QSC Series Three 3500 as guitar/wedge amp?

[Mberg9000]

A couple of years ago I picked up a custom built speaker cabinet for $40. On top is a QSC Series Three 3500, which is connected to two subs (I have no idea what they are). I normally hooked it up to a small soundboard I have, and it worked well enough as a sort of "ghetto" PA system for band practice and jamming. The only bad part was that the whole thing weighed a ton, and one of the subs recently took some damage.

I'm thinking of cutting the whole cabinet down and just using one speaker with the QSC amp as "ghetto" guitar/vocal amp. However, I'd like to eliminate the need of having to use a soundboard with it as well. Is it evne possible for me to do this? I tried plugging a 1/4 inch cable from my guitar into the channel 1 1/4 input on the back, but I got hardly any sound regardless of where the volume control was.

If anybody could give me any advice, it would be really appreciated. I'll admit that I'm a noob when it comes to pro audio, and many of the terms and concepts can be a little bit intimidating. However, the topic interests me and I am willing to learn and try my hand at it.

(The manual for the amp: HTGuide Forum - QSC Series Three 3500 pro amp)

Thanks a lot!

 

[cloudhopper]

The power amp is expecting a line level input. Your guitar is only supplying instrument level signal. To get full power from your power amp, you need to boost the guitar signal to line level but that's not the only problem. A guitar preamp does significant shaping and processing to the signal. The mids are most generally scooped around 700 Hz to 1 KHz and most guitar preamps also provide distortion and compression thru a variety of means. Strictly boosting the signal to line level usually results in a very bad sounding guitar tone. Guitar amps are quite different from PA or HiFi in the sense that you want transparency in PA and HiFi but the guitar amp becomes part of the instrument and you want it to add color, tone shaping, compression, distortion ect. One way to do this with your setup is to add a preamp pedal between your guitar and power amp. Just a simple distortion/boost pedal will get your signal level up a bit too. Something else to watch out for, guitar speakers are designed to be abused, some guitar distortion can easily go square wave or very near to square wave and normal PA speakers can't take this. Guitar speakers also are very far from uniform frequency response and they too become part of the total instrument.