What power? - AVS | Home Theater Discussions And Reviews
Baselworld is only a few weeks away. Getting the latest news is easy, Click Here for info on how to join the Watchuseek.com newsletter list. Follow our team for updates featuring event coverage, new product unveilings, watch industry news & more!


Forum Jump: 
 
Thread Tools
post #1 of 9 Old 12-12-2012, 08:19 AM - Thread Starter
AVS Special Member
 
karlsaudio's Avatar
 
Join Date: Nov 2009
Location: Maple Grove, MN
Posts: 1,882
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 122 Post(s)
Liked: 31
I get the power ratings now days on recievers and AVRs being very optomistic sometimes but, I am currious about two older recievers I have. The first is a 1984 vintage Akai unit that I know puts out 40 wpc. On the back panel, it states total wattage usage as 120. The second is a slightly newer Pioneer unit that I think was rated at 50 wpc and the wattage usage is 190! So, where does the extra 40 and 90 watts respectively go in these units? Thats a lot! Or were these under rated?

Sounds good!
karlsaudio is offline  
Sponsored Links
Advertisement
 
post #2 of 9 Old 12-12-2012, 10:47 AM
AVS Special Member
 
Ethan Winer's Avatar
 
Join Date: Apr 2003
Location: New Milford, CT, USA
Posts: 5,757
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked: 139
The difference is dissipated as heat. But amplifiers and receivers don't draw the full power from the AC outlet all the time.

--Ethan
Ethan Winer is offline  
post #3 of 9 Old 12-12-2012, 12:54 PM
AVS Special Member
 
Selden Ball's Avatar
 
Join Date: Jan 2001
Location: upstate NY
Posts: 8,644
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1294 Post(s)
Liked: 690
Different companies use sufficiently different designs for their receivers that it's difficult to guess where the additional power is being used. The additional power might be available to the speakers, or it might be dissipated in the receiver's other circuits.

Selden

Marantz SR7009+MM9000/Atmos 7.1.4 (FH+TM:DefTech PM1000)/LCR+TM amped
Selden Ball is online now  
post #4 of 9 Old 12-12-2012, 01:00 PM - Thread Starter
AVS Special Member
 
karlsaudio's Avatar
 
Join Date: Nov 2009
Location: Maple Grove, MN
Posts: 1,882
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 122 Post(s)
Liked: 31
I can understand maybe 10-20 watts but up to 90 (or more!) seems a lot to me.

Sounds good!
karlsaudio is offline  
post #5 of 9 Old 12-12-2012, 01:41 PM
AVS Special Member
 
Selden Ball's Avatar
 
Join Date: Jan 2001
Location: upstate NY
Posts: 8,644
Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 1294 Post(s)
Liked: 690
You need to look at the details of how they quote the amplifier power. Too often older receivers were rated with their "dynamic" power (thus needing only a small power supply) and not continuous, full bandwidth, all channels driven simultaneously (thus needing a much more robust power supply).

Selden

Marantz SR7009+MM9000/Atmos 7.1.4 (FH+TM:DefTech PM1000)/LCR+TM amped
Selden Ball is online now  
post #6 of 9 Old 12-12-2012, 02:23 PM
AVS Special Member
 
mcnarus's Avatar
 
Join Date: Nov 2007
Posts: 6,219
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 150 Post(s)
Liked: 351
Quote:
I can understand maybe 10-20 watts but up to 90 (or more!) seems a lot to me.
Just because an amp is rated at 100 wpc does not mean it cannot deliver more than that.The "official" power rating is a convention meant to allow apples to apples comparison of amps on some measure. A full power spec has several conditions attached to it, including bandwidth and distortion, not to mention the continuous power requirement. Relax any of those conditions, and the amp may well deliver more than the advertised power.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

mcnarus is offline  
post #7 of 9 Old 12-12-2012, 04:14 PM
AVS Special Member
 
JHAz's Avatar
 
Join Date: Mar 2009
Posts: 4,201
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 172 Post(s)
Liked: 194
As I understand it, you could take the same amp and swing the power requirement at least that far just by changing the bias to the out[ut transistors. Heat em up deeper into the class A end of AB and you use more power, and get less clean headroom as an added "bonus." (this from a guy who prefers his guitar amp's tubes biased moderately hottish 'cause it sounds so good when you turn up stupid loud).
JHAz is offline  
post #8 of 9 Old 12-13-2012, 05:55 AM
ap1
AVS Special Member
 
ap1's Avatar
 
Join Date: Apr 2007
Location: New Jersey
Posts: 2,254
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 16 Post(s)
Liked: 19
If you want good estimation of how much power you can get from a receiver taketotal power consumption value (which has to be correctly stated by law), multiply by 0.6 (which is average efficiency of conventional AB class amplifier) and divide to number of channels. Independently published measurment results are usually close to the resulting value.
ap1 is offline  
post #9 of 9 Old 12-13-2012, 09:17 AM - Thread Starter
AVS Special Member
 
karlsaudio's Avatar
 
Join Date: Nov 2009
Location: Maple Grove, MN
Posts: 1,882
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 122 Post(s)
Liked: 31
Quote:
Originally Posted by ap1 View Post

If you want good estimation of how much power you can get from a receiver taketotal power consumption value (which has to be correctly stated by law), multiply by 0.6 (which is average efficiency of conventional AB class amplifier) and divide to number of channels. Independently published measurment results are usually close to the resulting value.

Using this formula, that puts the Akai at 36 wpc and the Pioneer at 57 wpc. Which is kind of close to their published ratings.

Sounds good!
karlsaudio is offline  
Sponsored Links
Advertisement
 
Reply Audio Theory, Setup, and Chat

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page


Forum Jump: 

Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off