View Full Version : Yamaha AX-900 - Confused Watt rating?


mufster
07-29-2009, 07:17 AM
Hi all. Just picked up a very nice amp for my sons bedroom. It's a bit of a beast and I had previously looked on Google for the specs. I downloaded a user manual that says it total power is 550W. I've seen a piccy on Google of one that said 600W and mine says 250W. Incidentally, this 600W version had a different voltage selector to mine. That one was a switch 220v - 240v and the one on mine is round and has all the voltages from 110v - 240v. So I'm really confused now. Did they make them in different Watts or were they manufactured in different countries and it's how the voltage is displayed? At the least I thought it would say 550W on the back, as that is what the manual says.

Internally, it looks exactly the same as this one: http://www.audiokarma.org/forums/showthread.php?t=63460

Can anyone shed some light on my confusion please?

Thanks.

Audio_Works
07-29-2009, 07:27 AM
If your unit has 2 filter caps of 2200uf at 71V each, 250W power consumtion is too small. Can u post a picture of the back of the amp?

mufster
07-29-2009, 08:55 AM
Here are some photo's of the unit, inside as well as outside.

And here is the other piccy I saw http://www.bilder-hochladen.net/files/big/a7cd-10f.jpg

mufster
07-29-2009, 09:09 AM
Here is the spec page from the manual. Granted, it is for the AX-900U but I uderstand the 'U' denotes USA model. So I can't see there being much difference in the stated Watts.

SRVDean
07-29-2009, 10:12 AM
That says that the RMS power rating is from 130 watts to 180 watts at 8 ohms.

71Challenger
07-29-2009, 10:41 AM
What you are seeing on the back panel is the power consumed to run the beast. The actual RMS power output rating to the speakers should be in the 130 watts/channel range.

Fantastic amplifier by the way.

rockin1150
07-29-2009, 10:49 AM
that is a very nice piece by the way~ cheers! gotta love those ol' black n green toshiba transistors... well I do anyway.

mufster
07-29-2009, 10:57 AM
Thanks for the replies everyone. Appreciate them. It does appear to be a nice amp, plus it's very heavy which always adds to that feeling of 'goodness'. My son was complaining the Marantz PM6010KI he was using "doesn't have enough bass" so I've let him 'borrow' this Yamaha. I bought it to use as a second to my Sansui while I send it away to have it's 25 year service. My son is only 9 and he's told me that when I send my Sansui away I can use the Marantz until I get it back. This isn't what I had in mind. This could get ugly...

Audio_Works
07-29-2009, 12:17 PM
hmm on the pannel says 250W but i doubt that is the consumed power. As you can see the output power is 130Wpc so considering we live on Earth u cant consume 250W and deliver 260W (or more on 6ohm). In the manual says power consumption is 550W thats more like it. I belive the 250W is for the outlets on the back panel. Do u have mains outlets to connect other equipment like cd players on the back panel?

mufster
07-29-2009, 12:43 PM
Do u have mains outlets to connect other equipment like cd players on the back panel?

Here's a picture of the inputs, as requested.

whoaru99
07-29-2009, 12:47 PM
Back panel power input/power consumption ratings are seldom listed at maximum audio power output on consumer audio gear.

The same component built for different regions of the world will have different input power/power consumption ratings on the back panel based on the regulatory requirement/agencies of the region.

For example, the service manual for my Yamaha M-80 amps lists four considerably different back panel input power ratings depending on intended market region.

So, the bottom line is that you are not cheated out of any power. It's merely different because of different regulatory standard/requirements.

mufster
07-29-2009, 01:06 PM
Here is the voltage selector switch. I've not seen this version on any of the other AX-900's that I've seen so far. For example there is one for sale here http://www.audioscope.net/yamaha-ax900-amplifier-p-1145.html and that has a totally different voltage selection switch and states the power as 600W.

mufster
07-29-2009, 01:09 PM
Back panel power input/power consumption ratings are seldom listed at maximum audio power output on consumer audio gear.

The same component built for different regions of the world will have different input power/power consumption ratings on the back panel based on the regulatory requirement/agencies of the region.

For example, the service manual for my Yamaha M-80 amps lists four considerably different back panel input power ratings depending on intended market region.

So, the bottom line is that you are not cheated out of any power. It's merely different because of different regulatory standard/requirements.

Thanks for clearing that up. I was considering that I'd bought either an early or later version where the power wasn't as high as the others. But what you said makes a lot of sense and I understand now that I've got a 'normal' one.

TLCW
03-21-2011, 05:14 AM
The output of Yamaha AX-900 -independent of U (USA) version or not, the power output is 130W RMS / channel at 8 Ohm. will be 4 X 130 W = 520 W when at A+B .- maybe at bi-amp . For 6 ohm speakers would be 150W x 4 = 600 Watts.- which is close to the (max) rated power consumption of 600W.

whoaru99
03-21-2011, 06:42 AM
The watts the unit produces will be divided between A & B, not added together.