The glock preamp I recently put in my 5594 has decided to buzz with the bridge pickup. It didn't buzz initially so I'm at a bit of a loss to know what's changed. I tried shielding the bridge pickup cavity and running an earth wire though to the preamp cavity. It's quiet in passive mode, no matter how the pickup is set, so I'm thinking the shielding is ok. In active, it's quiet when the bridge pickup is in parallel, buzzes a bit in single coil and buzzes a lot in series mode. I'm stuck, any hints?