First Class D sub amp

withnail · 25th January 2012, 03:36 PM

Wondering if anybody can point me to designs for a decent class D subwoofer amp?
This is my first audio project, although I'm well familiar with building electronics already. Budget is a concern, so I'd rather build it slowly, buying all the bits over time, than drop a lot on a kit.
I'm leaning towards quality over power, I don't really need it to deliver over 80 watts, in fact 50 or 40 would probably be fine. Obviously it would be mono and designed for the low frequencies of a sub. My passive sub is running from a pretty terrible loaned eltax amp at the moment and I want to build this amp to replace it.
Many thanks,
K.

nigelwright7557 · 25th January 2012, 09:55 PM

You can pick up a ready built pcb for less than you could build one yourself.
There are loads on ebay.

withnail · 26th January 2012, 12:50 PM

Thanks, but I'm not interested in a ready built one, that's why I'm on this site. Can anyone else help?

Kjeldsen · 26th January 2012, 01:15 PM

41Hz Audio - Main page has a lot of kits, that you have to solder yourself.

Osvaldo de Banfield · 26th January 2012, 01:38 PM

I´ve designed one of my own, and it have been working fine too the moment I put it out of service. The idea was a HCF4047 oscillating to 500KHz, divided internally by two, and out of fase from pin10 & 11.Two signals was integrated on an differential integrator around a 1/4 TS274. From here a pretty triangular wave, entering TS3702 push pull comparator, the other input receive audio amplified. From out TS3702, a HCF4049, a IRF9120/120 and then IRF9740/740. Double inductor and double capacitor (Four pole filter) and a small feedback loop from before filter, integrating to recover audio, and going to inverting audio input. All this with +12/-12V, except HCF´s working +6/-6V, all DC coupled. Simply but effective. I have the circuit in OrCAD SDTIII format if you like it.

withnail · 30th January 2012, 01:39 PM

Osvaldo: sounds excellent! The schematic would be great, if you'd be so kind

25th January 2012, 03:36 PM	#1
withnail diyAudio Member Join Date: Sep 2009	First Class D sub amp Wondering if anybody can point me to designs for a decent class D subwoofer amp? This is my first audio project, although I'm well familiar with building electronics already. Budget is a concern, so I'd rather build it slowly, buying all the bits over time, than drop a lot on a kit. I'm leaning towards quality over power, I don't really need it to deliver over 80 watts, in fact 50 or 40 would probably be fine. Obviously it would be mono and designed for the low frequencies of a sub. My passive sub is running from a pretty terrible loaned eltax amp at the moment and I want to build this amp to replace it. Many thanks, K.

25th January 2012, 09:55 PM	#2
nigelwright7557 diyAudio Member Join Date: Apr 2008 Location: Carlisle, England	You can pick up a ready built pcb for less than you could build one yourself. There are loads on ebay. __________________ http://www.murtonpikesystems.co.uk PCBCAD40 pcb design software.

26th January 2012, 01:38 PM	#5
Osvaldo de Banfield diyAudio Member Join Date: Dec 2011 Location: Barrio Garay,Almirante Brown, Buenos Aires, Argentina	I´ve designed one of my own, and it have been working fine too the moment I put it out of service. The idea was a HCF4047 oscillating to 500KHz, divided internally by two, and out of fase from pin10 & 11.Two signals was integrated on an differential integrator around a 1/4 TS274. From here a pretty triangular wave, entering TS3702 push pull comparator, the other input receive audio amplified. From out TS3702, a HCF4049, a IRF9120/120 and then IRF9740/740. Double inductor and double capacitor (Four pole filter) and a small feedback loop from before filter, integrating to recover audio, and going to inverting audio input. All this with +12/-12V, except HCF´s working +6/-6V, all DC coupled. Simply but effective. I have the circuit in OrCAD SDTIII format if you like it. __________________ A veces pongo un circo y me crecen los enanos... "Que se llama soledad", Joaquin Sabina, el capo.

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26th January 2012, 12:50 PM	#3
withnail diyAudio Member Join Date: Sep 2009	Thanks, but I'm not interested in a ready built one, that's why I'm on this site. Can anyone else help?

26th January 2012, 01:15 PM	#4
Kjeldsen diyAudio Member Join Date: Dec 2003 Location: Randers, Denmark	41Hz Audio - Main page has a lot of kits, that you have to solder yourself.

30th January 2012, 01:39 PM	#6
withnail diyAudio Member Join Date: Sep 2009	Osvaldo: sounds excellent! The schematic would be great, if you'd be so kind

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