Bi Amp 4343's

[Triumph Don]

Well I'm close to replacing the L 300's with 4343's. I have a McIntosh 2255, and 2 Crown DC 300 A's. What do you think about the Crown's bridged to mono and the 2255 for the top?

[Robh3606]

Sounds like a plan to me I have used DC 150 Serries 2 and PS-200 straped and they were both real solid on the low end.

Rob:)

[Tom Loizeaux]

I bi-amp my 4343s and drive the lows (below 250Hz) with a Crown PS-400, and the highs (250Hz and up) with a Crown PS-200. This setup sounds great, but I feel I could use a little more power to keep the signals clean when I really crank these. I think your amp combinations sound fine.
I like matching amp types when working bi-amp, and I really like Crowns, so if I were to go bigger, I might have to go to a Studio Reference One and Studio Reference Two... a heavy investment!

Tom

[ngccglp]

Hi Tom,

Do I need to get an external crossover for my 4333A to bi-amp. I noticed a switch behind that says internal or external crossovers. Can I just hook up two amps with the switch at the external crossover position?

Thanks.

David

[Tom Loizeaux]

Those 4333s are set up to take a full rage signal and use the internal crossover to divide the signal in to 3 bands...or switch the selector on the back to EXTERNAL and send Lows to the lower input connectors and Highs to the upper input connectors. When running in this bi-amp mode, you must use a stereo active crossover, set to divide around 800 Hz, and then send the Low output to a stereo amp and the High output to a different stereo amp. Then the Lows go to the lower inputs and the Highs go to the upper inputs. The Lows go directly to the woofer, while the Highs go through the upper section of the passive crossover and divide the signals to feed the compression driver and tweeter. The LEVEL controls on the front still affect the output levels of the mids and highs. If you need more output from your Highs amp, you can always turn these LEVEL knobs all the way up, adjusting the balance if needed, as you don't need to balance these with the woofer when running in the bi-amp mode.

Tom

[ngccglp]

Hi Tom,

I've been thinking about your post. For the 4333A, if a passive circuit exists for both the low and the mid/high, then logically, I do not need an external crossover. What I need is just two stereo amps, one to drive the mid/high and the other to drive the low.

Pls advise. Thanks.

David

[Tom Loizeaux]

Originally posted by ngccglp
Hi Tom,

I've been thinking about your post. For the 4333A, if a passive circuit exists for both the low and the mid/high, then logically, I do not need an external crossover. What I need is just two stereo amps, one to drive the mid/high and the other to drive the low.

Pls advise. Thanks.

David

David,
No, if you use the full internal passive crossover (INTERNAL position), you can only drive it with one amp's output delivering a full frequency signal. If you switch to EXTERNAL on the back of the speaker cabinet, you seperate the woofer from the HF and UHF drivers, and then would need an active crossover to seperate the signals and send them to two different stereo amps, one for the Lows and one for the Highs.

Tom

[subwoof]

To "ngccglp"

STOP STOP STOP

the passive circuit on the highs is between the HORN and the TWEETER.

IT WILL NOT keep damaging lows out of the horn and if you wire it that way it will cost you over 500 in parts.

Biamp is NOT the same as biwire.

[ngccglp]

Thanks guys. I will not attempt any 'unauthorised' connection without the endorsement of this forum. ;)

Still learning.

[Rolf]

Why say so much about so little?The switch in external will send all frq to the woofer, and frq from 800Hz and up to the mid/hi. That is why you need a external crossover, to avoid frq above 800Hz to enter the woofer.

Regards

Rolf

[Tom Loizeaux]

[QUOTE]Originally posted by Rolf
[B]Why say so much about so little?The switch in external will send all frq to the woofer, and frq from 800Hz and up to the mid/hi. That is why you need a external crossover, to avoid frq above 800Hz to enter the woofer.

Regards

Rolf

Rolf,
What you're saying is almost correct. The active crossover also needs to send only signals above 250Hz to the upper input terminals in the EXTERNAL mode, as the 2121 10" driver will not get the bass filtered out of it's input path, and damage might occur, let alone a very unbalanced sound.

Tom

[Robh3606]

Hello Rolf

Why say so much about so little?The switch in external will send all frq to the woofer, and frq from 800Hz and up to the mid/hi. That is why you need a external crossover, to avoid frq above 800Hz to enter the woofer.


No to keep 60hz out of the compression driver. Look at the schematic. The biamp switch drops out both the high and lowpass sections of the 800hz crossover. That leaves the compression driver vulnernable. There is a series protection cap in the "B" but you don't have a high pass network.

http://www.jblproservice.com/pdf/Studio%20Monitor%20Series/4333B.pdf

Rob:)