Another old circuit have been under the axe, Jordan Bosstone. An attempt to fatten things up a bit and use a bass gyrator control. Wanted to try out the setup that DOD used in 90's and ended up with the tonestack from the infamous DOD FX69 Grunge...hence the name of the circuit. Not sure if it captures the Seattle sound but it sure sounds quite heavy and scuzzy.
MTK have done some great work on the BAJA 5150 OD circuit to squeeze more gain out of it.
And a short video clip. stock settings in the first 20 seconds, after that, the modded settings.
An old school, loud, dirty and sometimes noisy compressor that seems to be inspired by Roland Sustainer. The original runs on two 9v batteries for 18v operation so I included an onboard voltage doubler. It might be a good idea to socket both the LED and LDR to fine tune the the compression.
This one is my favorite clean boost of all time and it is lifted from the obscure forgotten 3 knob Fender Blender. This rare bird had four tone settings; a great clean and poweful J FET based boost and three weak fuzz settings.
The 2N5925 FET might be a bit hard to source but a 2N5457 sounds identical to my damaged ears. And while the original had a 50k pot this layout has 100kA for even more boost.
Schematic and info HERE
It is obviously based on Colorsound Overdriver/Power Boost but with quite alot mods and addons. First there is two input buffers before a heavily modified Overdriver circuit. And at last there is an op amp recovery stage.
With onboard input buffer. The original had two LM741s but these is replaced with its dual op amp equivalent 1458 to keep the board reasonably small
Last layout for a while. This is sort of a hack job, combining a Rat tuned for more low end with a LED/silicon diodes clipping switch. Then the signal is splitted into two signal paths using the Mid Scoop and Mid Boost tone sections from Boss FZ2. Signal is then fed into a treble cut control and an output buffer.
*Update 200909*
Tweaked it a bit more. A cap to ground at the input solved some noise artifacts without altering the overall sound. Highs control is now a 50kC pot.
Oh, and the name was changed to Dronestortion since....it can do some drone metal.
*Update 200912*
Final update, I promise.
The LED clippers seemed to the driving the following eq op amp stages into clipping resulting in some crackle and a bit harsch decay. Replaced those with normal 1N4148's and for the lower threshold diodes I used germanium diodes, old soviet D9K's but any ge diode will do with V.d. 0,3-0,27.
An obscure old japanese ovedrive circuit that looks like your worst 80's metal pedal. But the reputation is pretty good and it has its small fanbase. And it is not a YATS.
Found this cool little thing at DIYSB. A fairly simple high gain circuit which is supposed to emulate a cranked Marshall using three MOSFETS with a J FET buffer up front. There is a simple treble roll of at the end of the circuit.
Write-up, schematic and a demo HERE
Harmonic Percolator is one the coolest vintage dirtboxes out there with its simple yet unique design, its odd even order harmonics texture, odd mojo parts and it is also a very good overdrive with the gain control rolled back.
But using mostly humbucker equipped guitars nowadays it tend to be overly compressed and a bit muddy and dull. Started to tinker with it tso it would suit hot humbuckers but no dice. As it is an unique circuit like no other, the usual mods didn't work out very well like reducing input cap or add a resistor in line with the input signal.
But I stumpled upon Dead End Fx Splinter project whcih offers a sollution for this namely reducing the coupling cap value between the transistors and adding a cap across the base of Q1 and ground.
Later on I added a "Texture" control which techically is a resostat which alters the resistanse to ground for one of the clipping diodes. Most stock HP's has 4,7k resistor here for some assymetric clipping. I used a 10k pot so stock setting is at noon, turn it up and you get a more open and wide distortion, roll it back for some glithy compreesed sounds with sub octaves jumping around.
And I added a two band gyrator tonestack at the end with values not to far away from Boss HM2. The result is a quite lo-fi, fat, industrial and grim fuzz.
