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!



here's a Dirty Boots I built up in an old tank communication control box. it's got some serious mojo(just for fun;))components, a switch for hi and lo gain, and a single volume knob. I like the idea of repurposing death machines for rock and roll. I should've bought more of these boxes when I had the chance! I've got one more, if anyone is interested.

Photobucket Pictures, Images and Photos

Photobucket Pictures, Images and Photos



WTF? more Aussies! when it comes to surviving the apocalypse, everyone knows the Australians know their shit. THIS video proves it.



I'm not sure what's up with all these posts about the land down under lately, but I recently ran across THIS great Australian site that has tons of information on Aussie guitar amps as well as building guitar amps and effects. included are a number of old magazine projects from EA. if you scroll down the page, you'll find schematics for fuzz, compressor, "phase vibrato" Leslie sim, and tremolo projects as well as a number amps. be sure to check out the rest of the site, as it's filled with some very cool articles and schematics, such as fsb forumite Phil's cool reverb project.



here is a very cool little pdf from elby electronics from australia. it includes some nice graphs and instructions on how to alter the taper and value of your potentiometers. it's an essential technique for making the most out of your controls.




i was asked to post a layout for the MLOD, so here it is.  enjoy!  i tried this circuit out with 2n5457, j201, and j309 fets.  they all work fine..  the Q2 position is where most of the magic is.  try different transistors for different tones.  i enjoyed a 2n5210 with an Hfe of 250-300 there, myself.  it had nice midrange content without sounding muddy.  the images are at 600 dpi, a current limiting resistor for the LED has been added, and the gain pot can go up to 10k  that's all you have.  this circuit is a great sounding boost/light OD/ line driver/buffer. i hope you dig it!

take it easy!




i've decided to sell a limited number of Green Bomb fuzzes to anyone who wants to purchase one.  each box will be a bit different, built old school style on tagboard, tuned by ear with whatever high quality components i choose to use at the time and true bypass.  if you are interested, you can get ahold of me at apocalypseaudio(at)gmail.com.  the price will be $150 each.




fsb forumite, helmut shows off his version of the GREEN BOMB called the FUZZ RIDE on his website http://aquataur.at.tf/.  he did a great write up, showing his additions to the basic GB circuit.  helmut added in and output buffers, as well as a sag switch for other tonal possibilities.  there are some nice soundclips uploaded there as well.  make sure to check out helmut's other articles- they are all great reads.  thanks, helmut!



alright, here is my latest offering to the faceless electronic gods of the global interweb.  it's called the Mona Lisa Overdrive after everyone's favorite cyberpunk masterpiece, and dystopian premonition written by William Gibson.  if you haven't heard of  it, check it out!  anyway, on to the the goods- 

i thought i would build something that would turn on the guys that were into the lighter side of things- something different than my usual wall of fuzz tones.  with the MLOD, you can get a heavy boost, or a light overdrive reminiscent of vintage microphone preamps.  the fancy thing about this circuit is the lack of coupling caps in the audio path- something usually reserved for mic pres and hifi circuits.  this lends itself to the "transparent",  uncolored sound happening here.  if you encounter any oscillation at the highest gain settings, simply raise the value of the 100 ohm resistor near the gain control to lower the amount of maximum gain. 

as always, if anyone happens to put this on the breadboard, or if it sounds like something you might want to build, let me know, and i'll whip up a layout for it.

take it easy!



here's a VERY informative video on grounding that was posted by Paul Marossy over at DIYS.  great video.  everyone should watch.



here's a cool little protocol for troubleshooting opamp circuits for the university of exeter physics department.  it should be able to get you out of most opamp entanglements you get yourself into.



here'a some interesting things i found on the ee times site.  an interesting article on audio myths, two audio amplifier design articles from john linsley hood's book, and another with a great vintage video of rca tubes being made.  very cool stuff!






national semiconductor application note number 779 is a great resource on active, passive and switched capacitor filters.  check it out!


as a bonus, here is a page on designing state variable filters for audio.




this page from the ALL ABOUT CIRCUITS website has a multitude of worksheets for the electronic diyer to learn from and test themselves with.


there is everything from AC, to DC, to FETs, opamps, filters, and BJTs.  even such simple stuff as ohm's law and caps and resistors.  seriously, everything from atoms to active circuits!

for example, here is one of their "design projects".   the objective is to help you in designing tone control circuits.


with these worksheets, there should be no excuse not to have some serious kung fu!! hiiiiiieeeyahhh!!!!


