welcome to Apocalypse Audio, your haven for DIY guitar effects in the end times. so, start prayin to the fuzz gods, savin up those parts, and remember, when the big one goes off- keep your transistors shielded from those pesky electromagnetic pulses!



so i finally got my buddy's dirty boots finished.  it's going to be used on guitar and organ, so i added a couple extra controls.  a pre-bass and post-treble tone control combo work great together.  this is the main recipe for filtering distortion pedals, so it's no surprise.  i plan on doing a full overhaul of this design in the future, to see if i can optimize it any further, but until then, this one sounds great.  here's the schematic i ended up with.

and some gut shots.

 unfortunately i ran out of alpha pots in the values i needed, but the ones i ended up using are of decent quality.  here's a couple clips i made of the harder fuzz that this pedal can do.  the first is the DB by itself, the second is boosted. disregard the titles. it was 5:30 am when i got this thing finished last night.



recently, keith from the band MY COLD DEAD HAND, asked me to replace a faulty switch on his Black Russian Big Muff.  well, of course i couldn't just leave it at that!  i rewired the whole thing, and added lots of new modifications.  it turned out extremely heavy and doomy.  he loves it! this is what i ended up with-



ok, when jamming with my buddy who is a keyboard player a while back, I brought my DB prototype along. I kept telling the guy his organ sound needed some grit, and he kept telling me his Nord synth had distortion built in, no need for a pedal. (wha??) i finally convince him to plug in the DB, and holy shit- perfect Hammond organ overdrive. smooths out the digital top end and everything. sounds fantastic! so now of course he wants one. I slapped one together with some GT313s I picked up a while back, and I realized jus how noisy these things are. they have a great smooth top end- I think due to their very low frequency response, but man do they hiss. I can see why I wput such large Miller Effect caps in the original. so I tried some others- for Q1, I put in the lowest noise devices I have- an American made 2N1307. it was untested, but these have low leakage, and usually have gains somewhere around 100-120. I found that Q2 is much more critical. GT308s to work fine, but didn't have the right overdrive sound- more of a fuzzy distortion. I found an MP16 with a gain of about 50, and that was very nice sounding, but it was the only one in the batch that i had that had that sound. there was a strange "3" stamped on the top of the can in red. probably some sort of sorting mark. to get the classic dark and full DB sound, I think a 313 in that position is still the best. nice smooth sound. higher gained transistors like the 308 and 1307 provided an excellent fuzz sound, but the lower gain models really work well in the second position for a germanium overdrive. now, I didn't tweak any values at all, just swapping trannies in sockets. I had collector resistors of 100R, so by raising those, and adjusting collector biasing you could probably make others work as well.

so just because you don't have the exact transistors, you can still build a Dirty Boots! just experiment, and find a use for those low gain Ge's!!



HERE is a post containing customized string tension charts. most strings don't have what are considered "proper" string tension- meaning they don't have even tension on each string. these customized string guages are supposed to remedy this situation, supposedly making quite a difference in your guitar setup. I haven't tried it yet, but I plan on it sometime soon. if anyone has tried this before, let me know!



HERE is a link to my entry in the design contest over at FSB. it's the preliminary version of a new germanium vibra/trem circuit. I used the basic oscillator from the magnavibe(with some tweaks), and went from there. I did a write up and a hand drawn schem, but once I get everything proper, I'll post it here. take it easy!


just a little update.

haven't posted in a while, so I just thought I'd say a couple things.

first, I noticed that I've got a few new followers on the blog, and just wanted to say thanks for signing up. this blog has basically documented my pedal designing fun, from novice to just a bit more than novice. glad you think it's worth hitting that button.

