Originally Posted by Ovation
The Yamaha literature specifically states 2 channel for its power rating and it does meet those specs.
Yamaha does not list an all channel driven spec, so when tested in that fashion, it is not failing to meet its specs.
Some (NAD, for one) list their power output as all channel driven. However, when tested, their two channel output is usually higher than their all channel driven spec.
The result is Yamaha and others get slammed for not meeting their power specs (when they actually do as per the actual literature) and NAD and others get praised for meeting/exceeding specs. In reality, it is merely a matter of emphasis on which set of readings a company chooses.
Reading ALL the stated specs and looking at the reviews demonstrates that receivers tend to act as expected with amplification, as long as one knows what to look for.
I guess when they say 140x7..it could lead one to believe this is all channels driven. Though I have seen the AV publication that rated the A3000 at 66w with 5 channels driven
I agree with you...there are those units out there that rate their units as all channels driven ..and when tested in 2 channel they are typically benched higher than their manufacturers rating
I have an older Onkyo receiver that would be a prime example of that
Interestingly enough...I can understand why their can be some misunderstanding
Typically when one is shopping for separates..its very common for amp manufacturers to give their specs all channels driven...especially the mid to higher end manufacturers
My main listening area amp would be a prime example of that...Sherbourn
Rotel and Sunfire would also be examples
In fact I have seen all channels driven testing even higher than their manufacturer spec sheets
But I understand what you are saying...and that is why I typically wait for a testing from an AV publication to check the actual stats
Manufacturers...especially with receivers, can tend to be very "optimistic" with their rating vs what an AV testing lab gains from their testing proceedure
For a unit that will be used in multichannel mode significantly more than 2 channel...to me the all channels driven test is important