Pre-amp?

I,ve recently bought a new amp and was gonna get rid of my old one (crappy 10w toneless piece of sh**e) then i thought what would happen if i run my guitar thru the old amp into the new one? would this effectively give me a 10w pre-amp? will it give me more output overall?? (new amp is 15w) will it blow the pre-amp and/or output circuit (solid state) in the new amp? or will it just do nothin? any info on this grately appreciated guys, cheers.

im assuming that u meen to use the line out or headphone out or somthin from your 10 watt amp which probably wont boost your signal much if at all, but it will add any effects from your 10w amp. it shouldnt damage your 15w amp unless you are planning to plug the speaker cables into your 15w amp guitar input.

It won't make it any louder. The pre-amp section shapes the tone, while the power amp section boost the signal so you can hear it. The Power amp section is where the volume comes from.

Since you said your first amp is toneless, it would be pointless to use it as a pre amp.

Cheers guys, appreciate your help.