E EURO TRANSISTOR INFO

FSB member kindafuzzy posted this link to the forum today. it has some valuable transistor info on some of the eastern European transistors you can find on eBay. included are the NPN Ge 10XNU71, and the MP14 that I use in many of my circuits. these transistors are still easily found, and don't demand the crazy prices of western euro trannies.

LINK.

DIRTY BOOTS V6

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.

DIRTY BOOTS TRANSISTOR OPTIONS

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!!

THE GERMANIUM REVIVAL

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!

LINK

H-FUZZ

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!

FOUR HORSEMEN OVERDRIVE

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.

http://freestompboxes.org/viewtopic.php?f=28&t=11745

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.

DIRTY BOOTS SOUND CLIP

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!

MILITARY DIRTY BOOTS PICS

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.

ELECTRONICS CALCULATORS

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


common emitter voltage divider calc
http://www.diystompboxes.com/biascalc/vdbias.html
big muff bias calc
http://www.diystompboxes.com/biascalc/bmbias.html
fuzz face bias calc
http://www.diystompboxes.com/biascalc/ffbias.html
electronic math helper page
http://www.diystompboxes.com/analogalchemy/emh/emh.html
opamp gain calc
http://www.csgnetwork.com/opampcalc.html
LED resistor calc
http://www.csgnetwork.com/ledsingresistancecalc.html
capacitor calculators
http://www.csgnetwork.com/capacitorinfoconverters.html
ohm's law calc
http://www.csgnetwork.com/ohmslaw.html
parallel resistance calc
http://www.csgnetwork.com/parallelresistcalc.html
transistor sim and calc
http://www.csgnetwork.com/transistorcalc.html
sound studio and audio calculations
http://www.sengpielaudio.com/Calculations03.htm
capacitive reactance calculator- what's the resistance at this frequency of that cap?
http://www.electronics2000.co.uk/calc/reactance-calculator.php
electronics2000 calculators- a bunch of em!
http://www.electronics2000.co.uk/calc/
-many calculators for amplifiers are available at Amp Books.  including these--
cathode bypass cap calc
http://www.ampbooks.com/home/amplifier-calculators/cathode-capacitor/
coupling capacitor value
http://www.ampbooks.com/home/amplifier-calculators/coupling-capacitor/
bright boost cap calc
http://www.ampbooks.com/home/amplifier-calculators/bright-boost/
grid stopper resistor calc
http://www.ampbooks.com/home/amplifier-calculators/grid-stopper/

TOECUTTER V.1 REV.C PCB LAYOUT

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!

XXXXXXXUPDATEXXXXXXXX
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.

XXXXXXXXXXXXXXXXXXXXXUPDATEXXXXXXXXXXXXXXXXXXXXXXX

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

"Re: RnFR- The Toecutter

by 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!

DIRTY BOOTS TWEAKS

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.

ELEKTRATONE'S DIRTY BOOTS

FSB forumite elektratone built up this cool rust finished version of the dirty boots a while ago.  i thought it was about time he got some fame on the blog.  it definitely looks like this thing's been through the apocalypse and back!

APOCALYPSE AUDIO - PANZER FUZZ

my latest creation is an uber-high gain fuzz-tortion designed around the soviet GT308B germanium transistor. since this seems like one of the more common russian germanium transistors that people buy, i thought it would be a good candidate to include in my next project. the 308B has a gain that usually hovers around 75 in most specimens that i have seen, except for some batches marked with red dots that have a gain of around 20 points less on the Hfe reading. as with most other soviet Ge's, their leakage is pretty much nil, this allows for excellent stablilty, easy biasing without trimpots, and no need to do tedious gain/leakage checks. i thought the 308 would be the perfect candidate to design a high gain fuzz around because of it's relatively high gain compared to other russian Ge's, and i haven't done anything along those lines since the Toecutter, which although it is doomy as hell, it is in itself not all that terribly high gain anyway.

the controls of this guy are as follows- gain, lo drive, hi drive, tone, and volume. the lo drive control is basically a full range gain control for the 2nd stage, and the hi drive control is i gain control for the 3rd stage that is concentrated only on the high frequencies. with all of the gain and drive controls turned up, you get an all out doomy grind with plenty of bite for on the top end. rolling back the gain control gives you a great crunch tone that i would describe as medium-high gain. the tone control is a heavily modified version of one that i saw on the AMZ site. i added 2 more caps, and adjusted all of the values for a nice even sweep. turning it all the way up also brings in a little bit of low end as well, so you get what sounds like a little dip in the midrange, too- adding to the metal tone of circuit. don't get me wrong though- this isn't one of those ultra-scooped metal zone P.O.S.'s. this thing has a ton of low end and has been tuned to have a bump in the high mids as well in order to cut through the mix and add some nice grind to the tone.

i did this write up of the basics of the schematic for culturejam's new circuit design forum circuitworkshop.com.
it can be found HERE.

