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Bi-amping Denon 3805 in 5.1 to L/R(240watts@8ohms)
#87157 03/26/05 03:28 PM
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I was reading a review on the Denon 3805 in regards to purchasing M80 mains with the 4ohm power concerns at higher volumes. What I get out of the 7.1 Denon receiver is that when running on a 5.1 setup, you can
bi-amp the L/R front mains using the rear amps as the low biamp source and the L/R amps for the high biamp source. With the combined 120 watts into 8ohms it will provide 240 watts to each main @ 8ohms.
Is my thinking right here that you would guess to gain around 350 watts into M80's 4ohm speaker? Is that not a bad combination from a single receiver.

Your opinions would be great to hear.


M80 VP150 4-QS8 EP600 Monitor Audio S8 NAD T 773 Anthem MCA3 II Hitachi 57" projection
Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8ohms)
#87158 03/26/05 03:40 PM
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Yes you can do it but take it from one who has done it; the achieved actual output power has been greatly exaggerated. I noticed very little difference when I did it.

Some have reported a night and day difference. It wasn't there for me.


Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8ohms)
#87159 03/26/05 04:58 PM
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I imagine if you went the whole hog, picked up a good electronic crossover, and fed different signals into the two amps there would be more difference -- not saying that's worth DOING, just agreeing that "simple bi-amping" (both amplifiers get the same signal) probably isn't worth the effort.


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8o
#87160 03/26/05 08:04 PM
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No, it'll actually still only provide 120 watts to the speaker (I don't remember the math).


I am the Doctor, and THIS... is my SPOON!
Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8o
#87161 03/26/05 08:26 PM
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Maybe I read this wrong but, check the following review out;

http://www.audioholics.com/productreviews/avhardware/Denon-AVR3805_review04.php

Correct me if I didn't get the right info from this review, but if you are not using the 2 rear amps to run the rears and instead use them for half of the L/R fronts, at a minimum would you not reduce the heavy load draw on the amps normally regulating the main L/R speakers from the 4ohm, M80's. This in turn would allow you to provide cooler running on the original L/R amps, sharing the load.


M80 VP150 4-QS8 EP600 Monitor Audio S8 NAD T 773 Anthem MCA3 II Hitachi 57" projection
Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8o
#87162 03/26/05 09:54 PM
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Winterpeg,

Interesting question. Off the top of my head, I'd say there wouldn't be significant advantage, because the Denon's power supply still has to come up with the current into the low impedance that it "sees." But I'll ask my colleagues on Monday. And if you really want tons of current, get a big, fat separate stereo power amp for the M80s, or a couple of monoblocs.

I've never recommended bi-amping for typical home installations (there are applications for professional monitoring at extremely high playback levels where it can make a difference) because I've never heard significant audible differences in a normal-sized room (2,500 cu ft) with either bi-amping or bi-wiring.

Regards,


Alan Lofft,
Axiom Resident Expert (Retired)
Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8o
#87163 03/27/05 01:17 AM
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Peg, I believe that the consensus of the previous replies is correct. Although that site is generally a very reliable source of information, that particular point seems questionable at best. The outputs aren't "combined" and 240 watts don't result. Each half of the speaker is driven by a separate 120 watt amp section and can't "borrow" from the other amp in the unlikely situation that more was needed. As Alan points out, there's still just one power supply section in the 3805 to supply all of its amp channels. It would appear that at most there would be a reduction in the total load carried by the output transistors in two amp sections, but this wouldn't create any audible benefit and it would be uncertain if the service life of the sections involved would be significantly lengthened. In my view not worth the bother; in most setups the 3805 should be fine with the M80s as is.


-----------------------------------

Enjoy the music, not the equipment.


Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8o
#87164 03/27/05 03:42 AM
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It is looking pretty much like an absolute majority. It was probably an error in understanding. I guess it just looked a little to good to be true.

I'm sure the 3805 will do just fine as well. I have seen plenty of posts that say just that. I guess if it doesn't, then some future savings could be put aside for a couple of Outlaw mono's, which should cure any desire.


M80 VP150 4-QS8 EP600 Monitor Audio S8 NAD T 773 Anthem MCA3 II Hitachi 57" projection
Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8o
#87165 03/27/05 03:55 AM
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It's always good to explore these things, just remain suspicious about "too good to be true". Now if the extra amps in the Denon could be *bridged* to make one big amp that would probably be a different story


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8
Re: Bi-amping Denon 3805 in 5.1 to L/R(240watts@8o
#87166 03/27/05 03:59 AM
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In reply to:

Now if the extra amps in the Denon could be *bridged* to make one big amp that would probably be a different story




Even if the amps could be bridged you couldn't run a set of M80s with them.When you bridge an amp the amp will see the load as a 2 ohm load not 4.


Rick


"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud

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