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View Full Version : Stereo Amp Question



KrisH
March 9th, 2008, 06:23 PM
Maybe someone can offer me insight or opinion on my situation.

A few months ago I got a Behringer Ultratone K3000FX, which is a 300 watt, 4-channel PA/keyboard combo amp, with stereo inputs on each channel (two 1/4" inputs for each channel). The left input is also labeled for mono input. I got this as a general purpose amp because it seemed best for both bass and guitar, when running them through my pedal board/amp emulator (Digitech GNX3000).

When I first got it, I plugged my bass directly into the amp, and noticed that it isn't really as loud as I'd expect a 300 watt amp to be -- doesn't matter whether I plug into the "mono" jack or the other one. But when I use my pedal board, which has stereo output through two mono jacks, the amp roars! In other words, something is plugged into both the right and left jacks of the amp channel. I get some volume drop when I unplug one cable from the pedal board -- doesn't matter which one.

Obviously, part of the difference is because the power is being split between left/right, and both sides must be used to get the full benefit of the wattage. But it's also pretty obvious that overall, I'm feeding a hotter signal from my pedal board than from my guitars.

My question (finally!) is this: will feeding a hotter signal into the input damage the amp? I set the line-out output signal from my pedal board at about 1/2. The Behringer is a keyboard amp, so I presume it is designed to handle inputs from powered equipment better than from passive pickups. So how hot is too hot? The amp sounds really nice with this setup (I especially like emulating an Ampeg SVT for my basses and a Fender Twin Reverb for my guitars), and it has held up well so far, but I don't want to burn it up!

wingsdad
March 9th, 2008, 09:51 PM
You're fine. The GNX3000's output is a line-level pre-amp signal, at either -4 Db or -10 Db, akin to that of bass or guitar with active electronics (powered usually by a 9V battery), while you're bass or guitars are passive signals (I assume). It's hotter, but not abnormal.

KrisH
March 10th, 2008, 02:15 PM
Kinda what I was hoping. Although I was surprised that the peizo pickup and pre-amp combination in my Ashbory didn't put out much more of a signal than my passive pickups. But that's not really an active pickup, is it?

I never learned this stuff way back when. I dunno if they even had active pickups back then. :confused:

wingsdad
March 10th, 2008, 10:53 PM
Well, yeah, 'active' electronics with electric guitar pickups means there's a preamp onboard. So that is surprising about your Ashbory. This may sound dumb, but was the battery fresh?