second, I have a couple new projects in the works. one is called the Vintage Vocalizer, and the other is a vibe/trem called to Dirt Devil. the first is an effect for vocalists that like that old nasty sound of blown mic pres slammed to taped from th days of yesteryear, or full on jourgenson-esque nastiness. if you ever thought your vocals were just too clean, this thing will be the thing for you. it's based off an older design that uses a cascode gain stage, and for some reason, this type of stage just works great with vocals. it really avoids that "I'm singing through a fuzzbox" sound, and breaks up just perfectly when you lay into it. it'll have a 1/4 in input so you can still use it as a guitar pedal, a transformer coupled xlr in, and a parallel xlr out- so you can send some of your clean vocal to the PA or monitors if you want. the output will have to be coupled to a direct box, unless I figure out how to add a balanced out by then. although, I like the idea of unbalanced, because it is a really nice booster for guitar as well. optimally, it will have both, but we'll see.

the Dirt Devil is a vibrato pedal that I came up with after toying with the Magnavibe over at FSB. i made some upgrades, modifications, and added some new controls as well. first, a FET buffer was added on the input to help with the grisly input impedance and brighten things up a bit. then, the main transistor in the preamp was changed to an NPN Ge, because attached to it are two new controls. the first is labelled Grit, and added a bit of gain and drive, giving it a nice vintage pumping feel, and makes it able to change the texture considerably. the second is a symmetry control, which can take this thing into all kinds of different wobble territories. you can get an almost chorus like effect out of it at times. these controls also allow it to be used as a great booster when the depth is turned down. hopefully I'll have this guy ready to show by the end of the month for the circuit design contest over at FSB. of course schematics will be posted when I get them drawn up.

take it easy!



here are some clips of the four horsemen into the toecutter. heavy ain't it? I think I might like to put these both into one box.



i recently found this great article about some handy electronics tools that might not have hit everyone's radar. besides these, I would personally like to add the rounded needle nose pliers to the list. they are perfect for bending leads and routing wire without marring the insulation. happy building!




THIS is pretty hilarious.


here is a 4H i built up for a very patient member of FSB. I think it turned out pretty well! below that is the latest schematic with the output buffer added. click on the image or link to see them fully. such is the way when blogging from your phone!

I really kinda dig this layout, too. it gives the user the option of positioning the pedal vertically, with both jacks on one side(saving space), or horizontally, with top mounted jacks. the knobs on the front side keep them well out of the way of the stomping foot, which also leaves a nice canvas for whatever graphics might be used. sooner or later, I'll have to decide on a form factor and stick with it, but as of right now, every new pedal is a different challenge. I'm kind of looking forward to the day when I don't have to measure everything out for the new box, knobs, and layout I'm using, but it's definitely helping me get my chops up.

btw- I have since separated the battery wire from the input cable. even though it's shielded, and I heard no hum, I wanted to be sure, and it's just good practice.

Photobucket Pictures, Images and Photos

HERE is a link to the latest schematic on freestompboxes.org.


after seeing THIS VIDEO, I was once again intrigued by the MONTARBO SINFHOTON. after finally hearing it, i figured I would whip up a vero layout. you can find it in THIS THREAD ON FSB. I'll try and get around to building it soon, but it has been double checked by another forumite who could only find one small correction, which is detailed in the thread. later, I will also post a layout for the earlier two knob model. a nice modification to this circuit would be a pot on the input for gain, as it is fixed in the original.



HERE is a cool article from an issue of the Journal of the Audio Engineering Society of New York circa 1973 entitled "Tubes vs. Transistors- Is There an Audible Difference?" it's a neat read, and probably one of the first times solid state designs were thought of as less desirable sounding than tubes.



HERE is a link to the Paia forum with 4 pages worth of projects and their original documentation.  included is the ubiquitous Rocktave Divider among others.  unfortunately many designs use the now extremely rare 4136 ICs, so the layouts will have to modified or redrawn.  none the less, the schematics are there, along with breakdowns of the circuit as well as construction instructions.  check it out.  i'm sure there is something there from the Paia workshop that you haven't yet seen..

