
The TONE knob affects the top end (edge) of your signal without compromising sonic quality, allowing you to dial in the perfect tonal flavour for you taste.
(Edit on 2023/01/03 - Note that there has been a new version of the traced schematic and we have a layout for it here. It may or may not sound closer to the original Mudhoney.. Read more about it on FSB / Miro)
Sweet.. thanks for this man. Will probably get it built up next week after pay day.
ReplyDeleteBuilt this today, i had neither a bc546 nor an op07cp (both been ordered) subbed in a bc547 and an lm308 and it works a treat so i guess you can say the circuit is verified, though obviously with the subs it will not be identical to the original. However the subs have still made it a really good pedal, deffo a keeper. Played around with the diodes too and i think i`ll opt for a switch with 1n60p`s and a pair of red led`s. Will build another board for a stock circuit when the parts arrive...... or maybe not as i`m very happy with what i got. Thanks for another great layout.
ReplyDeleteHave you modified anything on the layout?
DeleteI have built it, and it is not working.
No it hasn't been altered since it was verified
DeleteThat's great, thanks for verifying. 5 to go!
ReplyDeleteI assume it would be ok to use a 47p capacitor instead of the 33p going from pin 8 of the ic? I just don't have a 33p on hand.
ReplyDeleteYes no problem
DeleteI've got a few questions. For some reason I am only getting a 1:1 volume when the level is all the way up. I did use a 1uf ceramic rather than a 1uf radial. Could that be the reason? also when the boost is on the gain seems to go from nothing to crazy with very little movement of the gain pot.
ReplyDeleteAlso, I am getting some loud popping when I turn it on and off even though I have grounded the input.
DeleteNo 1u ceramic should be fine so something must be amiss elsewhere. Look for any dodgy solder joints and reflow if necessary. LEDs can often cause popping too, so if you've included a pulldown resistor which should sort it in terms of the effect input, then it will more than likely be the LED. Have a look at this:
Deletehttp://www.muzique.com/lab/led.htm
So I've replaced the LED, and swapped the 3pdt switch out once (first one broke) this second one is giving me some trouble to, not switching back ti true bypass, just going silent. And I'm still getting the loud POP! Could it be the 3pdt switch? or does it have something to do with the high gain circuit?
DeleteAlso I even just unhooked the LED to see if that would solve it and I was still getting the POP
DeleteHas anyone tried a lm308 in this thing? It makes for a better chip in the rat so what about here?
ReplyDeletehi,
ReplyDeletedid you remuve the buffer?
Something has gone horribly awry here, Mark. Chip would need to be on copper side, as mirror image shown. D'oh!
ReplyDeleteThat bc456b is PNP correct? Think I could get away with a 2n3906?
ReplyDeleteIt says BC546B and it's NPN. The 2N3904 should be ok if you have them
DeleteHerp derp. hahah, I need to sleep. Stop posting so many layouts! lol
ReplyDeleteHa ha, you're just like my wife, it's always my fault! :o)
DeleteIs it the 2.2 that controls the gain of the IC?
ReplyDeleteNo the gain pot controls the gain of the IC. the 150R sets the minimum gain and the pot value sets the maximum.
DeleteWell, the only change I made was using a 3.3k instead of 2.2, now if I understand properly, that means that i've changed the corner frequency of that rc filter. The mode without the boost is MUCH lower gain than the clips, and that's the only change I've made.
ReplyDeleteJust having some trouble with this one, but I guess this is more of a general troubleshooting question. When using an audio probe if I touch the output (from the level pot) I can hear the effect OK and it all seems to work correctly. If I put it on my test rig, I don't hear any output at all from the effect. At first I thought my test rig must be faulty so I tried an effect I know that works on it, and it worked fine(!) so the test rig must be good. The only difference I can think of is that the audio probe is attached to ground, so does this mean I have a problem with the ground part of the board?
ReplyDeleteThe sound is close to the original? I found a schematic and it's different from this. Removing te Buffer, there are some components missing in this layout.
ReplyDeletePost a link to the schematic. The scheme for this was traced by a member of freestompboxes.
DeleteOK so I rebuilt the effect from scratch with all new parts... I get exactly the same problem. When I touch the audio probe on the pedal output it works perfectly. All the controls function as they should and the effect works fine. However without the probe when boxed up I get nada. Am I missing something obvious here, this is driving me crazy! Any help/suggestions much appreciated!
