"Dave xxxx" wrote in message
k
On another forum a chap says, he has been told, its ok to
use a Quad power amp (140 watts) with a Quad 405 (100
watts) with the same pre amplifier.

The idea being the 606 powers the bass and the 405 the
tweeters.

This story comes around every once in a while - different details, same
basic old wife's tale.

Speakers being used Spendor s5e

Will this work ?

Yes, but without some engineering, it is pretty pointless.

Said Quad told him they have the same "gain"

Not true.

http://www.hifiengine.com/download_c...p?quad_606.pdf says the
606 puts out 140 watts with 0.5 volt input.

http://www.hifiengine.com/download_c...5_brochure.pdf
says the 405 puts out 100 watts with 0.5 volt input.

http://stereophile.com/floorloudspea...or/index4.html

Shows a fairly typical impedance curve. Note that the impedance of this
speaker in the tweeter's range is 10 ohms, which means that it is
providing only a small fraction of the total load on the power amp that is
driving it.