Question Does a loud source mean the amp uses more power?

Discussion in 'AV Receivers & Amplifiers' started by PorkPieCat, Jun 27, 2015.

  1. PorkPieCat

    PorkPieCat
    Standard Member

    Joined:
    Apr 4, 2012
    Messages:
    37
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    6
    Ratings:
    +0
    Source is a PC. If the volume setting is increased in software, the speakers get louder without having to increase the amp volume. I'm wondering if this increases the power draw from the amp to the speakers?

    It's weird because my 50wpc channel amp seems to be driving my 100w speakers to really loud volumes with the gain dial at about 10%, and I'm worried that maybe my PC is such a loud source that the amp is being driven harder than it should, if that makes sense.

    PC volume is at 100%, which is +0db. The sound card is fairly high end and apparently doesn't distort at all at this setting. I'm keeping volume at 100% because apparently bitrate is reduced at lower volume, and so is SNR.
     
  2. dante01

    dante01
    Distinguished Member

    Joined:
    Mar 5, 2009
    Messages:
    46,566
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Ratings:
    +11,225
    No, the greater the source signal level then the less amplification is required by the amp to attain a measured level post amplification. The same amount of power is applied in relation to the volume dial irrespective of the signal level coming into the amplifier, but you shouldn't be inputting an amplified signal into any amplifier's fixed line level input. I'm pressuming the source signal is a low level variable signal? If so then ensure the level isn't so high as to cause distortion. Having too high a pre amplified signal can result in distortion. Unwanted distortion can be caused by a signal which is "too strong". If an audio signal level is too high for a particular component to cope with, then parts of the signal will be lost.

    You may find this article of interest:
    Ins & Outs Of Gain Structure
     
    Last edited: Jun 27, 2015
  3. PorkPieCat

    PorkPieCat
    Standard Member

    Joined:
    Apr 4, 2012
    Messages:
    37
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    6
    Ratings:
    +0
    I'm not sure what a low level variable signal is, but it's line level from the RCA connectors of my sound card. It's not amplified, and the gain setting is digital in nature.

    The source is at +0db. It can be set to stereo direct mode, which is the same volume. I can't personally detect any distortion, and like I said the sound cards is meant to have the best SNR and lossless output only at 100%. I was only worried that the amp was being overloaded, but you've put me at ease, really. Thanks for the help.
     
  4. dante01

    dante01
    Distinguished Member

    Joined:
    Mar 5, 2009
    Messages:
    46,566
    Products Owned:
    1
    Products Wanted:
    0
    Trophy Points:
    166
    Ratings:
    +11,225
    It would be more normal to use a "fixed line level" signal (your stereo direct mode) as opposed to a variable line level signal from a source to an amplifier. There's no real advantage to outputting the signal at higher levels than actually needed and as I said, this can cause distortion if you set the level (gain) too high. The quality of the sound card and or the amp has no bearing upon this and it to do with over saturating the signal. If not hearing any distortion though then there's no issue with what you are doing.

    Ever wonder what the VU meters are used for on mixing desks? The engineer uses them to ensue the signal doesn't go into the red and this is used to set the levels being recorded without introducing distortion. You've no visual indication of the signal level going into your amplifier so you have to play it by ear.
     
    Last edited: Jun 27, 2015
  5. PorkPieCat

    PorkPieCat
    Standard Member

    Joined:
    Apr 4, 2012
    Messages:
    37
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    6
    Ratings:
    +0
    I mean, I'd use stereo direct mode all the time if I could, but with the way Windows works, it only kicks in when a program "takes control" of the sound card. So in my case it works in specific music players for example. But I've done comparisons with stereo direct mode on and off on those players and the volume when in fixed stereo direct mode is the same as the 100% setting when in variable mode, so I figure it's more or less the same thing.
     

Share This Page

Loading...