ReplyDeleteP.S. the pedal works fine when bypassed so I'm sure all the off-board wiring / jacks are sound.
DeleteAre all your grounds connected together? Board, I/O sockets, DC adapter, switch?
DeleteYes all grounds are connected together, pics to follow shortly. Even when i attach the audio probe without the ground at least i hear a buzzing rather than nothing at all... what's the best way to test the ground from the board is working?
DeleteJust check for continuity between all points of ground. As long as there is continuity between them all it should be fine.
DeleteOK all points of ground pass the continuity test, if I put a probe on the ground output of the board that's fine too. The whole bottom row of the board passes the test. Anything else other than grounding that could be causing this?
DeleteHeres some pics of the wiring https://plus.google.com/photos/116241861790572354815/albums/5851159051084585457
So just to recap:
- It works fine bypassed
- The LED lights when I engage the effect
- When I engage the pedal I can hear the effect working OK with an audio probe on the output jack.
Thanks again for the assistance, really appreciate it. So weird cause I've build about 15 of your layouts so far and had only a couple of minor issues, this one just wont play ball!
Anyone got any ideas on whats wrong? Help!
DeleteIf you can hear the effect working ok with an audio probe on the output wire, but not when you have a cable in the socket to your amp then it suggests that something is wrong with the socket. You haven't got something shorting against the tip have you?
DeleteHere is the schematic that I've found on the web.
ReplyDeleteI don't know if it's correct or no. It was just an opinión, if your scheme was traced by a member of freestompboxes, I'm totally sure it's close to the original. Thank you.
http://guitar-gear.ru/articles/TRex/TRex_Mudhoney_sh.GIF
The schemes look fairly similar, they're both obviously modified Rats and it could be that they were both traced from different versions of the pedal which would account for the variation in some of the values. Also bear in mind that the scheme you posted shows all the switching components which have been omitted in this layout in favour of our usual 3PDT stomp switching. So the 4013 IC and related components including the bypass buffers aren't required.
DeleteOK so it gets weirder...I was messing about with the ground connections, all fine. I changed the output jack, no change. It still worked with the audio probe, and I noticed that the only difference between that and the output jack in the box was the 100n greenie cap that was attached to the probe. I soldered the cap between the output from the 3DPDT and the output jack, and hey presto. What would the cap be doing that would make it start working?
ReplyDeleteSo its boxed and working, however I've still got a few issues that suggest something definitely isn't quite right. The tone knob seems to be reversed, is that correct for this build? (I.e. it gets brighter when turned to the left, darker to the right).
When the treble and gain are turned up in boost mode i get a shrill high pitched noise...
In non-boost mode the gain is a lot lower than in the mudhoney demo video.
I've got another mudhoney circuit that was having the same issues so I'll try that with a cap on the output to see if it solves it. On concern I've got is that when the effect is bypassed the signal will be going through the cap...will this affect it? I guess i could put the cap between the board output and the switch input...
I've put some more pics up of what I've done in case my ramblings don't make sense...
https://plus.google.com/photos/116241861790572354815/albums/5851159051084585457
Thanks
Jack
I just built this again from scratch will all new components and there is definitely something wrong with the layout.
ReplyDeleteIt only works with a cap on the output.
I do believe you're correct. The schematic shows that the Level 1 is connected to vref like in the layout - but - the switching buffers have been omitted, so the level control just simply won't work as it is in the layout. You're getting vref to the Level pot and passing that on to your amp..
DeleteTake the Level 1 to groung strip instead of vref where it is now. You should be golden with that...
+m
That won't cause a problem. Vref is a virtual ground and acts in exactly the same way as real ground, it's just somewhere the signal can be dumped to.
DeleteHmm.. Weird. There still is 4.5V on that rail. In my understanding it would still need a cap after volume 2, if the pot mixed signal with output and 4,5V - As that would have the signal and 4,5V pushing towards the amp..
DeleteI believe Jack got his working once he took volume 1 to ground...
+m
I see what you're saying about it and dumping to ground always seems to makes more sense to me and . I'll alter the layout to use ground, but I'm interested how dexxxy's worked ok, unless he assumed the Vol 1 connection dumped to ground maybe? Thinking about it there will always be DC there without a cap.
