You’ll have to decide for yourself whether you want to jumper C10 on your cream board BJr.If it’s the only mod you do, I don’t think you’ll hear much difference.The input and output were separated by a resistor and a capacitor.
The hum balance resistors on the filament line are now larger, 2- or 3-watt resistors.
It improved the performance because the reverb changes proportionally with everything else when you change the master volume.
Reverb hum and noise get relegated to the noise floor–a big improvement.
The Swamp Thang is the speaker the Series III deserves: full, round bass and moderate highs.
For my part, I’m glad that all of my mods still work for the Series III.