Quote:
Originally Posted by mjpearce023 /forum/post/20871037
The cheapest receiver I see that you can buy new right now is the Yamaha 667. The 867 is also pretty cheap right now and has preamp outputs and adds networking. I think it’s good to have preouts just in case you want to try out an amp in the future. I found a 2 channel amp on craigslist and bought but it didn't make any difference with my Denon 3310 so I sold it on craigslist. Some systems have plenty of power without needing an amp. Like it was mentioned, it depends on the speakers and it also has a lot to do with the room size as well.
The RX-A700 is another good choice.
Regarding whether or not you "need" an external amplifier depends on a few factors, some of them have been mentioned here (room size being a big one), some of them haven't (like speaker efficiency, target SPLs, and perception of loudness).
Some receivers, but not all, will deliver on their claimed output (or close enough that we don't care; I'll come back to this in a minute) - price usually doesn't dictate this, and there are some (ungodly) expensive receivers out there that absolutely do not approach their claimed outputs.
Regarding "close enough that we don't care"...
- In order to perceive a doubling in loudness ("how loud is it?") we need 10 dB more acoustic intensity, which requires a
ten-fold increase in power. This gets into the realm of very large numbers very quickly.
- Differences of a few watts, or even tens of watts, unless we're talking about very low level output (1-2W amplifiers), are usually inconsequential. Having an AVR that produces 100wpc into stereo, but only 50wpc into five, is not a "bad" thing - it likely won't even be noticed. However, having an AVR that produces 100wpc into mono, but only 5wpc into five, is a terrible thing. Both exist.
- If your speakers are very sensitive (efficient), they need less power to create a given acoustic intensity. For our purposes, this means they get louder. Conversely, they require less power to get "as loud" as some less efficient speaker. If you have very efficient speakers (Klipsch Reference are a great example of this) you generally don't require anywhere near as much power as average efficiency speakers (Yamaha Soavo are a great example of this). This doesn't speak to sound quality or any other factor, just power in-loudness out.
- Target loudness is another good consideration. Aside from causing hearing damage at absurd levels (90 dB+), we should be concerned with output in terms of being able to approximate a reference level (which is generically, 85 dB continuous (observed from the listening position) for all channels, with the capacity of 20 dB peaks, and 105 dB for the LFE channel (this is higher because our hearing is not linear - lower frequencies have to be more intense to sound as loud)). If you're only sitting 3-6 ft from your speakers, you can probably accomplish 85 dB with most speakers with less than 1W in, and then your 100W amplifier can provide the required 100-fold increase (for the 20 dB gain)). Even if the amplifier cannot provide 100W CACD (Continuous All Channels Driven), it potentially can provide it for one or two or three channels as a peak. Remember that we don't listen to sine-sweeps (which is how CACD is measured), we listen to dynamic content that doesn't try to drive every channel at 0 dBfs until the amplifier shuts down.
Adding an external amplifier makes a lot of sense in a few cases:
- Support for very low impedance speakers.
- Support for very efficient or inefficient speakers. Inefficient speakers require more power, or a different gain structure (a more sensitive amplifier), efficient speakers may require a lower noise floor.
- Other considerations, such as aesthetic reasons (desire of another amplifier, or use of a tube amplifier, for example), multi-zone installations, or additional features (amplifiers with A/B terminals, for example).
We can look at a few receivers around your price range, and a few over, to get an idea of what power can cost. And yes, this is entirely ripped from the post linked in my signature.
http://www.hometheater.com/content/s...-labs-measures (what we absolutely don't want to see - there's so little power available that headroom does actually go out the window in this situation; 1-3W input will probably get you the 80-90 dB output, but what about the 10 or 100 fold power increase for dynamic peaks?)
http://www.hometheater.com/content/s...-labs-measures (what we absolutely do want to see)
http://www.hometheater.com/content/i...-labs-measures (what we absolutely do want to see)
http://www.hometheater.com/content/a...-labs-measures (for the price, what we absolutely do not want to see)
http://www.hometheater.com/content/p...-labs-measures ("average" - this is roughly what people are getting at in terms of midrange equipment)
http://www.hometheater.com/content/s...-labs-measures (actually outperforms more expensive equipment in terms of ACD - cost/brand name can't always be used as an indicator of performance)
http://www.hometheater.com/content/y...-labs-measures ("average")
Some further reading about the perception of loudness; amplifier output, sensitivity, and power; and SPLs:
http://trace.wisc.edu/docs/2004-About-dB/
http://audiokarma.org/forums/showthread.php?t=58829
http://myhometheater.homestead.com/splcalculator.html (you can figure out theoretical output based on speaker efficiency and amplifier power with this toy)
http://www.physics.mcgill.ca/~guymoo.../lecture11.pdf
http://www.butleraudio.com/damping1.php
Regarding the impact on the built-in amplifier - generally the internal amplifiers are disabled (either turned off or simply fed no signal) when external amplifiers are connected. This usually does little for power consumption (unfortunately), although power consumption on most AVRs at idle is low enough to not be a concern (even 100W is not really problematic; if you're concerned about your energy footprint (or bill), replace a few fixtures with CCFL or LED bulbs or line dry your clothes a few times a month).
Some AVRs (nothing you can buy currently, at least that I know of) will allow you to use both their internal and an external amplifier at once. I have no idea as to why you'd want to do this, but as long as you don't connect both amplifiers to the same speakers (more to the point: as long as they aren't connected TOGETHER), you shouldn't have any problems.