I have always been confused by the term "D.I. out". If I'm not wrong, D.I. is an abbreviation for "direct input", and it seems like an oxymoron - direct input...out. I think I understand the XLR out, which is, I believe, the output signal taken after the preamp, with the option (sometimes) of having pre or post EQ. This is, I think, a 600 ohm (whatever that means) balanced output. I think "balanced" means there is some kind of noise cancelling signal, and if both ends are balanced, the noise gets cancelled by this signal that both ends understand. When an amp has both a D.I. out, and an XLR out, is the difference that one is balanced and the other is not, or is it simply the type of connector, as it seems a D.I. out is always a quarter inch connection and XLR is XLR. And why not call a D.I. out, just a D.O., or direct out? Would you use this connection to have something come "in" to the amplifier? Last, I am never sure when I use an XLR out, whether to use the pad or not - it seems like it doesn't matter. I am primarily interested only in running direct to a live mixing desk situation, but I'd like to understand all this stuff for live and/or recording. Sorry if my questions are confusing. I hope they are understood.