Question about Receiver Power

[volcanotheatre]

I'm trying to decide how to choose a new HT receiver. How much weight do I put on the Watts per channel? It will be going in a decent sized basement.

Right now I'm torn between a Yamaha RXV 657 (100wpc) and a Harman Kardon av 335. The Hk has only 55wpc. I'm looking at Definitive Audio Promonitor 100 speakers to add to the reciever.

Need some help from some of the local Pro's!

Thanks
Chris

[EdwardGein]

Watts do make a difference As somebody said here some companies overstate their actual wattage. To me personally, from having a Denon 3801 receiver which is supposidly pretty acurate on its 135 watts per channel, softer passages of music have alot more clarity and richness than say something that was coming from my JVC receiver which advertised itself as 100 watts per channel. I'd do a google search on the receivers you are contemplating and read their reviews to get a better feel.

[drseid]

I'm trying to decide how to choose a new HT receiver. How much weight do I put on the Watts per channel? It will be going in a decent sized basement.

Right now I'm torn between a Yamaha RXV 657 (100wpc) and a Harman Kardon av 335. The Hk has only 55wpc. I'm looking at Definitive Audio Promonitor 100 speakers to add to the reciever.

Need some help from some of the local Pro's!

Thanks
Chris

Either one of those receivers will have absolutely no problem driving the ProMonitor 100s...

I actually drive the ones I use in my largish office to *plenty* loud levels with a little Sonic Impact T-Amp that puts out about 5-8 watts per channel.

HK tends to be conservative with their power ratings, and Yamaha is pretty honest too. Since the ProMonitors are 89db efficient into 8 ohms, and do not have any significant impedance dips, either will work nicely.

---Dave

[kexodusc]

You can bet the Yamaha will put out it's rated power in 2 channel stereo mode. Where H/K's specs about watts/channel will differ is the real power it is capable of delivering to 5 or more channels simultaneously. Rest assure the H/K will pump out 55 watts into 5 channels at the same time. I would expect the H/K to have a bit more power after that too.

The Yamaha specs I've seen on the RX-V650 (the predecessor to the 657) put it down around the 48-52 watt area, a bit lower than the 100 watt X 7 the specs mislead you with. 100 X 7 does not mean 700 all at once. It means each channel can be fed 100 watts if the demand is there. Useful but not the same as 700 watts.

The question now should be does that 5-7 watts/channel difference matter to you? IMO, if it does, you shouldn't be considering either of these receivers, you should be looking at something with even more power.

Both will drive your speakers fine, to extremely loud levels, and at maximum, they'll perform similarly, with the H/K likely having just a tiny bit extra headroom at the end.

For all intents and purposes, I think you should consider other aspects, as the power itself isn't significantly different between these units. Does one sound better to you? Are there better processing features, setup options, bass management options, inputs, outputs, etc, on one over the other? What about quality? H/K seems to have fixed the few issues they had a few years back and have re-established themselves as one of the favorites in this price range, and Yamaha has always been considered second to none when it comes to build quality. Might not be too much difference there either.

Just a few things you should consider.

[PAT.P]

Kexodusc I agree with you that is receivers would have no problem .I just bought the Yamaha HTR- 5760 for this reason and the feature .Can you explain the dynamic power ( IHF) factor 8/6/4/2 130/165/195/240 W . and if I wanted more power I would probably add a multy -channel amplfier. I have 9 speaker and 2 sub connected to this receiver and seem powerfull enought so far .Pat.P

[kexodusc]

I believe the dynamic power rating is just another specification standard. Every receiver/amp will output a lot more power than the specs say, it's just that the distortion goes up as the power increases. If you used Sony's Sears ratings of watts RMS at 10% distortion, I wouldn't be surprised if the Yammie and H/K hit 200 watts/channel. It'll sound like crap, but thump along.
Truth be told even hard-core audiophiles that are anti-science, anti-engineering will tell you that 0.05% distortion is stupid low, because studies show humans are pretty much incapabale of hearing THD as high as 1% (and I've seen numbers like 2% or 5%, but that's pushing it IMO). A lot of kilo-bucks tube amplifiers have distortion this high and sound terrific.

Pat, I'm a bit different than a lot of people here on this board because I'm a believer that you should by power for your needs + modest flexibility, not just aim for the most power you can have.
I've owned 200 watt amps in the past, and to me they didn't sound as good as the smaller watt units (mind you NAD was the only brand I owned for reference, maybe that was why?).

I don't know what kind of speakers you have but most have sensitivity in the 88 dB range now. 1 or 2 watts will be pretty f'n loud. With 40 watts/channel of available power before distortion starts to dip, that leaves an ample amount of headroom. You'll have no problem hitting theater levels.

In my own opinion, higher priced amps have better components in them, and sound better not because they have more power (which you often get as the price goes up) but because they're just higher quality units all around.

I have two 60 watt Adcom amps and an 80 watt Rotel (or Audiosource, depending on my mood) plugged into my RX-V1400. I think that thing was rated to 110 watts (55-60 watts or so all channels driven). The power amps have more real power available for the occasions I do like to hit 90 or even 100 dB, but just sound better IMO. But I get by in my 480 square foot room with this level of power, so 200 watts/channel is unecessary for me.

Power output ratings only tell you half the story though. Most a/v receiver power supply units are pretty taxed as unit starts outputing power to 5, or 7 channels. For short bursts it's fine, but if you really start demanding that level in 7 or 9 channels in your case, you might want to start thinking about more external power.

