Tuesday, November 15, 2022

Back to the Beginning - Revisiting the Tone Geek Valve Screamer

The first guitar pedal I built (that worked - I'd attempted a Ceriatone Centura as my first build, but debugging that took a while!) was a Tone Geek Valve Screamer. It was probably a bit ambitious for an early build, but I've always been sort of a dive in with both feet kind of guy. I used the Tayda recommended BOM for the pedal, and it even came with a faceplate for the enclosure. As this original build pretty much took up permanent residence on my pedal board, I figured much like the BMP it was high time to develop a true "Steggo" version of the pedal.


The pedal itself is a modified Ibanez TS10 tube screamer. Per the Tone Geek's page, the Valve Screamer:
  • 1S1588 clipping diode mode just like the original
  • LED high headroom clipping mode for fast response and low gain
  • Keeley BD-2 style clipping mode for asymmetrical clipping for a tube-like response 
  • 3 bass selection modes for stock, bass+, and bass++
  • 2SC1815 and 2SK118 transistors per the original 
For this built, rather than going with the Tayda BOM, I worked to come up with something reasonably equivalent through Mouser. As you can see, the design uses all carbon film resistors, and I tried to match the type and voltage for the capacitors across the board including a couple of bipolar electrolytic as well as tantalum capacitors. As per the original BOM, the pedal uses 2SK118 and 2SC1815 transistors.


The enclosure wiring follows my normal process of using a star ground on the input and heat shrink on all of the jack connections. This particular build uses a stereo jack for the input because I repurposed a couple of jacks from another test project (no reason to waste Switchcraft jacks - they're expensive!). As always, the board quality was great and everything lined up well (as I'd used the original Tone Geek Tayda drill template). 


For the enclosure, I needed something dinosaur related, and as the Tone Geek version was the "Valve Screamer" - I decided to go with a dinosaur starting with v, and what better example than the velociraptor? Made famous by the first Jurassic Park film (though based on their size, the raptors in the film were closer to the Utahraptor), current scientific evidence indicates that the velociraptor was actually feathered. My lovely wife once again painted the dinosaur for this one, and since it was feathered she thought it would be fun to give it a feather color pattern like a bald eagle, and we sort of went crazy with the enclosure from there!

The sound of the pedal is amazing so far. It is at least as good, if not better, than the original one I built. I've only run it through my solid state Boss Katana amp so far, and I really need to get it running on the tube amp to investigate what tonal differences it has from my first build. 

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