The Dinosaural OPA-101 Overdirven preamp is a variation (or improvement) on the Dinosaural Tube Bender.  

This is has the tone control like the the Aion FX version, but I did leave the output stage as a buffer as per the original.  The filter itself is on the original which you can see on the schematic / tracing journal.  Well worth a read as there’s a lot of really useful background information on this pedal.

There’s also the option to run this true, or buffered bypass.  Personally I’d run buffered, but that’s just me.  

DINOSAURAL OPA-101 OVERDRIVEN PREAMP – VERO LAYOUT