FSB forumite roseblood, pointed out to me that you can get the 4136 on eBay pretty easily. he's got a vero layout that uses a 4136 for a dual tube screamer circuit. check it out over at freestompboxes.org!


spring reverb tanks explained.

interested in spring verbs?  well, HERE is a great article on the Amplified Parts company blog on spring reverb tanks.  i have yet to read it, but it looks pretty cool.



my buddy, martin from soulsonicfx, recently posted his layout for the totally awesome fourbanger.  check it out.  it's awesome.



a better treble bleed(bright cap) circuit?

on the guitarnuts forum, someone recently posted a new way to implement a treble bleed circuit using a cap, a resistor, and a dual potentiometer. the idea is, to properly emulate the frequency boost you get from the inductance of the coil in the pickup, even when your volume is rolled back. you can find the schematic, complete with frequency plots for a number of different treble bleed circuits HERE. now, how to incorporate it into a stompbox gain control...

adding a logo to your Eagle files

HERE is an excellent tutorial on Tasif Khan's page that shows you how to import your own logo for use in eagle. this is a great way to get past the limited amount of fonts that eagle has to offer. although, I have to admit, I do have a small spot in my heart for the vector font. it's just so damn old school!

capacitor switching techniques

cap switching is a great way to get more sounds out of your circuits. positioning switches at coupling caps(input or output), bypass caps, bright caps on gain controls, or tone controls can unleash options in circuits that you didn't know you had. here is a great article on Rick Viola's site where he goes in-depth into ways of cap switching that you might not have thought about yet.


pot codes

the legendary Joe Gagan found this info on a vintage radio site. I thought it was definitely worth reposting. thanks, Joe!

found this info at an old radio parts site.
this info may apply to pots made between 1930s through 60s, possibly into 70s and 80s. use the following at your own risk:

       Z = audio taper
       S = linear taper
       V = c bias taper (right hand taper)
       T = ant. & c bias taper
       U = left hand ant. & c bias taper
       W = left hand taper
       L = left hand taper
       N = left hand taper (screen grid, regen, phono pickup)
       Y = audio shunt & AVC when taper desired

       Tapers: Z = Audio Taper, S = Linear Taper


       IRC POTS: I have some "B" elements (like "Q")
       than can be used in custom pots - inquire
       They can also be used to make gang controls
       but I have no time or knowledge to make any
       complicated controls

       IRC TAPERS:
       13 = audio
       11 = linear
       14 = reverse taper
       17 = special or tone audio
       18 = special or tone audio
       19 = special or tone audio

       Most of the IRC pots with taps are for
       use in volume and tone audio circuits

       Example: Q13-137 is a audio taper pot
       Example: Q11-137 is a linear taper pot.


       Allen Bradley (Ohmite) tapers:
       U = linear
       J = taper (such as audio)
       A = unknown taper


       CENTRALAB / CRL tapers:
       6 = audio taper
       1 = linear
       2 = right hand taper
       3 = taper both ends
       4 = short taper, left end
       C1 = linear taper
       C2 = audio taper
       C3 = reverse audio taper
       C4 = audio taper - modified log 20% center,left hand
       C5 = reverse audio - modified log 20% center, right hand
       C6 = semi linear taper modified log 40%, volume, ant. shunt, c bias
       C7 = semi linear taper
       C11 to C17 = volume with tone comp.

       #1 = audio taper
       #2 = logrithmic right hand taper
       #3 = left/right taper (ant., Shunt & Bias Circuits)
       #4 = linear taper