the input cap(.033) was chosen to roll off just the bottom end of the input signal, there will be plenty more of that to come. the first stage is a basic booster using feedback biasing(1M resistor), and a .47 uF bypass cap for more gain throughout the full frequency range of the guitar. the emitter resistor(1K) was chosen to limit the amount of output from the first stage, and the 470pF cap rolls off some highs and stabilizes any oscillations that might happen.. next we have the gain pot(500K) and a 2K2 resistor setting the minimum amount gain available. the .01/220K combo allows highs to pass easier than lows trimming some of the fat off of the boosted signal. stage 2 is biased the same, as is stage 3. i find this technique of biasing easy and simple, allowing for fewer components as well. the .047uF cap rolls some high end off of this stage. the lo drive pot is a 10k pot going through a 47uF cap to ground. this isn't really just low end getting boosted per se, more of a full range gain control for this stage, but with the lows rolled off by the .o47 cap it definitely has some of that feel to it. the 100K/.1uF combo are doing negative feedback duty, reducing the overall gain a bit, as well as taming some noise and adding stability. next, the .0047 cap is more low pass filtering, and the .068 is hi pass,interstage coupling, and DC blocking. stage 3 also has some more high end filtering grom the .0022 cap to the 9V rail, and the bias values have been tweaked by ear a little. the hi drive pot is a 1K connected to ground through a 100uH inductor. turning this up adds a decent amount of sizzle to the sound. the 680/.1uF to ground were added to round out the frequency response of this stage a bit. the tone control is a tweaked version of jack orman's swtc2. i changed some values and added the .0033 and .01 cap to ground. the final .001 cap is rolling off a bit more of the very top end. finally the volume control has a 2K2 resistor to ground to limit it's lowest value. the mosfet and 1M resistor are there for reverse polarity protection, and the 100uF cap is for power filtering.

attached is a pcb layout, that is of yet unverified, but it has been checked in eagle, so it should be good. i'm going to try and get some clips done soon- they won't be the highest of quality though, but you should be able to get the idea of what is going on. hope someone out there can give this one a shot- it's really a killer!


XXXXXXUPDATEXXXXXX  it looks like the size printed on the layout is a bit small.  if you measure it out to that size, then increase by 10% you'll be perfect.  sorry about that!

2, NO, 3! NEW DIRTY BOOTS VEROS!

dudes! made up a few new veros for the db. the first one is a small layout for box caps and radial electros for you guys that like those little baby boxes. the second one is for axial caps vintage style and specifies the specific type of caps that i have been using for my builds. of course, sprinkle your mojo to taste. i'm callin this on v5.2 because of the added reverse polarity protection diode as well as a limiting resistor for the pre control. haven't decided at the exact value for that one, most likely around 50-100K, or just put lug one straight to ground like before. the third one is just stupid small. i call it rev2. good luck you masochists! take er easy!

DIRTY BOOTS GERMANIUM OVERDRIVE

this little circuit is really what got me started in the whole DIY effects design process. i needed something that i could use to dirty up a loud, clean amp just enough to where it would have a touch of grit. it's a great little overdrive that can be used as a germanium booster as well as a fuzz if your pickups are hot enough.

it all started when i decided to breadboard the Trotsky Drive by Beavis Audio, which is basically a GE version of the Electra Distortion with a bias adjustment pot. using a russian GT313A transistor, i was fooling around with it, messing with values and such, when i remembered that the Bazz Fuss uses a diode in the C to B position instead of a resistor like the Trotsky/Electra. so i tried it out, and i got an excellently biased gain stage with just a bit of compression. then i realized that the circuit i was working on was PNP, where the BF is NPN. so the diode configuration is actually reversed. eventually i came to learn, with the help of many generous folks in the DIY community, that the GE diode that i was using was leaky, all of them are leaky, and it is this leakage that is actually acting as a large resistor and biasing the transistor. cool,huh? along with that, i'm sure that the diode is adding it's own little stamp on the situation with a bit of compression an break up.

after messing about with a ton of diodes this way and that, with filtering, in series, etc., i decided that i'm just not that big of a fan of diode clippers. i find them unnatural sounding, and their clipping just sound too "obvious" to me for some reason. so i ditched the clippers, added a small cap from C to B to roll off a bit of highs, and just put a whole nother stage in series with the first.

Lo! the Dirty Boots was born.

eventually i ended up trying a bias pot on the second stage and some different switching options for changing gain and tone, etc., but ended up with a normal emmitter controlled gain stage, a pregain control, and a volume pot. the latest mod was the series resistance between stages and ditching the cap from C to B on the second stage to open it up a bit.

it's really a great sounding little circuit using ge trannies which can be found on the bay for dirt cheap. the basic gain stage can be used for other things as well- it became the basis for The Toecutter.


give it a try sometime, or i'll send my band of mutated hobbit rat people to dig you out of your bomb shelter and eat you for second breakfast.

the thread at FSB about the Dirty Boots can be found HERE.

many thanks go out to Martin Chittum, Marcelo "Mac" Tripodi, and others that helped me understand along the way!



here is a layout using common sized parts. i have another for use with the extra mojo axial caps and such that i will post later.





daniel zink made this great version of the Dirty Boots in a Hammond 1590A box. a little killer!







here's another one from mr. zink- very stylish!