[GT40FIED]

Basses with guitar amps don't mix well at all. A bass emits a much lower sound frequency than the general guitar amp can handle. Look up the frequency response for a guitar vs. bass amp and you'll see what I mean. I built, sold, and fixed amps for a few years during high school at a local shop and their parts are usually VERY different. The speaker selection in the amps might be the same, but the solid state circuitry inside the amp won't let it hold a bass frequency through a guitar amp. I've even tested them. I own an old 2x12" Ampeg guitar amp that I've played through for years and my brother plays bass, usually through an 8x10" bass cabinet but through a Fender bass amp for practice. When I plugged the bass into the Ampeg even at relatively low volume it almost blew out the speaker voice coils. The whole time it sounded distorted due to the enourmous harmonic resonance. If I were you I'd splurge and buy a used practice amp for around $150 or so. But then again, if you've got a few guitar amps that you don't really care about, then you can play through them until they give out.