To me there's more than just higher wattage to consider in amplifiers.

[kfalls]

There is a lot more to amplifier than wattage. Many factors come into play. How much heat can the outputs dissipate? Discrete outputs are usually able to dissipate more heat than IC outputs (Yamaha has discrete outputs) and are less likely to "blow". How much heatsink area do the outputs have? How robust is the power supply, large transformer, storage capacitors, regulators? If the power supply can't provide enough power you'll get clipping and distortion. Look at the dynamic headroom spec. This will tell you how much more power is available above the rated output spec for instaneous peaks. The weight of the receiver will also tell you a lot about its power supply. With the exception of high-end receivers which like to use 1/2" faceplates, the weight will tell you if the unit has a large transformer and adequate capacitance and heatsinks. If the receiver says it has 100WPC and wieghs half that of another 100WPC receiver, you want to look closer at the specs especially the distortion. The fact that an amplifier gives specs for 8,4,2,ohm outputs should be an indication it's capable of higher current than those who don't.

[kexodusc]

In todays age of digital switching and light weight power supply units, receiver weight really doesn't tell us as much as it use to. Dramatic differences you can assume pretty safely that the heavier receiver is better, but a few lbs here and there between brands doesn't tell us anything anymore.

[PAT.P]

Thanks Kexodusc and K Falls for input . Kexodusc my speaker are Dahlquist QX9 for front tower 6ohm nominal 93db @2.83 v,1m / my surround areDahlquist Qx-25RA 6ohms and Im using for now two Paradigm stylus cc for the front pressence speakers 90db , the centre is a JBL EC25 8ohms 90db .My sub are PS -1000 discrete amplifier and the other sub is a Dahlquist QX100SA 8" Digital Bash .My other tower is a 3 way bought at Radio Shack 10 years ago Genexxa I know their 8 ohm but cant find any spec on this one (just know they could take all the power ) Thansks Pat.P

[kexodusc]

93 dB @ 2.83 v, 1m is pretty efficient, safe bet you're getting at least 90-91 dB with 1 watt at 1 meter distance.
Still, don't rule out the benefits of quality amplification. With 9 speakers connected to your receiver it certainly wouldn't hurt.
Just use common sense, if anything starts to sound bad, turn it down.

[PAT.P]

Kexodusc Thanks again never brought receiver at 20db and this is plenty loud in a room 26x16.Might save up for an multi-channel amp but for now wont push to the limit .Pat.P

[HAVIC]

The Yamaha specs I've seen on the RX-V650 (the predecessor to the 657) put it down around the 48-52 watt area, a bit lower than the 100 watt X 7 the specs mislead you with. 100 X 7 does not mean 700 all at once. It means each channel can be fed 100 watts if the demand is there. Useful but not the same as 700 watts.

kexodusc so are saying that even though my yamaha rxv2500 manual says

Minimum RMS Output Power
(0.04% THD, 20 Hz - 20 kHz, 8Ω)
Front: 130W + 130W
Center: 130W
Surround: 130W + 130W
Surround Back: 130W + 130W

that it is not 130x7 all at once because I feel that is VERY misleading.

Also these specs are for speakers a 8 ohms. I have six ohm speakers with almost identical specs to Pat P. I have PSB Image series T65 towers.
Approx how many watts per channel would the reciever put out at 6 ohms then?

[markw]

Just use common sense, if anything starts to sound bad, turn it down.

... and QUICKLY!

FWIW, rule # 2 would be "When kerfutzing with cables or interconnects, power down everything, and I mean everything, connected to them." It's cheap insurance.

[kexodusc]

kexodusc so are saying that even though my yamaha rxv2500 manual says

Minimum RMS Output Power
(0.04% THD, 20 Hz - 20 kHz, 8Ω)
Front: 130W + 130W
Center: 130W
Surround: 130W + 130W
Surround Back: 130W + 130W

that it is not 130x7 all at once because I feel that is VERY misleading.

HAVIC:
That's exactly what I'm saying. In reality, the real power with all 7 channels simultaneously driven is probably 40%-50% of that number.

But before you feel mislead, you have to understand the history behind that. Briefly, old stereo receivers/amps were rated with 2 channels driven. When multichannel receivers came along the industry recognized that most multi-channel sources rarely use all 5 speakers at similar levels during playback. So rating it with all 5 or 7 channels driven wasn't really a good indicator of the performance of these units either.

You can say that NAD, H/K etc, who use the "all channels driven" method are being more honest, but they're not. Just a different measurement. Your receiver is capable of sending up to 130 watts to each of its 7 channels, sometimes 2 at once.

And before you get upset, you have to realize that the loss in power available with all channels driven isn't going to make a big difference. 99% of people would never drive their receivers close to maximum power anyway and wouldn't know otherwise.

Also these specs are for speakers a 8 ohms. I have six ohm speakers with almost identical specs to Pat P. I have PSB Image series T65 towers.
Approx how many watts per channel would the reciever put out at 6 ohms then?

I really don't know, it depends on more than just the drop in impedance. Save bet is well over 150 watts. For all intents and purposes, it probably wouldn't drive your speakers 1 dB louder though or provide much more headroom.

And let's be honest here. Even if your receiver did ouput all that power simultaneously, the real-world benefit would only a tiny bit more output and headroom ability anyway. The loss isn't as great as many make it out to be.

Power is nice to have, and more is usually better, but you should always consider increasing power by a factor of 2, IMO.