The Lemon Rockververb is an exclusive original design by PCB Mania, Inspired on Orange Rockerverb, replacing the tubes for JFET in order to make it pedal-friendly.
The orange rockerverb was originally developed for over a decade and released by 2004 as the first high gain tube head by the British company in response to the need for extra gain from the modern players. But that doesn’t make this marvelous preamp exclusively valuable for metal players, this bad boy is a truly versatile workhorse that will take you anywhere from classic British crunch to the very heaviest in modern metal.
Remember this project requires sourcing some good quality JFET from trusted sources for proper functioning. We always recommend using SMD JFET as their reliability is far superior to the discontinued through-hole counterpart. Also bear in mind this project requires bias the transistors correctly with the respective trim pots.
To do this correctly, plug the pedal into your 9v power supply/battery, grab your multimeter and plug the black terminal into any ground of the circuit, while with the read touch the Drain legs of your transistors if it’s done correctly should appear how much voltage is receiving that leg.
Now turn the trimpot with a screwdriver till you can read 4.5v- or half of your power supply, in caser you are using 18v- on the screen of your multimeter. Repeat this process with all transistors and their respective trimpots till all of them are measuring 4.5v, then proceed to do fine-tuning by ear on what you hear are the best settings of each transistor.
Don’t forget to share your favorite bias settings and pictures of your build on our Facebook group!
For further analysis on this circuit take a look at this thread on Free Stomp Boxes Forum.