Kick your playing into high gear with this Impressive 20 dB of completely clean boost that makes your core tone shine through. A really straightforward project, easy to build, easy to play with!
The Atomic boost is based on the TC Electronics Spark ™ a perfect one knob beginner project to check if you are into DIY. Perfectly suited to add some extra gain to your Leads or to get Crunch/driven sounds out of your semi-dirty amp. Especially when your amp tempts to be a little too dark, the nuance of brightness it adds can be very handy without making the signal harsh.
There are plenty of equivalents and similar-sounding transistors, so I would recommend using dip sockets and start diving into creating your very own tone.
For instance, you can use Q1-4 – BC547 (type a-b-c the higher the letter, the more gains they are) and for Q5 a – BC557C (flip it 180 degrees to the silkscreen!)
2n3906* PNP transistor. Although the original unit presents a BC558c transistor, we have experienced better results with the listed 2n3906. You can still experiment with BC558c just by flipping the transistor 180 degrees. A higher gain direct replacement could be 2N5087.
BC549c** NPN transistor. You can try 2N3904, 2N5088, 2N5089 replacement; take in mind you need to flip the transistor 180 degrees to the silkscreen. The order listed is from lower to higher gain.
For further analysis on this circuit, take a look at this thread on Free Stomp Boxes Forum.