alright, as promised, here is my latest fuzz. I described what I was shooting for a bit in THIS post. basically, I want to simplify my dirt setup, getting rid of the need for a boost, and I wanted it to be extremely versatile, with the simplest amount of controls.
now, the style of music I've been playing lately is influenced by sixties style blues punk a la gories, sonics, oblivions, them, dirtbombs, blue cheer, black keys, etc., so I really wanted to pedal to be able to do a nice, low fi-ish, but very musical, overdrive- similar to a blown up tweed, as well as a high gain sixties style fuzz for the single string square wave kind of sound. most sixties fuzzes really do not have enough sustain, and the ones that do, lack that phased out fuzzrite kind of thing that is so cool about sixties fuzz. so, since we are talkin simple here, I want to get all of that from the volume knob- none of that double stomp switch shit.
what design cleans up the best, and has that crazy impedance thing that actually brightens up when you roll back your volume knob? you guessed it, the venerable fuzz face, perfect for the first stage. many folks will bemoan the FF's input impedance, saying it ain't proper and all, but remember- this is all about simplicity. I don't need it to "play nice" with other pedals before it. it's gonna be first in the chain, and there it will stay. the clean up quality just simply outweighs any negatives that might come up.
so we have the base fuzz face design, but hey, that's kinda boring right? and it won't do the zip gun fuzz that we want with the volume dimed. enter transistor number 3. your basic inverting amplifier, but with a catch. after it is a good amount of negative feedback connected to the output of the FF stage, set up kind of like a fuzzrite with the gain almost all the way up. this gives it that bit of out of phase edge, as well as taming the gain and noise a bit, with the 4n7 cap reducing some highs.
after the fuzz face/rite action is the tone control. I wanted something that was going to be very versatile, just in case someone else isn't into the same exact sounds as me, or if it gets tried out with bass or whatever else might come up. the tc is similar to a muff style control, but the high pass cap is switchable into three ranges. the stock .001 cap gives you a very scooped sound that can do extremely bright, or rolled back gets into doom territory. adding in the 3n3 cap is usually where I keep it. you get a great upper mid crunch, that sounds great with the volume rolled back(think lofi tweed explosion), or does a nice cutting fuzz turned up. with the final option, the .01 cap in parallel with the stock 1n, on one side the heavy lows get filtered out. this gives you a nice full range sound without the mud. great for folks that want to use this as an overdrive. on the other side of the pot, all the highs get rolled off, leaving the low end intact- perfect for a fat bass sound.
you have probably noticed that this circuit uses PNP Ge transistors, so I threw a max1044 voltage converter on the power rail, so guys can use regular center positive DC jacks. all transistors are low leakage 2n1307 Ge's, with around 100-120Hfe. the pcb is not verified yet, although it is fully checked in Eagle. I will be building one up shortly for the other guitarist from the Dead Feathers. I think it'll be perfect for him.
so, there ya have it- the Naga Fuzz. i was going to call it the Nagasaki, but glorifying all that carnage made me feel kinda creepy. so now it's named after the freaky reptoid alien dudes from ancient Indian histo... I mean mythology;). look em up, some wild shit. I hope some of you guys at least take the time to throw it on the breadboard, I'm pretty happy with it. i'll try and get a YouTube video up soon.

first mod! adjust R14 for more/less separation between the two filters in the tone stack i.e. more/less low/high end roll off at the extremes. for bass, try omitting it all together. my prototype has a 100K pot here. perhaps I'll ad a trimmer in a later revision.
gah! I just noticed the power filtering caps along the bottom of the board are just barely uneven. I'm going to have to fix that, or it's going to bug me forever!



here's a clip of the Green Bomb that FSB forumite pillof made a while back. I stupidly forgot to add it to the blog. thanks pillof!!

FEATHER FUZZ #1- and POST #100!!!

hey, it's post number 100! let's party!! man, this blog has been fun so far, so I'm looking toward 100 more. thanks to everyone who has been following along with me, your comments mean a lot, and I hope to see you around in the future. here's my latest pedal that I'm rather proud of, I think it's fitting for the big 1 0 0.

i've been commissioned by a great band out of Champagne, IL ,called the Dead Feathers, to create a couple of fuzzes for them. they weren't satisfied with their current fuzz tones, and i told them i'd be glad to give them a hand. the first one is for one of the guitarists that plays mainly fingerstyle guitar. he was looking for something with a decent amount of attack, and they are into the garage rock/sixties style stuff, so i thought the Green Bomb would be great. i added the addition of a JFET input buffer, because i feel it evens out the inconsistencies that can come from playing with ones fingers, and it gives the signal a bit of extra oomph that might be needed to keep the attack when playing without a pick. i did the layout on vero, as i don't have a pcb made up for this particular design yet, and made a few modifications when i tuned the circuit by ear. the pedal has some cool, old, low gain, two-tone, T-106, Si transistors i picked up a while ago from a surplus guy on ebay, and pretty much run of the mill metal film resistors, box caps and a couple ceramics in the filter sections. the electrolytics are some nice audio grade ones i just picked up from a dealer in poland. another thing i did with this build, is instead of snapping off the tabs on the pots, i drilled the extra small holes, and mounted them properly- thats not something you see a pedal builder do everyday!;) Dirk Hendrik would be proud! the finish is an awesome plum sparkle with dark green heathkit knobs, topped off with extra large rubber feet and a green led. it really looks killer in person. the pedal is sounding really cool too, and i think he'll be happy with it. stay tuned for the second pedal- it's going to be an all new design.
disregard the scuff on the the tone knob.^^^ it's getting replaced.

