Active 3 way system

[Bernards Radio]

My system is Linn Kaber speakers currently fitted with 3 way passive crossover and driven by two LINN LK100 amplifiers one amp wired to bass/mid (linked) and the second to the tweeter terminals . Prior to buying the second LK100 I had just one unit driving the Kabers and I found it very much underpowered the amp getting hot and shutting down frequently , the Kabers are known to be difficult to drive in passive mode and lacking in low frequency performance unless driven by a 200 watt amp . The pre amp is a Linn Kolektor , I have the volume control at 90 to 95 most of the time which gives me about 20 minutes before automatic shutdown . I realise that repeating this behaviour would probably eventually fry the output transistors . Adding the second LK100 and 'bi amping' as per the Linn instructions does not help , I cannot discern any difference in output or quality of the sound which I suspect is possibly because bi amping into a passive crossover wastes most of the power in the crossover ? I have now bought a Kaber active three way crossover and have no money to buy a third amp just yet . I am planning to use an old Sony STR-D515 which I bought for £5 temporarily to drive the tweeters , I realise its an unsuitable amplifier and will eventually either buy a third LK100 or assemble a gainclone . Linn reccomends using the best possible amp on the tweeters and if necessary lower power amps on bass and mid range but I dont understand the logic behind this , the tweeters surely only need a few watts whereas the woofer needs all the real power , there seems to be a lot of conflicting advice on this subject ?

[AndrewT]

I contend that the peak SPL from any of the drivers can be around the same volume.

This requires that the peak voltage fed to the driver combined with the driver sensitivity should aim for the same target SPL.

The average power fed to the three drivers will be very different, even if their sensitivities were identical. This average driver power can be used to determine PSU and heatsink design.

[Bernards Radio]

Andrew , thanks for the advice , I have in the meantime tried the Sony STR-D515 on a pair of vintage Dynastat hybrid electrostatic speakers and seem to have fried it as its now immediately going into 'protect' mode even with no inputs or output connected , have downloaded the service manual from hifiengine to see if I can fix it , if not then it will serve as a suitable box to house a gainclone as that seems to be the only positive benefit of this particular Sony amplifier .