When do you need an amp vs. Home Theater Receiver?

[mechadsey]

I am thinking of upgrading to 685 series from my bookshelf 603's. Right now I have a Denon 2807 receiver with an output of 110 watts per channel.

I am confused overall about what a pre-amp and amp do that an AV receiver does not.

[Tweir]

When you step into floorstanding speakers would be a time to get an amp. With bookshelf speakers they are a pretty easy speaker to drive as opposed to the complexity of a floorstander. A friend has the 685's in a bi-amp mode with a denon avr2809 and it sounds way to good for what it is. I am not a fan
of amps on smaller speakers unless you have an 805 surround system all the way around but with this system the speaker still dip to 4ohms or less. Not many receivers can do all channels driven with a 4om load at each channel.

[WI Rotel]

WHen you use inefficient speakers.
The size of the speakers is not important its their efficiency, a king kong speaker with an efficiency of 95 db/1 watt is easier to drive than a bookshelf that has an 86db/1 watt efficiency. Compound that with a multiple speaker setup and soon no receiver in the world can handle the setup at high volumes for any amount of time without overheating ar shutting down. Thus keep and eye on a speaker's minimum impedance and efficiency. Unfortunately the impedance ratings are very often misleading instead of giving you a minimum nuber they give you and weighted average rating A good example is the XT4 though they are "rated" at 8 ohms they can go down to 3.1 a current that essentially no receiver in the market can push when the speakers are used as part of a multichannel setup since the combined impedances could reachsignificantly lower still.

[BWLover]

I drove the 683's with my RSX-1058 and it was good. Its for sale http://www.canuckaudiomart.com/detai...rotel_rsx1058/

[kmcheng]

There are also things that a pre-amp won't do, but a receiver will do.

An important function that the receiver does is decoding the audio tracks on DVD (or audio signals from the cable box). A pre-amp is almost always pure-analog in function and will not decode the Dolby Digital or DTS tracks for you.

I believe the 685 is on the borderline in terms of efficiency. If you are not playing your speakers very loudly, you probably can get by with a receiver.

[emig5m]

After driving my Yamaha into protection mode for the third time with the 683's I said to myself it was time for a real power amp. The Yamaha didn't sound bad on it's own, extremely good for a lower priced receiver, but it wasn't exactly sufficient for driving the 683's to their full potential either (full range no sub).

On the flip side, I've driven my 685's full range with the poweramp, and boy those things take the power of the Emotiva XPA-5 no problem! Those little bad boys will play loud and clear with the poweramp! At first I was afraid I'd be greatly overpowering the little 685's, but to my surprise they can handle a full on separate power amp no problem! I get a feeling that B&W underrates their speakers power handling, lol, because from my point of view they easily handle more than what their specs say.

[beden1]

I drove the 683's with my RSX-1058 and it was good. Its for sale http://www.canuckaudiomart.com/detai...rotel_rsx1058/

So good, you're selling it?

[BWLover]

as you can see on my signature i have upgraded
↓↓↓↓

[hifiguymi]

I think you have your model numbers mixed up. The DM603 is a floorstanding speaker and the 685 is a bookshelf. Could you tell us again what you have now and what you are upgrading to?

Eric

[mechadsey]

Whoops. I have DM 601 S3's (4 of them). Will be upgrading to 683's (floor standing right?)

Thanks

[hifiguymi]

That makes more sense.

As for your original question, a receiver is a preamp, amp, and tuner in one chassis. The preamp is what handles the source switching, surround processing, tone controls / EQ, and volume control. The amp is what runs the speakers and the tuner is the radio.

As for why would you want separates, performance. The AVR-2807 you have will work just fine with the 683 so I don't think you would have to upgrade. Those speakers are very good in the midrange (in my opinion) and will show off upgrades in your electronics however. I think you could go up to the CM7 and get good results with the AVR-2807. If you were to go to something like a Rotel RMB-1565 (I'm a B&W, Rotel and Denon dealer so I'm familiar with the products you have) which is the smaller of the two multi channel amps they have, at 100 watts x 5, it would be an improvement for sure. As good as A/V receivers are in that price range they don't have the same quality amp section you will get from a separate amp. That receiver has preamp outputs so you could add an amp to it, and just not use the amps in the receiver, to upgrade your system a piece at a time. You can add a separate preamp down the road and get another improvement.

With all of that said you can upgrade to a better receiver as well, like the AVR-4310CI and up from Denon, and make an improvement in amplifier quality. A Rotel RSX-1560 would be a nice upgrade as well. Separates give you more flexibility long term and overall better performance, you just have to decide if the investment is worth it to you.

Eric