Back And Forth

A subminiature tube tremolo pedal using the 5672. It adds quite a bit of boost and "grit" to your tone as well but still makes for a great effect. It lays somewhere in-between Tremolo and Vibrato. A very similar sound as the Bigfoot Magnavibe, for a modern reference. Rick Holt/Frequency Central posted the schematic on a forum somewhere deep in the mid to late 2000s and this is a part for part layout of that original schem.

 

PenToad +

Similar to the "Pentoad" boost circuit, but this version introduces 1N60 diodes to clip the signal. Having the gain turned down will give you the sound and feel of the original pentoad circuit, whilst doing the opposite gives you a mid gain overdrive type sound. Cranking the gain knob will get you into fuzz territory. For my personal build I put two of these exact circuits in series in a single enclosure, gets really fuzzy that way. It should be noted that while the 5678 will work in the original, it will NOT work in the "+" version.

PenToad

A subminiature vacuum tube boost circuit. These little tubes are called 'pentodes' and are highly microphonic so be prepared. Original schematic was made by Frequency Central's Rick Holt and can be found on various archival forums. Its a really nice "warm" tube sounding boost and breaks up the monotony of another Valvecaster. I have another layout based around the same schematic but introduces some clipping diodes and gets pretty raunchy, appropriately called the "PenToad +".