Hi, I was wondering if it would be a good idea to use the head from my marshall guitar amp with a bass cab, just untill i have enough money to get a bass head. My marshall mini stack is 15 watts but on the back of the head it says it is 40 watts. I know it wouldnt sounds great but i dont want to damage the speakers on my guitar amp. Also it says Output: 15 watts RMS. I would also like to know if this head would work on a peavey mark IV bass cab which has 2x8" speakers. 4 ohms. 300Watts RMS, 600W peak. Thanks.