Are THD ratings on Yamaha receivers accurate?

[nick_danger]

Yamahaluver, I'm looking in your direction. The reason I'm asking is that previous Yamaha receivers, like the now discontinued 5790, showed the THD rating to be .03% @ 1KHz (if memory serves). The new 5890 claims a THD of 0.7% @ 1KHz! What's with the dramatic spike in THD? Are these THD numbers considered to be snake-oil most of the time? I know it can be difficult to tell in some cases, but going from .03 to .7 is huge increase!

 

[Francious70]

Yea, but anything under 2% is inaudible anyways. The "dramatic" increase dosen't really matter.

Paul

 

[annunaki]

Rating at a higher THD makes the unit appear to have more power. Say the receiver does 80 watts per channel at .03% thd but does 100 wats at .7% thd. The higher power # is easier to sell. Chances are, that the receiver probably does 10 less watts or so at .03% thd as opposed to it's .7% thd rating.

 

[Buckeyefan 1]

Where did you find this info? There are no manuals on the new 5890 at Yamaha's website. I would imagine it's a typo. UK and European countries usually rate their amps at 1kHz, while the US rates power at 20Hz to 20kHz.

Just found it. Right of Best Buy's website. It hasn't changed one bit:

www.bestbuy.com/site/olspage.jsp?skuId=7067345&type=product&productCategoryId=cat03031&id=1108125946150

 

[nick_danger]

Rating at a higher THD makes the unit appear to have more power. Say the receiver does 80 watts per channel at .03% thd but does 100 wats at .7% thd. The higher power # is easier to sell. Chances are, that the receiver probably does 10 less watts or so at .03% thd as opposed to it's .7% thd rating.

OK, the 5890 manual isn't available, but the 5790's is. It states that the THD for minimum RMS at 20-20,000Hz @ 8 Ohms @ 110Wx7 is 0.04%. At maximum power @ 1,000Hz, THD is 10.0% @ 8 Ohms @ 165W. Then there are even more ratings, like DIN for the U.K. that says 0.07% THD for 1,000Hz @ 4 Ohms @ 170W. There's a whole ton of different ratings to go by.

I need edumacate myself on all these Hz, Ohms, Watts, and distortions...

 

[Buckeyefan 1]

All those ratings are the same. Amazing how they differ at different ohms, THD, kHz, etc... Different countries require different standards. In the UK, all their equipment runs on 220V. That changes things a bit. A lot of their speakers run at 6 ohms, not 8. I wouldn't get too caught up in it. Generally, you get what you pay for in terms of electronics. Stick with the better brands, and try to stay near the the mid to top end of the equipment. Look for sales or end of year models. Equipment doesn't change all that much year to year.

 

[MarkH]

The HTR Yamaha range is generally rated at 1kHz, while the more traditional RXV series is 20 - 20kHz. This is pretty much universal no matter which country you're in.

 

[annunaki]

OK, the 5890 manual isn't available, but the 5790's is. It states that the THD for minimum RMS at 20-20,000Hz @ 8 Ohms @ 110Wx7 is 0.04%. At maximum power @ 1,000Hz, THD is 10.0% @ 8 Ohms @ 165W. Then there are even more ratings, like DIN for the U.K. that says 0.07% THD for 1,000Hz @ 4 Ohms @ 170W. There's a whole ton of different ratings to go by.

I need edumacate myself on all these Hz, Ohms, Watts, and distortions...

Here is an audio terms page:

http://www.electronixwarehouse.com/education/glossary.htm