Expert: Cleggsan - 9/6/2008

Question
Need to replace part of my music system, (the old powr amp died).  On a tight budget and may be able to get a Sony DG520 5.1 rcvr at a bargain price.  to be used for music in stereo only. What might happen electronically if the front and rear outputs are connected to the same speaker?  I realize this lowers impedance but the speakers are about 50 ft from the stereo. I intend to use the old pre-amp for my phono into one of the standard line level inputs (this rcvr has no phono input)  Any suggestions/warnings etc...

Answer
You should never connect one speaker to two amplifier outputs or you will have a kaput amplifier on your hands!  (UNLESS: The amplifier outputs are bridgeable - but most receivers do not have this functionality.  Bridging is mostly done in car amps and high end audio stuff).

The problem is that the output impedance of an amplifier is very low; less than one ohm.  Maybe less than .1 ohm.  So, if the two outputs are tied together it is like placing a short across the output of the amp.  It will go up in smoke shortly thereafter!

Better to leave one amp with no load until you can get another speaker to put on it.

Does this help? Let me know if there is more.

C