This one has been requested for a while. There seem to be several versions of this circuit so I guess we should start with V1? There is several schematics online, all of them have different wiring for the Bass and Treble controls. So the lug numbering may need some corrections.
The stock Rumble Fuzz suffered from not being loud enough. Dead End Fx decided to take care of that and added a J FET booster after the Volume control (it is labelled "Fuzz", not sure why....).
The layout below is verified and this is now a loud, hairy, air moving fuzz indeed. I used a BC109C (hfe 650) for Q1 and a metal can 2N2222A (hfe 200) for Q2.
Had an unverified layout in the library that I was quite unhappy with so I decidied to give it another go with a new one from scratch. This is a soft clipping overdrive with a bass boost and cut filter. The eq / filter section are pretty unique with an OTA LM13700. With the Depth switch you can select between a simple one pole filer, a two pole filter and a resonant two pole filter. The Initial control lets you blend the clean overdive signal with the filtered signal.
Schematic from the wizards at Deadend Fx
A bit hesistant to upload this one since there is an unknown cap value and pot value. But a quite a few people have requested this one so I guess a 95% accurate trace is ok?
Traced by evilarsen, AlexS and myself. It is a Rat based circuit running on 9v/-9v up to 18v/-18v. It is intended for bass but works equally well for heavy down tuned guitar playing. Tonestack is a passive James variant and there is an extra gain/makeup stage before the output.
The diode selector rotary switch has a quite interesting configuration. Many of the diodes are stacked and are asymmetric. Probably the keep an even output level across the switching range?
A forgotten and quite odd one from the early days of EHX.
Despite being marketed as a "Microphone Echo" and having "Echo" as one of the labels for the controls, this is actually a tremolo circuit with some quirks. There is no "Depth" control as in most tremolo effects, instead there are the "Echo" control which adjust the output level for the LFO signal. "Volume" control adjust the clean signal. "Speed" adjust the LFO rate.
The schematic is redrawn from a factory schematic dated 1972. Some odd resistor values but I'm pretty sure closest common value will work. Also, the transistors is the same as in Triangle/early Rams Head Big Muffs. They are quite hard to source and Hfe is all over the place. 2N2222's or 2N3904 might be good subs.
Not much info on the web on this one but there is a short writeup HERE.
A simple and nasty octave up fuzz based on Tim Escobedos Push Me Push You fuzz. But here, the input transistor is replaced with a LM386 audio amplifier for more gain that pushes the transistors harder. Also, there is also a simple treble cut tone control added.
Based on the Green Citrus Matamp amp emulator circuit but it have enough value changes to warrant its own layout. Based on a schematic from Dead End Fx.
Time to dust off the depletion mode MOSFETs in the bin. Here is a quite interesting design using four of these overlooked transistors. It is basically Plexi voiced a low to medium gain overdrive with a James tonestack.
Each MOSFET have a3,3k resistors at its Source and according to the schematic these should be adjusted until you get 6-7 DC V at each transistors Drain so I replaced the 3,3k resistors with 5k trimpots,
Demo, schematic and writeup by the creator jonn.reckless at DIYSB.
Here is a very interesting and not overly complicated PT2399 based circuit from Bluff Chill Devices. It is an "envelope modulated delay" which sort of emulates a worn out tape delay.
This layout is for V1 only but there is two layouts; one for stock 2 knob version and one modified 4 knob version. See details for the latter further down of this post
First up the schematic and a writeup about possible mods at the Bluff Chill blog.
And the modified version with added Mix and Realese controls. Note that pot values and lug connections isn't mentioned in the blog post so some tweaking is necessary to get satisfying results. I added the values that "should" work...
*Edit* Jordan verified the modified layout bellow and tested pot values and tapers.
Later versions also had a feedback control and an improved blend circuit but there is no schematic avaiable for it on the web...
A request by KG who also provided lots of useful information and a schematics for this. A bit more simple version of the DIYRE Tape Saturator circuit using op amps and there is no need for a rack circuitry.
The circuit is supposed to run on 16v / -16v so there is an onboard bipolar voltage doubler although it only gives out around 15v /-15v but it is close enough.
Info about the circuit HERE.
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This was a request and offers something quite different.... it is a tape syle diode compressor. Notice that it runs on 16v biploar power so if you want to power it with normal 9v, a bipolar volatge doubler daughterboard can be used.
*Edit* 270421. Now verified and I got some reports it works perfectly fine using a simple FET Booster up front.
Schematic and info is avaiable HERE.
Andy at the most excellent layout and resource blog Vero & Point-2-Point Layouts traced this interesting tonebender variant a few months ago. It is a tweaked Tonebender Mk. III/IV with an input cap blend control and a Big Muff tonestack with odd values. Schematic and tracing jornal is avaiable HERE.
*EDIT 220429* Andy discovered a mistake in the trace regarding the function of the Balance control. Layout is updated. LINK
A 3 band parametric eq from the Soviet Union, anyone? Electronic switching is removed and op amp is altered for normal 8 pin DIP package which replaces the odd dual op amp 14 pin DIP package.
As for R28 which is connecting across the output of the last op amp and ground, the schematic simply says "100". Could be iether 100 ohm or 100k but 100 ohm seems a bit low?
