Bridging amplifiers
 

I have two quad 303 amps, both upgraded with new caps, and I was wondering: is it possible to bridge the outputs to double the output; thereby using one amp per speaker? Is bridging simply done by putting a jumper between the negative of the right output and the positive of the left output and then feeding the speaker from the positive of the right output and the negative of the left output; and doing the same to the inputs? I am a rookie at both hi-fi and diy audio so any help would be appreciated.

danbmellow,
try these two linkes thay are both from rod elliott's site:
http://sound.westhost.com/project20.htm
http://sound.westhost.com/project14.htm
In your case you should go with the second link.

Kinser

If you have a look here

http://home.jps.net/~graceaudio/405mono.pdf

This is what Quad did with the 405s. The first of the circuit is probably more usfull unless you want to drive high impedance loads. I have copied this circuit and used it with 306s and it works very well though I would suggest you use a multiturn pot for the input ballance as it makes setting up easier. If you use the true bridged version diagram 5 the speaker will have a capacitor at each end and the capacitor bias will be indeterminate which is not a good thing with electrolytics.

Stuart