ok, here it is, as promised, AA's Circuit Splinter No.2!  but first, a little warning- i am not an electrical engineer, nor do i claim to resemble anything close to one, here or on television.  please take everything i post as just what it is- the off kilter ramblings of a misinformed diy enthusiast- nothing more, nothing less.  i'm trying to learn just like you.  


we are continuing our limited look into DC coupled buffers and amplifiers.  in this case, a JFET/BJT Feedback Amplifier.  this amplifier configuration is known as what is called a Sziklai Pair, otherwise known as a compound transistor, which is similar to a darlington pair, and sometimes called a compound darlington.  this wikipedia article goes into the sziklai pair a bit more, such as how they are often used in discrete solid state output stages. 

here is a great article as well from answers.com-

in this article is a description of the feedback involved-

and finally, a jensen transformers app-note for a piezo buffer amp-

basically, what we have done that is different here from the last edition of Circuit Splinters(in my limited understanding), is to reduce the amount of feedback from one stage to the next.  previously we had an infinite amount of feedback, which gave us a voltage gain of 0.  by inserting R5 into the picture, we raise the resistance, and therefore lower the amount of feedback.  in doing this, the gain of the stage rises.  as you can see below, the gain of this stage is equal to the ratio of R3 to R5.  so, lower R3, or raise R5, and the gain goes up.  the circuit below has R3-470, R5-4700, so 4700/470 = a gain of 10.  the great thing about this kind of stage is that you have a high input impedance from the FET, a buffered output, and you get voltage gain instead of just current gain as in a classic buffer.  remember that R2 may have to be adjusted to 1/2 your supply voltage on the drain of Q1 for the proper amount of headroom.

i think that this circuit tends to sound best when used in a "clean" gain type of stage, with just a slight amount of breakup.  never the less, many different adjustments can be made.  instead of R3, put a large bypass cap, and move R3 to the emitter of Q2 for more gain.  try different bypass caps for different frequency responses.  bypass Q2's emitter.  if you adjust your bias circuit, you can use a bjt for Q1.  try a Ge pnp for Q2.  see what happens when you put a small cap from the source of Q1 to the collector of Q2.  

here is an example of an RIAA circuit that uses this configuration.  you can see what has been done to tailor the frequency response of the stage for the RIAA curve using RC filters in the feedback section.
(click to enlarge)

here's a version from John Linsley Hood that uses a bootstrapped input-
(click to enlarge)

here's another one that uses a bjt for Q1, and has an interesting baxandall-style tone control based on feedback as well.  note the bias configuration for the BJT input transistor.
(click to enlarge)

as always, if anyone out there has any real knowledge they can share, feel free!  the sky's the limit.  go nuts.  have fun.  take it easy!  



here's more electronic theory videos, this time JFETS.



here's a few interesting audio electronics related vids i pulled off the net.  i haven't had a chance to check them out yet, but i thought it couldn't hurt to post them anyway.  check out the other videos on the channels of the posters, there is some good stuff there as well.  


gigelmargel's CRANKED AC

here is a pic of an assembled cranked ac pcb put together by FSB member gigelmargel.  looks great, and thanks for verifying the project!  the full project files can be found here-



here's number of handy electronics oriented calculators from around the web.  enjoy!

common emitter voltage divider calc
big muff bias calc
fuzz face bias calc
electronic math helper page
opamp gain calc
LED resistor calc
capacitor calculators
ohm's law calc
parallel resistance calc
transistor sim and calc
sound studio and audio calculations
capacitive reactance calculator- what's the resistance at this frequency of that cap?
electronics2000 calculators- a bunch of em!
-many calculators for amplifiers are available at Amp Books.  including these--
cathode bypass cap calc
coupling capacitor value
bright boost cap calc
grid stopper resistor calc



clicking on the title of this post will send you to a download page for the book SOLID STATE GUITAR AMPLIFIERS by TEEMU KYTTALA.  trust me, DON'T be dissuaded by the title!  even though sold state amps are kind of like kryptonite to many tone whores, this book contains tons of info that can be extremely useful when designing audio circuits.  explicitly the preamp section, which is full of heaps of goodies that can be used for stompbox design.  it's written in a simple, yet concise style that tells you just what you need without getting bogged down by too many details.  also, the power supply and power amp sections have everything that you would need to build an ss amp. this book really is a great resource that i will be diving into head first.  i believe teemu goes by teemuk on the forums, so make sure you give him a hearty thank you if you download the book!




i just thought i would post a link to ibodog's green bomb vero layout over in his diys gallery.  the layout is verified, and there are a number of other nice layouts over there, too.  click on the title of this post for the link.  thanks, ibo!



continuing right along with all things FuzzRite, an anonymous donor supplied me with a very rare Mosrite amplifier schematic to post over at FSB.  it contains a schem for the onboard FuzzRite circuit that came stock with the amplifier.  as you can see, it is a bit different than the FuzzRite schematics that we know of, kind of a mix between the Ge and Si versions, as well as having a few different values, a 220pF compensation cap on Q1, and of course the fact that it runs on 33V.  i hope you guys enjoy this rare treat!



