I recently got an Engelhardt ES-1 upright and had a Barcus Berry insider pickup installed. I am using a Tech 21 Sansamp bass driver as a preamp into either my SVT classic head or my Peavey TKO115. My problem is I just get a hum on both amps, I dont really think im getting a good signal from the pickup. I tried messing with settings, more volume on the DI, more volume on the amp, more EQ on the DI, several different combinations. Nothing works. I just get a hum and I dont really hear any amplification happening. Is it because of a grounding issue? Is the Sansamp not good for vibrational pickups? All help is appreciated.