SFX Class D subwoofer amplifier modification

[sagarverma]

I have been sifting thru this forum for a simple Class D amplifierwhen i stumbled upon the fact that this
Class D amplifier has been constructed by SFX for his sub.
what i want is to make it a dual supply version,is it possible?

 

[Tekko]

Why not keep it as is ?

 

[sagarverma]

actually i want to use that amp in my car.i have a smps in the car giving output as + - V. I will be replacing TDA729x amps in the car bec they are big(mostly bec of heatsink).
so i want the amp to be able to hook up directly to the smps without unnecessarily straining it
moreover,isnt a dual supply version better than the single supply one?
can anyone suggest the requisite changes?

 

[sagarverma]

at least..can anyone check the schematic given at the website and tell wether its correct or not?

 

[Genomerics]

It's not Buy One Get One Free.

What would you do?

DNA

 

[sagarverma]

i want to make a class d amp,dual supply one.
this one is too simple and so attracts me.
the other one is complex but promises good quality.
i will finish this one and come to that pretty soon(provided this one is correct)
can anyone check it for errors?

 

[sagarverma]

isn't there even a single person who can check this scheme for errors??

 

[Tekko]

You could check this:

Its my contribution on making the TB a split supply version, but it may not work, the pwm works, thats tested in simulator, but the power part i dunno.

 

[sagarverma]

hi Tekko,
thank u for your reply.
BTW,is the single supply schematic correct....if i go with that only then is that safe....?
power part....hw can that be corrected(tested) in your version?

 

[Tekko]

I have simulated the pulsewith modulator, tho the triangle was more of a sine it seemed to work.

But i´d still rdcommend you to build the thunderball after the original schem from the author. If you wanna build a split supply amp, try Titanchen´s circuit.

 

[sagarverma]

so single supply version schematic is ok.then i will make it bec it looks so easy!
Titanchen´s circuit<<<<<<<will give it a try when i find it.
i think that the circuit of thunderball is gerived from crown audio ckt which is single supply and uses bca topology.

 

[Tekko]

Look for the thread "post filter feedback question"

 

[ajazz]

I think there is a mistake in the original schematic, if u compare BCA. Either the audio or Triangle has to go into common inv or non-inv input of comparator, and the other signal has to go inverted into the other end.
You can easily convert this circuit into +- supply with level shifting plus you get an advantage of providing global feedback for good sound quality.
Best of luck,
ajazz

 

[sagarverma]

How to do that?
can u convert it?

Sagar

 

[ajazz]

Power the Quad Opamp and the comparator with a dual supply like +-5V. Level shift the output of the comparator with a pnp tansistor like MPSA92 to the neg rail of +-HV with a 560ohms on the emitter to +5 and a 1Kohms on the collector to -HV. Feed the output from the collector to IR2113 or other mos drive. Take a voltage divider feedback from the output(after coil) and feed in the non-inv input of first opamp and Wow ! ! ur amp is ready.

If u want I shall draw the schematics by today evening & shall post it. But I would prefer u try it first and let us know.

best of luck
ajazz

 

[sagarverma]

Hi Ajazz,
If i had known what to do i had not been here askin for help
plz do the schematic.

Sagar

 

[ajazz]

I will try my best taking some time out tomorrow

 

[sagarverma]

hey!
did u find time?

Sagar

 

[Tekko]

You may be interested in a circuit i have spent the last days mocking up:

I am currently listening to it, the osc freq is 480KHz so its is pretty well suited for fullrange, it actually sound pretty good.

 

[sagarverma]

hi tekko
thanks for the schematic.
what is the Power output of this circuit?
moreover mosfets>>IRF540 or ^640(the pic reso is not good)
regarding the inductor whats the core,dimensions,wire thickness turns etc?
the circuit looks too simple to be true .

Sagar