So it's been a while since i've posted here, so i thought i'd actually post something worthwhile!  here is the first episode of Apocalypse Audio's CIRCUIT SPLINTERS.  i hope to post little circuits that can be helpful when designing your own stompboxes- like gain stages, tone controls, filters, clipping arrangements, etc.  i'll try to keep the things i post relatively new, because we all know places like geofex and amz have this kind of shit locked down, and i really don't want to post a bunch of circuits that you can find elsewhere on the more venerable stompbox sites on the net. most of the stages i'm going to present are things that i've culled from the various books and websites that i have found, and occasionally something that i have come up with or modified to my own liking.

the first circuit i am going to present is the high impedance input JFET/BJT buffer circuit below.

this is a rather common cookbook circuit that you can find in books and on the net, yet personally i have yet to see it in stompbox circles, so i thought i would post it. it uses an npn JFET DC coupled with a pnp BJT .  the FET allows a a much higher input impedance than a BJT normally would.  R1 could realistically be anything from 1M to 10M, this will only really affect the low end coupled with C1(which i have left open for you to decide the value).  the BJT is "inverted" so that a pnp transistor can be used with a negative ground circuit, for what i presume is for it's lower noise specs. i haven't measured the output current of this configuration versus a single FET buffer, but that could be something i'll do in the future and report back.  the real reason i am posting this buffer is because it can easily be turned into an amplifier stage, which can subsequently be used for a sweet booster/overdrive. all that and more in the next installment of CIRCUIT SPLINTERS!

bonus question:  anyone want to tell me where to place the resistor in order to turn this buffer into an amplifier?

here is some info from RG Keen on the circuit-



brothers and sisters! you know it's time to...

show you some pics!

my buddy Double A picked up Green Bomb No. 1 and has been putting it through it's paces lately.  he has reported back that the intense fuzz sounds garnered from this machine are indeed up to his high demands, and was kind enough to post a nice clip as well as take some pics of the this sucker for me.  (i really hafta get a camera soon!)  he started up a little myspace page that will be focusing on different pedals, and he chose the GREEN BOMB as entry number one!  check it out, there is a sweet sample of A-Double hashing out some nasty Davie Allen licks!


he was also kind enough to send me a few pics as well.  here are a couple of the best-



click on the title and you will be treated to a great clip of the GREEN BOMB FUZZ made by FSB regular ibodog. many, many thanks to Sir Dog for his excellent contribution.  it shows off many of the middle range tones of the GREEN BOMB.  hopefully, i will soon make some clips of the more extreme end of the palate as well for you all to enjoy.

thanks ibo!  you rock.  i am in your debt.



recently there was a request for a Toecutter pcb, so i made up this version of V1 because i still think that it is probably the best sounding version. it isn't verified, but it is checked in eagle, so it should be good. i hope you guys enjoy it, and be sure to let me know if you get it built!

just a little tip- for a wider variation in the gain control use a larger pot- say 500K.  personally, i like to keep it up around the upper end of the gain range, so 100-250K is usually what i like to go with.  also,  a 100K volume pot will brighten up the sound a bit, and changing the 4K7 resistor to 10K will add more gain, but i think it loses some of it's crunchy magic.


spencerpedals made this great post about The Toecutter over at FSB, i thought i should share it-

"Re: RnFR- The Toecutter
Postby SpencerPedals » Thu Feb 25, 2010 9:42 pm
Finally got around to breadboarding this with some low-leakage pirated germaniums, house numbered so I have no idea exactly what, and it will rattle your fucking skull. I've liked the clip since I heard it, but didn't have a closet full of parts. If anyone's ever heard the stuff from Slow Burn, the tones you get are almost identical. I always test pedals through an old school solid-state Crate and then if nothing explodes, I run them into my Ampeg V4. This thing definitely comes alive in the later (as most do) and with tuning dropped to C, is probably even lethal to small animals. I don't have any pets, so I can't say for sure. Actually I do have a snake and I didn't check, but she may very well have perished. I have V1.1 on the breadboard but with a 500K gain pot from V3 and used Q1 and Q2 in the 80's hFE and Q3 in the 120's. I'll be seasoning to taste over the next few days/weeks and report what I settle with. And if you're not a fan of growly loudness, it actually sounds very sixties fuzz when you turn the gain down and screw with the bias. Not my territory with this one, but versatility is there. More to come."
great stuff! glad to hear he's diggin it!



