bi amp

Yes and no x, current limitations is what enables most to list them as 4 ohm capable. It's not necessarily indicative of the power supply, just how they go about handling the additional load.

That's more the case with entry-mid line receivers. TOP ones do have better power supplies and can probably drive a fairly efficient 4 ohm speaker to reasonable levels but still nowhere near what a separate amp is capable of.

Point being, stop worrying about the receivers power, and worry more about if it has preouts or not. Without them, your limited to what speakers you can run with.

Need more info, damping factor and slew rate.

avalanche wrote: »

How does this look for an amp? Looks to me 4 ohm capable since it almost doubles its power at 4ohm.

Dynamic Power per Channel (8/6/4/2 ohm 165 / 210 / 285 / 405 W

That's a deceptive spec as many like you don't understand it and think it's 4 ohm capable, heck it appears to be 2 ohm capable. The dynamic power rating simply means it can output that rating for less than a second or so, it is not continuous or as Nightfall stated, the wpc rating.

To re-enforce what Tonyb said about AVR's and 4 ohm ratings. Almost all AVR's rated for 4 ohms do so by LIMITING current, which is exactly what you don't want.

As for those Audioholic's videos/postings....you'd be best served by ignoring them unless you want to settle for mediocre.

Interesting discussion on amps.
Yes, this is copied from a yamaha 2040 which is near top of the line AVR.

I understand that continues power rating is good for comparisons but do we really need it when we play music?

Also the link shows that the yamaha 2000 has been tested to 4Ohm.

This graph shows that the RX-A2000’s left channel, from CD input to speaker output with two channels driving 8-ohm loads, reaches 0.1 percent distortion at 170.5 watts and 1 percent distortion at 189.3 watts. Into 4 ohms, the amplifier reaches 0.1 percent distortion at 236.1 watts and 1 percent distortion at 287.4 watts
Read more at http://www.soundandvision.com/content/yamaha-aventage-rx-a2000-av-receiver-ht-labs-measures#lG4fQKRQcJ3OzzDu.99

Good point Ken.

Many older, and certainly vintage receivers had some darn fine power supplies in them despite their power ratings in watts. An old Sansui or Marantz 60 watt'er had more power than todays 100 watt receivers easily.

Point being, watts is not the sole indicator of a good power supply, but it sure sells stuff which is why it has become the leading indicator to those who simply are not that in tune to the industry.

When it comes to power supplies and todays receivers, it's probably best, if you don't want to get in the weeds and think too much, to associate it with model lines within a brand. You can break it down into 3 categories....

entry level...which all brands will have the same weak power supply

mid-level- will be a tad better, but some will also include pre-outs to add power.

Top of the line- is where you'll find the best power supplies and gives you the best variety of speakers to use with them. All will have pre outs also.

Obviously, if your on a budget, the mid line option is best with pre outs. That way you can add more power should you find a deal on speakers that need some. Entry level is fine if you never plan on going larger than 8 ohm bookies or small 8 ohm floor standers.