Mission 5E3 completed

[Bruce / Mission Amps]

What do the Humbucker 1 & 2 mods do exactly?

There are actually three mods in the HB kits.
One is a fixed bias phase inverter mod and two mods are RC circuits to cut the low woofy bass down.
One of the two has all the parts to split the two cathodes from the 12AY7 socket and extra parts for fine tuning.
The three part HB mod kits also come with a pair of switches so you can bypass the HB I and II mod(s) and get the stock tone back.
The fixed bias phase inverter mod is just parts and there is no easy way to make it switchable so once it is installed you are stuck with it until you remove it.
I like all three!!
To make the mods easier for my customer, the Mission Amps eyelet board has an extra eyelet on it used to split the cathodes of the 12AY7 socket for better "tuning" and the MA 5E3 chassis comes with two holes already punched in the chassis, by the preamp tube's sockets, so the two switches can be added later if the builder wants to install the HB I and HB II mods, but still hear what it sounded like stock.
Works really well for different guitars and their different pickups.