Missed capacitor in 1kW schematic!
Must have 4u7 400V~ cap in series with power transformer.
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I have tested the amp without mosfets just by hooking up speaker at sg3525 outputs,sounds good but sg gets hot.
I am amazed by sound quality,very airy sound,not dark like lm1875.
I will experiment tomorrow with discrete gate driver,now im too tired.
Upon powerdown amp makes ugly noises after a second,then after 60 secs it hisses with slight sound of the music playing through it.These are very loud noises even though i had power limiting,i hope i can make them go away.
Btw i didnt use any inductor,sounds fine filterless for low power
I am amazed by sound quality,very airy sound,not dark like lm1875.
I will experiment tomorrow with discrete gate driver,now im too tired.
Upon powerdown amp makes ugly noises after a second,then after 60 secs it hisses with slight sound of the music playing through it.These are very loud noises even though i had power limiting,i hope i can make them go away.
Btw i didnt use any inductor,sounds fine filterless for low power
Simple amp. based on SG3525 PWM IC.
Frequency is fixed to 150kHz (fixed f is good choice) but you can modify it by changing RT/CT.
PWM is ~2-98% (which is very good).
IR2184 is HI/LO side gate driver.
Dead time provided by this IC.
Set the potentiometer on half.Turn amp ON.Set output voltage to 0V.
This amp works from first attempt
On PCB i have to use external 12V PSU for IC's
Max input voltage is +-80V.
With 4k7 adjust gain.
Output inductor is gapped core (can be used yelow toroids from AT/ATX PSU,they have internal gap.
In external 12V version you can regulate the output power only by voltage on fets.
12V is referenced to -V,not to GND!
On picture I used totem pole output instead of FET's and driver IC,but I tested wih IC and FET's too.
Hi Acca
and thank's for your project, it's very very interesting.
Never built a class D amp 'fully diy', but really this amp seems to be very easy indeed, to build and to understand too
Some older posts say this amp is not for hifi??
Only sub?
It seems it's due to low frequency switching - 150KHz - so can I, mean, increase it to 450KHz? By changing RT/CT?
And everything 'gonna be allright?
Is there a 'spot' frequency I should have to chose?
Or better I give up whith this project and go to buy UcD?
Thank you.
Carmelo
Hello iperv
Yes,very simple and very good.No sub,I use it on full range,with 150kHz osc. freq.
This means that all sounds up to 15kHz will have same audio quality as input (not same but very close).For me 150kHz is best freq.Easy to drive fet's,but sound good.Yes,you can easy change RT/CT.Go with smaller CT and larger RT.
You can increase to 450kHz but i don't recommend this. 300kHz is enough to reproduce all sounds up to 30kHz clearly.20Khz is max. frequency that people can hear.So 200kHz is best choice betwen gate drive and sound quality.Try first with 150kHz.If don't sound's good to you,increase freq.
My choice is to build it,not give up.You will learn many things.It is more efficient than UcD one.
Regards
Yes,very simple and very good.No sub,I use it on full range,with 150kHz osc. freq.
This means that all sounds up to 15kHz will have same audio quality as input (not same but very close).For me 150kHz is best freq.Easy to drive fet's,but sound good.Yes,you can easy change RT/CT.Go with smaller CT and larger RT.
You can increase to 450kHz but i don't recommend this. 300kHz is enough to reproduce all sounds up to 30kHz clearly.20Khz is max. frequency that people can hear.So 200kHz is best choice betwen gate drive and sound quality.Try first with 150kHz.If don't sound's good to you,increase freq.
My choice is to build it,not give up.You will learn many things.It is more efficient than UcD one.
Regards
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