Connect with us

Adjustable amplifier rails.

Discussion in 'Electronic Design' started by Michael, Nov 20, 2003.

Scroll to continue with content
  1. Michael

    Michael Guest

    I have an idea, but i'm not an expert on switchmode power supplies so
    I'd like to run it past you guys.

    I wish to make a portable high powered stereo for camping trips using
    a car audio amplifier (2x60W), a lead acid battery and either a car
    head unit or cd walkman.
    These amplifiers use a switchmode supply which generates approx +/-
    30V rails.

    I was thinking, I could have adjustable rails, with a slow decay (say
    3-4V per min) and a fast attack which would be triggered by a clipping
    sensor on the amp.
    This would increase the battery life at lower listening levels, where
    30V of headroom would waste a lot of power.

    Would there be a problem with dropping voltage when the transformer
    is wound to create 30V rails, providing the PWM circuit can generate
    short enough pulses?




    Michael.......
     
  2. John Larkin

    John Larkin Guest

    Geez, just what Yosemite needs.

    John
     
  3. The switching power supply in most car audio amps isn't variable by
    much, if at all. Consider one of the Class D variations for efficient
    power.
     
  4. DaveC

    DaveC Guest

    LOL... I thought I was the only one in the campground who longed to hear
    *only* the crickets and the surf...

    Leave the damn stereo at home!!!

    There. How I've longed to yell that from my tent.
     
  5. dont worry, looks as if he is in Oz.........



    thanks

    martin
     
  6. A switchmode amplifier doesn't waste power with higher rails,
    or not much anyway.
    As the others said, it is an almost infinitely bad idea to
    take the stereo for camping. Stay in the city and cut the lawn.
    Brrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr...

    Rene
     
  7. Why not just cheat and add another ganged element to the volume pot. Use
    the position of the volume pot to set the power supply voltage reference.
    Judiciously set up, this should get you 99% of the way there.
     
  8. Mike Page

    Mike Page Guest

    Buy a big enough solar panel and you won't have to worry too much about
    battery life. That is, if the weather in Oz holds up ;-)
     
  9. N. Thornton

    N. Thornton Guest

    Hi. Certainly this would significantly improve the efficiency of the
    class B amp. If you use a class D amp instead you get even higher
    efficiency.


    Regards, NT
     
  10. Linear

    Linear Guest

    ......
    I was thinking, I could have adjustable rails, with a slow decay (say
    3-4V per min) and a fast attack which would be triggered by a clipping
    sensor on the amp.
    This would increase the battery life at lower listening levels, where
    30V of headroom would waste a lot of power.
    .....
    Take a look at the AD8393 on the Analog Devices Web site analog.com.

    It functions like you describe, but at lower voltages.
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-