Re: Separate amp for fronts
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Joined: Dec 2003
Posts: 10,420
shareholder in the making
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shareholder in the making
Joined: Dec 2003
Posts: 10,420 |
Can you guys explain why people add a separate amp for the fronts with say a 2809, 3808 or other similar quality of amps? Is it just for more power in the stereo music listening mode? When using in HT mode, it seem the fronts are not asked to do much, compared to the center, so would have much more headroom than would normally be needed in HT mode. What am I missing here? Because they want to, have spare money to burn and feel they are missing something with just their avr. Many actually need the amp because they have unusually large rooms or listen at insanely loud volumes in which case they can benefit from the extra power. There are those that say they can hear better dynamics when using seperate amps. I hope to find out for myself someday.
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Separate amp for fronts
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Joined: Aug 2004
Posts: 6,379 Likes: 7
axiomite
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axiomite
Joined: Aug 2004
Posts: 6,379 Likes: 7 |
Even in cases where the center channel carries as much or more signal than the mains, offloading the mains still frees up some power supply capacity for the center channel. It's like the difference between "one channel driven" and "all channels driven" power ratings. This won't help in cases where there isn't enough "one channel driven" power for the center channel to keep up, but in cases where there is lots of power going into both mains and center (ie when the power supply voltage in the receiver is likely to droop under load) offloading the mains can make a difference. The point about having bottomless power for music reproduction is also valid. Finally, stereo amps often have nice analog power meters, which IMO always improve the perceived sound quality
Last edited by bridgman; 03/16/09 08:00 PM.
M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39 M5HP, M40ti, Sierra-1 LFR1100 active, ADA1500-4 and -8
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Re: Separate amp for fronts
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Joined: Feb 2009
Posts: 562
aficionado
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aficionado
Joined: Feb 2009
Posts: 562 |
Even in cases where the center channel carries as much or more signal than the mains, offloading the mains still frees up some power supply capacity for the center channel. It's like the difference between "one channel driven" and "all channels driven" power ratings. This won't help in cases where there isn't enough "one channel driven" power for the center channel to keep up, but in cases where there is lots of power going into both mains and center (ie when the power supply voltage in the receiver is likely to droop under load) off loading the mains can make a difference. The point about having bottomless power for music reproduction is also valid. Finally, stereo amps often have nice analog power meters, which IMO always improve the perceived sound quality I was just going to ask about the lighter load on the PS. Glad you confirmed that thought. All the above makes sense now. Makes me lean harder towards the 3808 with a slight edge over the 2809 in power and with a larger power supply I am sure, as it weighs 11 lbs (39%) more. Then I f I feel the need to unweight the fronts from the 3808, I'll feel the surrounds will have plenty of power (maybe I am not as power hungry as some). I have read it here (JD? JohnK?) that if you bother to add an amp, it should be double the AVR's rated power. Is this just a common sense thought of not to bother with the expense for just an incremental increase, or is there more to it? This is just to edumacate myself. I don't see the need for my situation. But hey, when the term discretionary income comes back into my vocabulary, nice to have options. I am trusting we are under 'forum/ client privilege'. None of this gets back to the wife!
Last edited by davekro; 03/16/09 08:50 PM. Reason: spellin'
Dave
"In theory, practice and theory are the same. In practice they're not."
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Re: Separate amp for fronts
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Joined: Dec 2003
Posts: 10,420
shareholder in the making
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shareholder in the making
Joined: Dec 2003
Posts: 10,420 |
To audibly hear a difference the power needs to double, so if you get the 3808, you will need an amp that is capable of 260W/ch to get a noticably louder system, not that you might not hear it cleaner at high SPL for the same amount of power, say an amp with 150W, since it appears outboard amps tend to have a little more headroom built in(lower specs than actual output).
Jason M80 v2 VP160 v3 QS8 v2 PB13 Ultra Denon 3808 Samsung 85" Q70
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Re: Separate amp for fronts
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Joined: Feb 2009
Posts: 562
aficionado
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aficionado
Joined: Feb 2009
Posts: 562 |
To audibly hear a difference the power needs to double, so if you get the 3808, you will need an amp that is capable of 260W/ch to get a noticably louder system, not that you might not hear it cleaner at high SPL for the same amount of power, say an amp with 150W, since it appears outboard amps tend to have a little more headroom built in(lower specs than actual output). Oh, that makes sense. I recall now the rule of thumb that you need to double the power to get a 3dB SPL increase. 3dB being what it takes for the average listener to notice the difference. (Hey, JD over on the AVS thread, your repetition of this concept to me is FINALLY sinking in.)
Dave
"In theory, practice and theory are the same. In practice they're not."
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Re: Separate amp for fronts
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Joined: Jun 2003
Posts: 6,833
axiomite
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axiomite
Joined: Jun 2003
Posts: 6,833 |
The 260 is assuming the speaker is an 8ohm speaker. Even more if your talking 4 ohm seeing the 3803 should put out around 200 watts into 4 ohm.
Rick
"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud
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Re: Separate amp for fronts
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Joined: Feb 2009
Posts: 562
aficionado
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aficionado
Joined: Feb 2009
Posts: 562 |
Rick, Well now you are compicatin' stuff. If I ever do think to add an amp, I CAN remember to come back here and ask for a rec.
Dave
"In theory, practice and theory are the same. In practice they're not."
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Re: Separate amp for fronts
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Joined: Feb 2009
Posts: 3,466
connoisseur
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connoisseur
Joined: Feb 2009
Posts: 3,466 |
But a separate rated at 260 into 8 Ohms is also more than likely to gain around 50% more power into 4.
Pioneer PDP-5020FD, Marantz SR6011 Axiom M5HP, VP160HP, QS8 Sony PS4, surround backs -Chris
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Re: Separate amp for fronts
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Joined: Jun 2003
Posts: 6,833
axiomite
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axiomite
Joined: Jun 2003
Posts: 6,833 |
The point being with a 4 ohm load you would need at least a 400 watt into 4 ohm amp for any real gain. A 260 watt amp is not quite going to get ya there even if you get the 50% increase....... real close though .
Rick
"A fear of weapons is a sign of retarded sexual and emotional maturity." Sigmund Freud
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Re: Separate amp for fronts
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Joined: Feb 2009
Posts: 562
aficionado
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aficionado
Joined: Feb 2009
Posts: 562 |
Boy are you splitting watts there Rick, or watt. Can't ya give a guy a dime's worth of watts?
Dave
"In theory, practice and theory are the same. In practice they're not."
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