Quote:I do not understand what "Balanced" is. How is it that the amp with the XLR connection - the UFO2, is not balanced, but the standard amp with this new wiring is balanced?
A lot of people misunderstand what balanced (I prefer to call it differential, but I'll stick with common usage) means. It is the electronics that are balanced, not the connectors or the interconnects.
Lets start with a "normal" single ended signal. It is the Left and Right channel relative to ground. And it comes out of the amp on the L+ and R+ speaker terminals, with the - terminals at ground. So to voltage difference that drives the speaker is just the voltage of the signal.
In a balanced signal L and R are relative to their inverted signal instead of ground. So a balanced amp (or other component) actually needs 4 separate channels for L+, L-, R+ and R-. And what comes out at the speaker terminals is (more or less) twice the voltage difference. For example the left channel is L - (-L) = L + L = 2L and you get the bonus of canceling any common noise in the two phases when you do the difference.
A balanced signal is traditionally carried on a cable with a 3 pin XLR connection for the + and - phases and ground, but there is nothing magic about the connector or the cable. It is what the component does with the signals that determines whether it is actually balanced or not when it comes out the other side.
What a UFO with an XLR connection does is use a transformer to turn the + and - phases of a balanced signal into a single ended signal (same thing a ZBIT does), which is what gets amplified. What the standard amp with the special cable does is use the L and R channel of a stereo amp to amplify the + and - phase of a true balanced signal. In theory you could replace the L and R RCAs with a XLR to make it look like a "regular" balanced mono block, but that is only a cosmetic change, the internal wiring in the amp would stay the same.
That may very well leave you more confused then when you started, but that's what I've got.