hi,
Irvy nice setup. 8mv dc very good.
CPX : add inductor at the output, as schema says at the bottom inductor its a must. 2 TL072 = 1 TL074 and use TL074. i just simulate it with LTspice and it works good. there is no noise at all. i already done tested IRF540N and IRF9540 with 4 ohm load +/- 45 vdc mosfet only warming up. Power supply need enough current to provide full power. at least 5amp with 8 ohm and 8 amp with 4 ohm.
regards.
Azmi.
Irvy nice setup. 8mv dc very good.
CPX : add inductor at the output, as schema says at the bottom inductor its a must. 2 TL072 = 1 TL074 and use TL074. i just simulate it with LTspice and it works good. there is no noise at all. i already done tested IRF540N and IRF9540 with 4 ohm load +/- 45 vdc mosfet only warming up. Power supply need enough current to provide full power. at least 5amp with 8 ohm and 8 amp with 4 ohm.
regards.
Azmi.
Thanks norazmi for answering me.
At first look i thought it is a class Ab amplifier since i do not understand the text under "Notas" except Sorenson Audio experiment .I looked that up and i am trying to exactly understand how it works.
In my opinion using tl072 as comparator is a very bad ideea since it is extremely slow(>20us propagation delay).Please post THD, IMD at minimum 4 amps,also switching residual .. i am very curios...
At first look i thought it is a class Ab amplifier since i do not understand the text under "Notas" except Sorenson Audio experiment .I looked that up and i am trying to exactly understand how it works.
In my opinion using tl072 as comparator is a very bad ideea since it is extremely slow(>20us propagation delay).Please post THD, IMD at minimum 4 amps,also switching residual .. i am very curios...
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It is apparently self-oscillating, hence self-adjusted with negative feedback loop. Being such a design a little delay error is ironed by feedback. Switching frequency is lowered with audio signal deviation from 0V, being the lowest near clipping.
A somewhat faster comparator could make regions near clipping somewhat nicer, but not by much.
I'd say this is a good design
A somewhat faster comparator could make regions near clipping somewhat nicer, but not by much.
I'd say this is a good design
Looks like a nice little amp, but is this really class D?!!? Looks like a MOSFET output class AB design from here. Regardless, building a working amp of any class this way is no mean feat. Congratulations on success, regardless. There are 800 page books out there regarding how to get a class AB amp working properly, and to do it successfully on the first try is really great!
here is my component value.my supply voltage is +/-43v DC.
the zeners are 5.1v for tl074 supply and 12v parallel with 1k resistor.
i use similar MJE340-350 instead of BD139-140 but there is no difference.
also i change irfp630-9530 with irfp540-9540 but nothing change.
However my simulation on proteus works right and initial PWM is stable and change right by input signal.
the zeners are 5.1v for tl074 supply and 12v parallel with 1k resistor.
i use similar MJE340-350 instead of BD139-140 but there is no difference.
also i change irfp630-9530 with irfp540-9540 but nothing change.
However my simulation on proteus works right and initial PWM is stable and change right by input signal.
Attachments
Hello
How do you provide a dead time in your schematic for the mosfet, so they would not switch on at same time ?
And where do you adjust that dead time in your schematic ?
Thank you
Bye
Gaetan
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Rezamir nice board.
please measure output offset, voltage at gate for each mosfet, many have build this amp, so far no problem about mosfet heating fast as long as u not reach +/- 50. Did u try with BD139 and BD140? i`m suspect there something error with ur component please double check it at your board. i`ve check 50% of your board seems to be ok.
btw what is the red trace for? on your board have blue trace and red trace, double sided board? As i can see transistor gate driver at right bd139 abd bd140 or maybe ur using mje340. mje 350, R20 ro Q6 , there is touching trace with R18? please check it while it shouldn't .
regards.
please measure output offset, voltage at gate for each mosfet, many have build this amp, so far no problem about mosfet heating fast as long as u not reach +/- 50. Did u try with BD139 and BD140? i`m suspect there something error with ur component please double check it at your board. i`ve check 50% of your board seems to be ok.
btw what is the red trace for? on your board have blue trace and red trace, double sided board? As i can see transistor gate driver at right bd139 abd bd140 or maybe ur using mje340. mje 350, R20 ro Q6 , there is touching trace with R18? please check it while it shouldn't .
regards.