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Re: Anyone using the Denon 3808CI and M80’s
Wid #182857 11/10/07 07:39 PM
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If the design is indeed different than past designs, then I guess I need to know WHAT that difference means.

Re: Anyone using the Denon 3808CI and M80’s
CV #182858 11/10/07 07:41 PM
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Thing is, it's not. It's the same feature that Yamaha, Denon, whoever's been offering for the last few years or so. You just redesignate those back amps to the front speakers.


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Re: Anyone using the Denon 3808CI and M80’s
Ken.C #182861 11/10/07 07:52 PM
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Mo ... if I went out and installed a second drive shaft from the transmission to the rear end of my Ford truck I would then be doubling the HP and torque value rating of my truck, right? 1,100 ft pounds of torque in a stock 3/4 ton pickup truck, wow.

Isn't this basically what you are saying?


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Re: Anyone using the Denon 3808CI and M80’s
RickF #182884 11/10/07 09:21 PM
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You know what the caveat to this whole thing is? You can't exceed the maximum voltage of each amplifier. Since they're all connected in parallel, you can source three times the current but the rail voltage doesn't change. You'd have to find a very low impedance speaker to take advantage of the extra current. Having the current doesn't do any good if you experience voltage collapse.

The rail voltage of my Denon is about 35 volts. The A1400 on the other hand has a rail voltage of around 90V.

So why do they offer this then? Is it for low impedance speakers (like 2 Ohm) or is it so that you can double up on fronts?


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Re: Anyone using the Denon 3808CI and M80’s
Mojo #182886 11/10/07 10:02 PM
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Nope, it's marketing. Plain and simple.

From what I've read, the only real benefit to biamping comes with a) extremely high volumes and b) external, active crossovers, neither of which you will achieve with a receiver.

Last edited by kcarlile; 11/10/07 10:03 PM.

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Re: Anyone using the Denon 3808CI and M80’s
Ken.C #182887 11/10/07 10:11 PM
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I think there is some confusion between bi-amping and bridging. Bridging does mean combining two channels on the receiver into one. Bridging is much rarer as a feature.


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Re: Anyone using the Denon 3808CI and M80’s
EFalardeau #182889 11/10/07 10:22 PM
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I don't think I've ever seen bridging on a receiver, but that would certainly double the power.

I think someone told me awhile back that there are very few amps that can bridge into 4 ohms.


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Re: Anyone using the Denon 3808CI and M80’s
EFalardeau #182890 11/10/07 10:33 PM
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Actually I had two lapses in thinking:

1. In the case of disconnecting the strap and using the rear channels for bi-amping, I neglected the fact that the two speaker halves each have a larger impedance while the available rail voltage has not increased. There may still be a marginal benefit but I doubt it's of any practical significance.

2. In the case of multi-channel connected to the fronts, the speaker impedance doesn't change but the rail voltage remains the same. More current is available but without voltage there is no "pressure" to push the current out.

However, if anyone has low impedance speakers (say a couple of Ohms), both of these ways would power them very well.

So I'm glad I drew that block diagram for myself \:\) .


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Re: Anyone using the Denon 3808CI and M80’s
Ken.C #182891 11/10/07 10:41 PM
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Onkyo-875 has that (not the 805), but they don't support 4Ohm bridged.


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Re: Anyone using the Denon 3808CI and M80’s
EFalardeau #182897 11/10/07 11:55 PM
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All the home amps I have seen that can be bridged recommend a minimum of 8 ohms in bridged mode.


Rick


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