Gentlemen,
After about a week of getting reacquainted with analog signal analysis and running through a whole set of batteries on my HP calculator I've come up with a NON-discrete class-D amp that should work well for my application. That application being a top-of-the-line subwoofer.
I'm about to start construction on the subwoofer, which will feature one of the new Adire Tumult 15" woofers (http://www.adireaudio.com/Home/TumultSeries.htm) in a closed box of about 35-liters. Of course with the Vas volume of the woofer, 266-liters, the F3 is around 100Hz and thus the drop-off is -12db/oct.
To compensate for that I use a simple filter that is the reverse of that curve, +12db/oct and hence will flatten the curve again. This principle is known as ELF or Bagend and is used by manufacturers such as Velodyne.
Of course the amplifier power needed is substantial, due to the +12dB/oct boost. For 110dB at 100Hz amp power is 50-watt, then at 50Hz > 200-watt and at 25Hz > 800-watt and so on. Obviously for efficiency and power handling reasons I want a class-D amp to power the sub.
I've been reading up on class-D amp design in the past week(s) and designed the following schematic by borrowing ideas from around the web, here at diyaudio.com, in application notes and at the German Hifi-forum.de website. What do you think, am I on the right track here? With a power supply of +/-80-volts and a 2-ohm impedance I should be hitting my mark of about 800-watt RMS right? And please let me know if there's any glaring errors in the schematic.
Class-D sub amp schematic
http://hardwareanalysis.com/images/articles/large/11520.gif
Looking forward to the (many) replies.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com
After about a week of getting reacquainted with analog signal analysis and running through a whole set of batteries on my HP calculator I've come up with a NON-discrete class-D amp that should work well for my application. That application being a top-of-the-line subwoofer.
I'm about to start construction on the subwoofer, which will feature one of the new Adire Tumult 15" woofers (http://www.adireaudio.com/Home/TumultSeries.htm) in a closed box of about 35-liters. Of course with the Vas volume of the woofer, 266-liters, the F3 is around 100Hz and thus the drop-off is -12db/oct.
To compensate for that I use a simple filter that is the reverse of that curve, +12db/oct and hence will flatten the curve again. This principle is known as ELF or Bagend and is used by manufacturers such as Velodyne.
Of course the amplifier power needed is substantial, due to the +12dB/oct boost. For 110dB at 100Hz amp power is 50-watt, then at 50Hz > 200-watt and at 25Hz > 800-watt and so on. Obviously for efficiency and power handling reasons I want a class-D amp to power the sub.
I've been reading up on class-D amp design in the past week(s) and designed the following schematic by borrowing ideas from around the web, here at diyaudio.com, in application notes and at the German Hifi-forum.de website. What do you think, am I on the right track here? With a power supply of +/-80-volts and a 2-ohm impedance I should be hitting my mark of about 800-watt RMS right? And please let me know if there's any glaring errors in the schematic.
Class-D sub amp schematic
http://hardwareanalysis.com/images/articles/large/11520.gif
Looking forward to the (many) replies.
Best regards,
Sander Sassen
http://www.hardwareanalysis.com