DeleteIt is common practice to use vref virtual ground for dump at volume control, but that's always followed by a buffer or electronic switch setup. A few designs use vref, and simply have one more cap after the pot. Noticed this with Marshall Blues Breaker just today (planning to build one soon).
DeleteWhile IC sees the vref as virtual ground, the amp doesn't see it as nothing more but 4.5V DC:)
In Dexxy's case, i would assume that he just grabbed vol 1 from the bottom row without thinking about it:)
Hope your trip was good and welcome back!
+m
i'm trying to do this effect but where is connected switch3?
ReplyDeleteIt's not connected anywhere. It's just an on/off switch, in one switch position you close the circuit, in another it stays open (wires disconnected/not connected to each other).
DeleteAlright, my comment just disappeared?
DeleteAnyhoo... it's not connected anywhere as it is a simple on/off switch. The wires are either connected or disconnected, second throw does nothing except keeps wires disconnected.
No connection. A SPST switch will do the job but they are less common in those mini toggles and when I have seen them they were more expensive than the SPDT switches, so you may as well just use the SPDT you're more likely to have in stock as shown, and only use one of the throws.
DeleteSomething is happening to this thread. I've answered this question twice and every time it dropped my entry. Some sort of blog limitation?
DeleteNot that I'm aware of mate. The only problem I know of is the 200 comment limit which can be a pain
DeleteMaby I'm stupid, but exactly how do I connect the switches to the board?
ReplyDeleteIs it like I think...? Standard 3PDT switch with IN and OUT (from volume pot) and the boost switch pin 1 and 2 to the board where it says "Sw1" and "Sw2"?
Sounds great and very much like the original I used to have but the sweep of the gain pot is just crazy. Jumps from almost nothing to almost full blast right at the beginning. Gonna try a log pot there.
ReplyDeleteOk, I put a 100k log in there, now the taper is near perfect. Definitely worth trying.
DeleteHello, can you help me?
ReplyDeletemy:
Q1 C:6v B:1,35v E:1,77v
Q2: D: 6v, S: 1,5v, G: 1,7mV
its correct?
Being Q1 collector and Q2 drain directly or linked to the +9v rail, I'm afraid that something's wrong. Id check the 100ohms resistor value or the solders in this rail.
DeleteBR
i replaced the 100ohms ressitor to real 100ohm, and now the Q1 c:5,48v Q2 d: 5,48v
Deletebut still not sound
Anyone tried this out on bass?
ReplyDeleteI just had a play on a real one, decided to check out the layout. One thing i noticed was that the tone knob just rolled off treble, wasn't one of those more bass or more treble knobs. And anything under say 3 o'clock was not nice. So maybe if change some cap values (not fully sure which caps) or make a buffered blend? It could add some mad growl whilst you keep your bottom end.
DeleteCan't seem to get this one to work, bypass works and the LED works but when I turn it on, no sound whatsoever. Any idea what I could try to find the problem?
ReplyDeleteMeasure the DC voltage between all transistor and IC pins and ground. That should give a good idea where the problem is
DeleteI used to run a little green wonder before this just to get a fat ass lower mid boost. I think I'm going to shoot for a modded version to achieve that sound with the mudhoney alone. Any ideas on how to approach that? I think I'm gonna start with just upping the input cap 'cause I run the gain at about 12 o'clock and it starts to get fat only after that. I have an idea of what components to play with but if anyone has a better understanding of how this circuit works, help is appreciated!
ReplyDeleteIncreasing the input cap may help and so it's always worth trying, but you'll get more of an affect by altering the high pass filter at the inverting input. As standard there's a 2K2 and a 100n to ground which gives a cutoff frequency of around 723hz, and so you might want to try something like a 220n which will drop that cutoff frequency to 328hz meaning you'll be getting no attenuation between 328 to 723hz, which is right around the lower mids frequencies.
DeleteThat's pretty much where I was looking at but thank you VERY much for the specifics, I'm not too familiar with the math. Also thinking of playing with the tone stack.
DeleteHi,
ReplyDeleteI build this one and it sounds very good! thx!
Everything works normal but, is it possible that I get noise comming true when my guitar is plugged in?
