THE DUMMIES GUIDE TO DIRT PEDAL TECH
GERMANIUM TRANSISTOR
In 1947, (the year I was born) Walter Brattain and John Bardeen invented first transistor made from germanium crystal. It did the same job as a tube. Small, it didn't burn out or break like a tube and was relatively very cheap to make. The transistor is probably the most important invention in the whole of the 20th century. No transistors NO smartphone, Laptops's no anything, lol.
The Fuzz is the first dirt pedal. Basically to over simplify you can run one transistor into the other and overload the circuit and distort the crap out of a guitar signal, lol.
The basic sound is warm and grainy. Not a lot of clarity.
SILICON TRANSISTOR
In 1954 Morris Tanenbaum invented the silicon transistor.
It did not leak like the germanium transistors, it was much easier to make consistently the same with not a lot of waste etc. So that made it cheaper then a germanium.
The basic sound is bright and tighter than a germanium. Reliable and problem free. They can get ice picky.
MOSFET TRANSISTORS
In 1959 Dawan Kahang invented the MOSFET transistor. For us the big deal about it is it sounds, very, very close to a tube. So if you clone a guitar tube amps preamp section replacing the 12Ax7 tubes with FETS you just might create a convincing MIAB. Yes? WTF!!! YES!!!
They sound like a tube but a just a bit less smooth, sweet or rich.
THE DREADED OP-AMP
In 1967 Karel D. Sharzel invented the OpAmp. All transistors increase the level of the incoming signal. The big deal with the opamp is they are in comparison like tiny clean sounding preamps totally finished and built into a miniature box and stupidly dirt cheap to make.
They depend primarily on the diodes put after them for their basic dirt sound so they vary a lot. They lend themselves to simple cheap to make pedals so they are virtually always used on crap pedals and naturally get associated with amateur sounds. They need not be. The best OpAmps can sound virtually transparent.
WHAT'S THE DIFFERENCE
The big deal for us is that with tubes you have to string them together and make a preamp to increase the the level of the PU signal and shape and colour the sound. With transistors it can be smaller but it is the same deal. With an OpAmp it is already done in the chip. Like anything electronic even the the clean sounds are NOT clean. They have distortion even if it is perhaps just 5%. It is either a pleasant colorization or an unpleasant one. I would describe an OpAmp as having a mild but perceivable strident metallic clean tone.
WTF!!! We love the 'type' of distortion a tube makes and with good design a MOSFET will clone that. Soooo.... the best and most pricey pedals use them to make an Amp-in-a-Box.
With an OpAmp it is already loud (for its size) signal so if we put the signal thru diode which is like a funnel with lots in and less out we F.up the signal and it distorts.
THE BAD NEWS
OpAmp pedals are their own thing and with careful design and a really good tone control circuit can be shaped to deceive the ears that they are tubes as well but it is easier to do with high gain because that much distortion disguises a lot. The Rat is the best example of a good use of an OpAmp.
The thing that gets up my nose is they are cheap to make and the whole design is not rocket science so they are, or after reading this 'were' easy to sell to you as some complex wonder box for big money.
The Tube Screamer variation has a genius simplicity to it. Because of this you can take it, ...F. around with the diodes even by trial and era as a beginner and come up with some cool sounds. Great ...but it is a F.ing Tube Screamer! Skip the con job and price gouge!!! WTF!!!!
THE GOOD NEWS
OpAmps can make some very cool noise and we all own them already because they are cheap. Even a Klon is an OpAmp distortion. For me personally even though it cost bigger money I feel a really good sounding FET distortion by cloning a tube amp circuit blows even a real Klon out of the water in two seconds then leaves to go for lunch. Bit WTF I love my Fuzz pedals and my Rat too, LOL.😊
So enough of my pontification lets let ol' Josh Scott take us on a trip thru Op-Ampville.
1970's OpAmp Distortion