hey you slags! if anybody is actually reading this thing and getting any enjoyment, please let me know! i mean, even if nobody read it, i'd still do it for my own sake, but it sure would be nice to know that someone is getting something worth while out of this. if there is anything you'd like to see more of, bring forth your brainiac-size ideas, and i'll take them into consideration. you can also sign up to become an official follower on the lower right as well.

or maybe i'm the only one left on the planet...... just me and my robot.


my buddy jrod over at FSB turned me on to this killer vintage Russian guitar and effects site.  click on the title, and you get a babelfish translated version of the site.  i've barely gotten into it, but it looks like it's filled with some freaky psychedelic machines and cold war rock and roll ingenuity.  check it out!

he also found on the same site, a different version of the KAZAN BOOSTER that was featured in one of the first posts on APOCALYPSE AUDIO.  the difference with this one is that there are diodes sprinkled around in the signal path, which is a rather odd design technique.  the only other place i've seen something similar is in Joe Gagan's Vulcan distortion.  this can be found in the ANALOG ALCHEMY LINK on the right of the page.  he described it as a sort of limiter to prevent hard saturation of the transistors.  it sounds like a neat little trick- i might have to give it a shot sometime.


if you look over to the lower right, you'll see apocalypse audio's new freestomp rss feed.  now you can keep up with the coolest stompbox forum on  the planet at a glance.  you'll never have an excuse again to not know what's inside that new, totally original, totally awesome electra copy that yer favorite solder jockey has been working on nonstop for years before it's release. or why not get in a heated debate about the "sound" of capacitors?  it's all there.  and i mean "all"!  i'd be surprised to see a production stomp by a major manufacturer that hasn't had it's schematic and inner workings fully analyzed.  join in the fun! we don't have much time before we are all turned back into dust anyway.


click on the title and get sent to a bevy of the highest quality audio electronics books for download.  now you can use your original 75 dollar copies for kindling!  just hurry and get 'em before they decide to get their electrilives cut short by the evil horde of junkpile robots from greedtown.  



here's a tagboard layout for the GREEN BOMB that i built up today.  it's got a great deal of variation due to the wide range of gain and the phase cancellation.  lots if tones, but it always has that great FuzzRite buzz.  it's going to be a fun fuzz when i get it fully built.



here's something i was working on the other night.  it's a revved up mosrite fuzzrite based off of gus's gusrite circuit.  i basically juiced up the gain even more, did some stabilization and frequency response adjustments and added a nfb based tone control to add even more weird phase shaping possibilities than what was had in the original.  it's basically like a fuzzrite on steroids.  i'd suggest a mid gain transistor for Q1 and a high gain for Q2.  different transistors do different things, so it's worth trying out some different ones.  oh, and it can totally do that spirit in the sky thing perfect!  when you turn the gain all the way up you get that ratty almost misbiased thing that greenbaum had going on in his onboard fuzz.  back the gain off and rattyness goes away.  this thing is my new go to for crazy psych madness.  if you want more of a honky sound, lower the transistor gain a bit.  i'll probably try and do some more tweaks in the future, and i'll post them when i get a chance.

also-  i've got a tagboard layout that i'll post when i get it verified. ;]

here are the schematics from Gus's rite fuzz and the mosrite Fuzzrite for reference.  if the owners have a problem with my posting them here, i will gladly take them down.

also, i was asked on FSB to describe the added tone control.  i tried to explain it to the best of my ability.  if anyone has anything to add, please, feel free.

the fuzz control on the fuzzrite works by adding the output of the first stage, an out of phase signal, with the output of the second stage, in phase signal.  this is what produces some of the thin, hollowed out, phase cancelled sounds that the fuzzrite is known for.  the shape control takes the non-inverted output of the first stage, with the output of the second stage, which also gets mixed in with the output of the first stage with the fuzz control.  the shape control has a low pass filter due to the .01 cap to ground, so when when it's negative feedback takes place, it only cancels out the lower frequencies and leaves the highs.  with this control you are still able to get the brite, zippy sounds of the original fuzzrite, but are now also able to get the thicker sounds of gus's ritefuzz- all through the same negative feedback techniques similar to what was used in the original fuzzrite!  



