My class D amp

Here is my modification. Any suggestion? The original one from Manojtm , can not run at high power rail . When connect +-80VDC and turn on the amp the power level is raise up to +-145VDC .That is not normal. So I have change the resistor at the emmiter of 2N5401 form 1K to 4.7K. The power level is steady at +-80VDC now. But I can not adjust the fsw by adjust resistor . If I decrease 1K to any lower value, the power level is raise up again.
How to solve this problem?
 

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i used bd243 and bd244 on irs4k5 without issues i used was +/-75vlts .

once i tried +/-90 vlts on irs 4k5 but it failed with 4ohm load (but it played loud for about 20 mins) and another channel without a load my outputs were irfp260n . i guess it was because of latching explained on ir design tip DT 99-7 also maybe my frequency :( :( but the gate drivers were o.k they did not get damaged in all the amp failures.
 
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Here is my modification. Any suggestion? The original one from Manojtm , can not run at high power rail . When connect +-80VDC and turn on the amp the power level is raise up to +-145VDC .That is not normal. So I have change the resistor at the emmiter of 2N5401 form 1K to 4.7K. The power level is steady at +-80VDC now. But I can not adjust the fsw by adjust resistor . If I decrease 1K to any lower value, the power level is raise up again.
How to solve this problem?

Hi opor,

For High supply design, level shifter should be properly aligned.

for +/-75v OR +/-85V supply change Resistor to 10K

check SMPS voltage without load
do not connect AMP without SP protect

Regards
MANOJ
 
Hi Manojtm,
Thank you . I have change resistor as your suggestion, so It can run at high supply rail. Even I decrease resistor to 560R to increase fsw. But there is new problem .Lower resistor than 820R ,there is DC out from amp that make hum. May be need dc offset adjustment circuit?