Reinhold’s Red Skull

Project overview

High gain JFET amp in a box. This circuit recreates the tone of Bogner Ecstacy’s Red channel tube amp incorporating many elements of GoosoniqueWorx Seventheaven. The Bogner Red channel pedal does not directly inspire this project, but we can assure you it will melt your face off.

Introduction

If you have been following PCB Mania for a while, you know we love Amp in box pedals, whether based on big brand models, like the Freeman or Benzin VH4, or DIY versions of classic tube amps like The Wolfgang and the JCM800. For this case, we have something Hybrid in between both worlds. This DIY circuit mixes elements from a direct JFET conversion of a tube amp with features from the original Bogner Red pedal and GoosoniqueWorx Seventheaven. We also included a dual-channel option with independent volume knobs and different gain structures.

This pedal features an internal charge pump that allows you to change your voltage input from 9v to 18v just with the flick of a switch. Just bear in mind to dial the proper biasing that works the best in both conditions, or try your favorite settings and let them fixed.

The EQ section recreates the passive tone stack of a tube amplifier, while the PRE-EQ toggle enables capacitors after the first gain stage to thick your sound from the beginning of the signal.

Structure toggle changes the gain’s dynamics; however, it could get a bit too nasty under certain bias conditions.

One thing is for sure about this model, if you like High gain, chugga chugga, and preamp in a box, you will love the Red Skull!

Remember, this project uses JFET, which requires proper biasing through their respective trimpots.

This board allows you to use either SMD or standard through-hole JFET.

Controls

• Bass
• Gain
• Mids
• Presence
• Treble
• Volume
• Volume 1

For further analysis on this circuit, take a look at this thread on Free Stomp Boxes Forum.

For anything technical questions regarding this build, don’t forget to check out our Facebook Group and our forum at Free Stomp Boxes.

Red Skull 1.1v – Building docs

Red Skull – Building Docs

Red Skull – Drilling Template