click on the title of this post, and you'll get directed to part of the excellent Fun With Transistors Page on amplifier feedback. feedback can be used to increase linearity of the output, curing oscillation, reducing gain, and tonal shaping among other things when used in amplifier stages. usually when we speak about feedback, we are talking about negative feedback in amplifiers. this is accomplished by adding an out of phase signal to the input of a gain stage, often by taking the output of an inverting amplifier. the webpage takes an in depth look at different types of feedback complete with diagrams and equations for those that are so inclined. check out the rest of the site as well as the Fun With Tubes page which has some great info, too.


if you click on the title of this post, you'll get directed to the instructions page of a cool little circuit simulator program. while i doubt that this this is nearly as in depth or accurate as something like the SPICE-based programs out there, it's a fun little program that runs on JAVA, and it can definitely help the learning process along. not too mention, it is much easier to learn. there are a number of circuits that have already been put together that you can easily adjust and add to as much as you like, or of course you can start from scratch. i had a lot of fun messing around with a gain stage that i have been trying out as of late, seeing how the output changes with component values. it's a lot of fun, and is a great learning experience as well.


HERE is a page from Paul Marossy's website with a number of downloadable chapters from this great book by Jack Darr. there is lots of info, including tube and early solid state, that is guaranteed to be helpful for anyone out there looking to get into this of thing. check it out, it's an excellent book!


i recently decided to start monkeying around with some tube amps that i have aquired over the years, namely a couple of bogens, a bell pa head, a couple of small voice of music phono amps, and my big ol traynor yba-3.  a great gadget that is a must have for beginning tube amp tweakers is the Lamp Limiter.  it allows you to power up the amp while being able to tell if the amplifier is drawing too much current off of the mains.  if there is a short in the amp, the lamp will light up brightly.  here is a nice article from a UK radio sight about the lamp limiter, and a cool thread about "reading" the action of the bulb.


these UK articles recommend a 100w bulb, where as this article from R.G Keen says that a 25w or larger bulb will do.

a lamp limiter is a great way to help the learning process when working on tube gear, and hopefully can keep you from needlessly blowing anything up!



jrod over at FSB is planning on building a DIRTY BOOTS, and asked me what kind of tweaks could be made.  it's really a highly variable circuit, and can be tailored to your specific tone very easily.  here's what i wrote to him-

there is a lot of tweaking that can be done to the DB.  you might want to lower the collector resistor on Q2 as it is a bit voltage starved.  if you want less drive, increase the resistor in between stages, or take out the bypass caps on the emitters.  also, you might want to increase the collector resistor on Q2 as it is kicking out pretty much full gain, and that can make it a bit noisy.  maybe try 1K.  it all depends on what you want.  if you want it brighter, lower the value of the compensation cap from C to B on Q1 or put a 47K resistor in series with the input.  adjust the in and out caps for low end.  it's a really easy circuit to tweak, so i would just put it on the breadboard, and figure out what you like for your amp.



a while back, i posted this little article on a couple of fuzz circuits i found on the triode electronics site. the first is very similar to a fuzz face style circuit, where as the second is a little bit different. it has what appears to be an emitter follower into a kind of dc coupled complementary gain stage pair. very much similar to the jordan bosstone. here is a link to the original article.


while surfing around the voluminous pages of Jack Orman's AMZ effects website, i saw something that looked a little familiar.

it seems that the triode fuzz and the amz sixties style fuzz are one in the same!  most likely, this is an old circuit taken from one of the many electronics "cookbooks" from back in the day.  regardless, i've heard from a good source that it's supposed to be a great sounding circuit, so i decided to draw up a layout- this time for tagboard construction.  tagboard, eyelet board, or turret board can be a fun way to do your circuit board construction for a change.  there is no etching or drilling to be done, and you get to use those nice sounding axial foil caps that would've never fit on your pcb circuit.  i really like using this particular tagboard that can be found at weber as well as apex jr. for very reasonable prices.

it has 3 different solder points per tag that makes it very easy to find holes for your passives, actives, and wire without running out of space.  the layout i made for the triode/sixties fuzz circuit was made specifically for this type of board, but you could easily adapt it to other types of tagboard out there.  i haven't built it yet, but i do plan to in the near future.  as always, let me know if you decide to build it yourself.

i got this thing on the breadboard, and had a rough time getting it to bias properly.  i'm going to try and figure it out, and i'll post anything i find.

due to problems with this circuit biasing correctly, i have pulled the layout.  i'll post a new tagboard layout for a better design shortly.  looking at this one with a more informed set of eyes, there are many things that could be done differently to make this a better design.  i'll post another tagboard layout for a proper fuzz circuit once i get it checked and verified.