sorry the 2 pics above are kind of blown out, i took them indoors in crappy light.  although, they do kind of have a cool early seventies grainy b movie style to them that i kind of like!


transistor testing app note

HERE is a link to a cool .pdf app note on transistor testing. it should come in handy when you aren't sure if you've got a dud or not.



I just wanted to give you guys a heads up- the next generation of Apocalypse Audio fuzz circuits are being cooked up as we speak. I have been putting one of the latest through it's paces during practice with my latest project, and it's coming through excellently. the idea was to have one pedal that can clean up into a nice overdrive with the rollback of the volume knob, and can be turned up into a nasty, but musical, old school sixties style fuzz with tons of gain on tap. I wanted to be able to use one fuzz, and be able to get multiple tones, with enough gain that no booster was needed. this would allow me to simplify my pedal setup considerably, which has become a sort of mantra of late. what I ended up with was a sort of 3 transistor fuzz face/fuzzrite/big muff frankenstein hybrid that has enough flexibility to be usable with any rig and go from wooly, to cutting, to clear, whenever you want. it also is able to clean up in a sort of jekyll and hyde fashion- for overdriven chord work, or single string stun gun action with the flick of the wrist. stay tuned for schematics, project files, and demo videos soon.


HERE is a link to national semiconductor app note number 31. it's a virtual bevy of op amp circuits. from the most basic to the obscure, they all have an example in this application note.


fsb moderator, and good buddy, GregG posted this link about the revival of germanium with hybrid Si devices. it's a really fascinating read. Ge kicks ass! FTW!




ok, besides their awesome sweet potato fries, cheap cereal, euro chocolate, and biscuit tins, Aldi has once again made me glad to be a customer. because, today I picked up this awesome vice for under 10 bucks!
(click on the images to expand them)
Photobucket Pictures, Images and Photos
Photobucket Pictures, Images and Photos
I was planning on eventually getting a panavise model to match my panavise jr, but now there's no need. Aldi flips their stock regularly, and changes these specialty items out all the time, so there's no guarantee that they'll have them. but, if you see them there, pick one up, because they'll probably never carry them again!



i thought i'd take a little time to show you guys how i build my prototypes. this is a new fuzz i've been working on that is a kind of cross between the fuzz face and the fuzzrite. usually when i build up a proto for the first time, i'll just grab a piece of vero and start populating, and that's what i did here. i'll try to cut a piece of vero that looks like it's got plenty of room, but this time i think i just made it.;) the boxes that i usually use are these computer switching boxes that i bought on ebay for super cheap. i think i got 8 of them for 15 bucks or so. sometimes i'll stip the paint off with acetone, leaving the box sit in the chemicals for days. what ends up happening is a really cool weathered and corroded finish that lightly rusts and changes with age. i really like the look of it. the pots i've been using are these used mil spec Allen-Bradleys that you can get on line for a buck a piece. i'll spray clean and lube them up to try and bring some life back into them if they need it. knobs will be whatever i've got lying around. many times my pots and knobs don't match, but i don't really care, it's just for me to use. i've got a number of pedals that i've made up for myself like this. usually i'll etch a pcb and put it in a nice box from PE.com if i am happy with the sound. hopefully this helped some of you out there with building your proto effects!

