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CLASS A
11-08-2004, 02:28 PM
Dear all,

I m using the Plinius SA250 IV ( 250WPC class A) per channel to drive the JBL 250Ti jubilees. My question is, what sort of improvements if any if I buy another SA250 and go mono. The SA250 will produce 1KW per channel in banlance mono mode and the Jubilees can handle 400W. Is this over kill or am I wasting money?, I m sure you guys out there must have tried the mono configuration with the JBL 250ti.
Thanks in advance. :)

Robh3606
11-08-2004, 02:35 PM
Hello Class A

Do they sound like they are compressing on peaks at a bit above your average volume setting??? Only you can tell that depending on SPL, room size, and of course what you listen too. Try an evaluation with a demanding passage in mono one channel only in stereo mode, then strap the amp and replay.

Rob:)

CLASS A
11-08-2004, 02:44 PM
Rob
Thanks for that, they don't sound at all over strained even at high levels. At mo, the volume switch starts at 7 o'clock and the loudest I ever used is at 12 o'clock and that is killing my ears ( complaints from next door ) :) .
I suppose I m not looking for more volume but more dynamics, drive and sheer kicks from the JBLs. Would image and soundstage improve upon more disposable power on tap?.
Cheers

Mr. Widget
11-08-2004, 09:46 PM
I would spend the money elsewhere...anyone biamp a pair of JBL 250Ti Jubilees?

Widget

Ian Mackenzie
11-09-2004, 02:50 AM
In my own experience with Class A the only further improvement may be bi amping if you can.

Its unlikely a the class A amp of that size would ever sound compressed as its a hi current amp by design.

Ian

CLASS A
11-09-2004, 03:35 AM
Thanks mate....what are the pros and cons between mono config and bi amping?, and with bi-amping, would I need to have both amplifier the same output or can I use a smaller amp for the mids and highs?.
Cheers. :)


In my own experience with Class A the only further improvement may be bi amping if you can.

Its unlikely a the class A amp of that size would ever sound compressed as its a hi current amp by design.

Ian

Ian Mackenzie
11-09-2004, 04:52 AM
With mono mode you are applying more voltage across the full bandwith but still through the passive crossover and all 4 drivers. I am not sure the amps would be as clean ad this may stress the crossover.

In bi amp, you will still apply the same net crest voltage (1000 watts dynamic range) but the signal is divided b/n low and high pass by an active filter so one amp sees highs and the other lows.

Less distortion from the amps most likely and less distortion products from the passive crossover and much less lost power by elminating the woofer passive filter and midrange pssive filter, also better cone damping.

I would tend to use identifical amps in this situation.

But do you really need to do this?:hmm:

Ian

CLASS A
11-09-2004, 05:07 AM
Thanks Ian

I would have to find out if my amp allows me to bi amp. Not sure how to wire the bi amp mode. would I need a external active cross over to do the job?.
Cheers

scott fitlin
11-09-2004, 08:51 AM
Thanks Ian

I would have to find out if my amp allows me to bi amp. Not sure how to wire the bi amp mode. would I need a external active cross over to do the job?.
CheersYou will need two amplifiers to bi amp, one for the highs, and another for the lows! You will need an active crossover, and as Ian and others said, this will probably yield you better results than strapping two amps in bridge mono. You will find that a properly setup bi amped system does improve the dynamics, and just about everything else, too!

As for two of your amps bridge to make 1KW each, I dont think you really need that kind of power! And one could get in trouble with 1000w a speaker thats rated for 400w!