Hello...new to this forum. I do have a question about adding an extra sub to supplement an existing 2 channel setup(preamp, amp, speakers). My preamp has a single output. I'm starting to call up modification services to add a sub-out. Is there an easy and safe alternative way on what I have right now? A friend of mine suggested to split the left channel output but I'm worried what it might do damage in the long run. I could sell the preamp and find a unit that will satisfy the purpose but I'm still going to buy the sub and cables. Can someone recommend a mod service if no way is possible? I live in SoCAL(WCovina area). Thanks.