If your rig has more than one amp in it and you are experiencing excessive hum or buzzing then you may have a ground loop. A ground loop is an unwanted current in a conductor connecting two points that are supposed to be at the same potential, often ground, but are actually at different potentials. Ground loops can be detrimental to the intended operation of the electrical system. Translated into guitar amp terms means that if each one of your amps in your rig has its own ground then you will have a ground loop and will get all that nasty hum. In a multi-amp set-up you only want to have one of your amps grounded. How do you only ground one of them? Simple, by using ground lift adaptors on all but one of them. This also applies to any external reverb unit like the vintage Fender units. Doing this will eliminate the hum and keep you safe from any chance of electrical shock. Ground lift adaptors are available at harware stores and even at supermarkets. 300Guitars Shop My shop is located at 1 Executive Dr Unit L Toms River, NJ 08755 Please feel free to email me if you have any questions or are in need of some tech work. Monday: 10am - 5pm Tuesday: 10am - 5pm Wednesday: Closed Thursday: 10am - 5pm Friday: 10am - 5pm Saturday 10am - 2pm. (I am in every other Saturday). I am also an Eminence, Mercury Magnetics, Mojo Musical Supply dealer. I do all the tech work myself so you deal directly with me. I am a one man shop and my hours can vary so please contact me to confirm that I will be open. Email me: firstname.lastname@example.org Call or text me: 848-218-0362 Shipping Info for all repair work: Please ship all repairs to: 1 Executive Dr Unit L Toms River, NJ 08755 I am currently offering all phases of guitar work which includes: Set-ups Fret dressing Re-fretting New hand cut custom bone nuts & saddles Electronics work And amplifier work which includes: Basic maintenance Bias adjustment Repairs and restorations Modifications And more.... Testimonials: David Nicholas - The 20watt amp is sounding fantastic! Delivered the goods at the gig and I'm finding cool tones all over the place with it. Love the cab w Emenince Tonkerlites too- perfect for my sounds! Makes the 12 string sound like a grand piano! Peter Lacis - I had an audition for something recently that was all about Led Zeppelin I -- my custom Pennalizer BLEW THE MINDS of the guys I was playing with. They couldn't believe the sounds coming out of that amp. That album was never in my mind when I came up with the idea....so that's yet another testament to the amazing work that you do. Scott Goldberg - I am very satisfied with the set-up, and the fast turn around. With the "lower" action it feels easier to play. I will definitely spread the word.