Thx
Having some troubles and I'm not sure if it's how the pedal is supposed to sound or if there is something wrong. If something is wrong all the things may be related I think:
ReplyDeleteFirst, difference between normal and boost is MASSIVE, when gain and volume are at 12o clock my overdrive sound is quieter than my bypassed sound, this same setting on boosted results in full on fuzz (sounds good though).
Normal mode also doesn't have a lot of bass to my ears...
Second, on boosted the gain really doesn't add anything more above 12 o clock, all drive seems to happen before that.
Third, my tone control works backwards, counter clockwise results in more treble...
Any Ideas?
Thanks !
First and second: same thing is with my project. Original mudhoney has FET switching bypass, not true bypass. I think that maybe this is causing that problems, because in FET switching bypass there is one more gain stage on the end of the circuit. Third: switch level 1 and level 3 and problem solved.
DeleteWith the gain all the way up, my build is self oscillating when in boost mode, but just with the guitar plugged in. When I disconect the cable, the noise stops. Any ideas?
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ReplyDeleteI couldnt find my problem in my previous build so I build I second one from scratch, the EXACT same problem, so not very sure this is totally verified as is.
ReplyDeleteProblame I have is that unity gain vs my clean sound is gain at 50% and volume at 100%, anything below that is just quieter than my clean sound. When I switch the boost however, I get full on fuzz at a much higher volume. I once had an original Mudhoney and it didn't acted like this, and I'm pretty sure my build is exactly right :(
Same thing with my too. I thought that is because it is missing the bufferd bypass, and i made it with buffered bypass like it is on the schematic with 4066 and 4069 chips and with one more transistor, but iti is same as this version with true bypass, nothing really different, same amount of gaine and same volume issues.
DeleteI don't understand why the gain section of this layout appears to be nothing like the schematic?
ReplyDeleteI'll hold my hands up and say I haven't built it on vero, but on a breadboard and modelling it on a PC it performs with the issues described above. No gain until you push in the boost switch and then all the gain! ;-)
What doesn't match? The gain section has a 150R resistor from pin 2 which then goes to the Gain pot. The other side of the Gain pot then goes to pin 6. All with a 100p cap in parallel between pins 2 and 6. The switch then brings the filters (that are always in circuit with a Rat). So the Boost switch is just changing the frequency response.
DeleteThe two schematics I have for this both agree on that gain structure.
https://ibb.co/mX13s2n
https://ibb.co/LJTHVMr
Both of the schematics are wrong, they must've been the result of the same incorrect tracing. I've just traced an original Mudhoney, and instead of trying to type out the differences, I've made corrections in the schematic - the correct way is this: https://ibb.co/x5pNG1H
DeleteAlso the drive pot of mine is a 47K log instead of the linear 100K pot
The 2.2k resistor is moved in your corrected schematic, but where is the 100nF (C1 in the LJTHVMr schematic linked above) It is missing?
DeleteHmm.. I think I will have to take a deeper dive. I mainly tried to figure out just the boost problem. I've incorporated the changes in my build, and the boost works much more as it should - but something is still off compared to the original. I will try do do a full trace and a new schematic in the next days.
DeleteI've now tried to trace the whole thing - here is my schematic: https://ibb.co/xzj3KDW
DeleteAlso, to answer your question from earlier, C1 actually doesn't exist. In the old schematics there are 22 capacitors, but in reality there are only 21 in the circuit. So there must have been some small mistake happening there.
My pedal is a v1.1
Have a look and please notify me if something looks off; even though I think I've been over everything a few times, something surely can be missed or mistraced. Also, this is my first trace.. :-)
It's a good trace. I'm still a bit skeptical if the 2K2 in parallel with the gain pot would work. Don't have the pedal myself, so i can't check it out. But.. If you are sure, well then..
DeleteGuess i'll need to draw a v1.1 layout soon :)
Being the skeptic i am (quite compassionate, in merseyside style), i asked the same question on FSB. My first gut feeling says that it shouldn't work like that. But i've been proven to be wrong before.
+m
I was quite surprised myself when I traced it, as I too find this a bit odd. Actually, to be absolutely sure, I just went over it again... They are in fact parallel as written in the trace. :)
DeleteThere's a new "V1.1" layout up on the page... :)
DeleteThanks K!
+m
Possibly you didn't connect pin 2 (op amp) to the 2.2k->100n->Gnd? That would explain unity gain until boost is engaged.
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