Mesa Boogie’s transparent overdrive, full of sustain and rich in harmonics, delivers +20db of clean boost. Great for pushing your high gain amplifier or as a standalone overdrive in front of a clean channel. This circuit features a Baxendall eq, and its architecture reminds us of TS808.
As a general rule, every great high gain amplifier needs a nice overdrive in front of it to push it up and tight the tone. Mesa Boogie is not an exception to the rule; that’s why they developed their own TS-inspired overdrive to plug it, whether into a clean amp channel as a stand-alone overdrive or especially to enhance a crunch or higher gain channel.
This mid-gain overdrive is a highly flexible and adjustable overdrive with sufficient gain for fluent leads that will enhance rich harmonics and overtones, all featuring the distinctive Mesa character.
Even though this pedal is labeled as transparent overdrive, it has enough Mesa flavor to pump up your Marshall or fender amps. Also, it matches perfectly with other Mesa amps or pedals, like with the Mr boogie and Rectifier Box. We tried them and loved them both.
One of this circuit’s high lights is its Baxandall EQ that allows you to shape your tone by the treble and bass controls, an incremental improvement over the classic tone control of the TS808 models.
This circuit includes a Baxandall eq with Bass and Treble controls, making out of this pedal a truly tone-shaping device, being this a great improvement over most TS808 tone stacks.
These circuits initially call for 2SC1815 NPN silicon transistors for the input and output buffer, which might be a bit hard to source. However, you can easily replace them for more common 2n3904, 2n5088; don’t forget that this PCB has been designed for 2SC1815 transistors with ECB pinout replacements such as 2n5088 are normally EBC.
We have attached a pic below of how to place a replacement transistor.
For further analysis on this circuit take a look at this thread on Free Stomp Boxes Forum.