Amp/connection hiss/buzz

TheGreatSealof · #1 12-01-2010, 06:06 AM

I have an Ibanez SG300 active bass and a Fender Rumble 75 amp. When connected at home, there is a constant hiss emanating from the amp. Especially bad when adjusting highs on pre-amp guitar. I visited the store where puchased and plugged in bass/amp. Perfect! Quiet. They suggested that maybe I have a grounding loop issue at home that produces the problem. I purchased a Hum X hum exterminator from EBTech per the store suggestion. I plugged in at home, same issue. Hiss and buzz. Is there a problem with my house wiring? There are no flourescent lighting and the grounded plug is on an outside wall. Do I need to call in an electrician? Any suggestions will be greatly appreciated.

Bob Lee (QSC) · #2 12-01-2010, 01:05 PM

No ground loop. No house wiring problem. Get your money back on the hum exterminator.

Is it buzz or is it hiss, or a combination?

Does it change when you turn the bass volume up and down? How about when you turn the amp up and down? Is it present when nothing is plugged into the amp?

TheGreatSealof · #3 12-01-2010, 07:49 PM

It is a hiss.

It is louder when I turn up the bass volume. I have to mute the active high controls on the amp and bass to reduce the hiss but the sound is muddy and terrible.

When turn on the amp, there is a low hiss but is much higher when the volume is maxed. I think this would be normal.

I have plugged the amp into several plug outlets throughout the house, but the results are the same. Hiss is definately louder with the bass plugged in.

The issue, I believe is my house power may not be grounded properly. At the shop where I bought the gear, there is no hiss, nothing. very quiet and great sound.

Thanks for your support. I really believe I will need an electrician to check the house for proper electrical grounding.

Bob Lee (QSC) · #4 12-02-2010, 10:27 AM

You don't need an electrician and don't need to check the electrical grounding.

If the hiss is louder with the bass plugged in, and it changes volume when you turn the controls on the bass, then the dominant source of the hiss is in your bass. There might be an issue in the active electronics that needs to be repaired.

At the shop, were you trying it with your bass? If so, is the background ambient noise at your house quieter than at the shop? If it is, then the amp might seem quieter at the shop because the ambient noise masks it.

TheGreatSealof · #5 12-02-2010, 11:13 AM

Yes, this hiss is louder with the bass plugged in. The shop was quiet. The gear is completely silent at the shop but noisy at home.