I put this guy through hs paces the other day with great results! I'll post a full write up soon.



here's another little gem I found on the Osvalve site. a great article on tone stacks. enjoy!



a comment from a Russian friend.

I received this very nice comment from a reader of the blog who lives in Russia, so I thought I would share it here.

Good day! I apologize for my English. I'm from Russia. Build your overdrive. Used j201, 2n2222, 2n2907 and 2n5458. I want to thank you for the scheme. Great sound! Previously collected your panzerfuzz. In Russia, the guitar forums, are often discussed your scheme. I wish you further success! People need to like you.
All the best!
Dmitry. Rassia.

thanks a lot, Dmitry! that means a lot, and I'm glad you are enjoying the schematics! I didn't know that anybody talked about any of my projects on Russian forums. that's very cool! if you could provide a link to the forums, I would love to see it. thanks, again, and please tell other Russian builders, that I am glad they like the projects!



here's a pedal i built up for a buddy of mine the other day.  he plays bass in the local chicago trio Hobo and Boxcar, and wanted something that he could use for bass as well as guitar.  i built him up a circuit that i came up with based on the Fuzz Face/Wooly Mammoth model, that shines when it comes to double duty fuzz action.  it's basically a tweaked fuzz face with russian GT309 transistors (a new fave of mine), that has the fuzz factory/wooly mammoth adjustable NFB gate control, an input gain pot, a max gain trimmer, and a LPF/switchable HPF adjustable tone control, similar to the Big Muff, that allows for guitar or bass functions.  the mid shift switch allows anything from fat scooped bass, a dirty overdrive, or mid-heavy motorhead style grind.   for guitar, it's capable of anything from monster thick doom tones to mosquito sixties style fuzz. topped off with some sweet vintage knobs, it's a great switch-hitter.

as an aside, after taking this picture, i realized that i wired the center pots up a little tight, so i simply switched the two middle pots around. now, if the nuts loosen up, the wires on the pots won't get pulled out so easily. a word to the wise- leave enough slack on your pots!



well, i came up with another dirt pedal the other day.  lately, i've been experimenting with mixing different types of transistors together to achieve new tones, and this one kind of  takes that idea to the extreme.  it's designed under the premise that the stages increase in breakup as it goes along in the circuit, but instead of using stages that increase in gain, different types of transistors are used that exceedingly distort as the the circuit progresses.  for instance, the first gain stage is a silicon BJT.  this is used to get a decent push going and a very slight amount of drive.  next, is a MOSFET transistor, which like to distort a little easier, and in a bit more pleasing and richer way than the previous Si transistor.  finally, there is a germanium stage, which of course loves to distort in a very full and heavy overdrive, especially when driven by the previous gain stages.  the result is a very clear, yet complex crunch, that has a very nice character to it.  to round things out, in the beginning of the circuit is a JFET buffer, which helps to increase the current, and gives a nice high input impedance for the guitar pickup to see.  so in the end there is a total of 4 different types of transistors, each of which i tried to use to their optimum potential.  hence the name, the Four Horsemen Overdrive.

the tone control is a variation on the SWTC, but it has an added pole for a steeper rolloff.  the frequency point where the curve begins is rather high, so it is really more like a presence control- just taming the highest of frequencies, keeping the basic tone intact.

this circuit was spawned from a simpler design called the Nice Little Overdrive.  you can see the evolution in the thread over at FSB.


here is the schematic as it is in the latest version.

here is a pic of a vero layout that i built up.

and here is a quick video i made on my iphone.  the video is of the previous version without the high end rolloff presence control, and the bypass cap on the last stage, which adds a bit more gain.  the voice of the circuit is basically the same, but there is a little bit more flexibility.   of course the quality isn't the best, but you can get the idea!  ignore the man behind the camera.



someone asked for a clip of the Dirty Boots, so I dug one up. HERE is a soundclick page by danielzink where you can hear it. if you go to the second song down, it's in the micro pedal demo. you'll hear a phaser first, then the DB. I haven't listened to the clip in a while, so I'm not sure how accurate of a representation it is, but I'm sure it's close. thanks, Dan!