the irf240 does not have an emitter.
solution:- Take out all your FETs and select for equal Vgs at the operating current.
Am I wasting my time with unhelpful posts?
bad luck
that is why i said:
after his:
he did not take us seariously;me mistaking and you correcting...
that is why i said:
after his:
he did not take us seariously;me mistaking and you correcting...
guys i still have a problem with the 30mA bias current issue. in terms of voltage accross the source resistors (0.47ohms), is the voltage acccros them 14.1mV?
replace 470R trim-pot with 1k trim-pot and than adjust bias as you wish,or
http://www.diyaudio.com/forums/soli...mplifier-irfp240-irfp9240-67.html#post3228580
yesterday i did some mesurments at home with APEX HV23 at about 11,5Ohm resistor. it has given to me 45V/3,55A , 48V/4,05A and 51V/4,33A without clipping. at 53V there was 4,5A but clipping appeared. this all was at 1kHz frequency from signal-generator and lasted for about 15sec per measuring voltage/current. i did about ten this mesuraments so the amp was really taken to it´s maximum limits. it has got heated up but not so much more than it gets when it reaches it´s working temperature. it has only been left to find someone willing to share it´s loudspeakers with my amplifier to test it "live" and with music program instead tone-generator.
http://www.diyaudio.com/forums/soli...mplifier-irfp240-irfp9240-67.html#post3228580
yesterday i did some mesurments at home with APEX HV23 at about 11,5Ohm resistor. it has given to me 45V/3,55A , 48V/4,05A and 51V/4,33A without clipping. at 53V there was 4,5A but clipping appeared. this all was at 1kHz frequency from signal-generator and lasted for about 15sec per measuring voltage/current. i did about ten this mesuraments so the amp was really taken to it´s maximum limits. it has got heated up but not so much more than it gets when it reaches it´s working temperature. it has only been left to find someone willing to share it´s loudspeakers with my amplifier to test it "live" and with music program instead tone-generator.
Last edited:
so in other words, 30-50mA is the range to bias if the trimpot is 1k? and also the voltage i intend to use is 44-0-44 ac. i know power will be lower than the expected but its worth the try.
not in my case because i have +/-75V supply. i can adjust it to a 100mA per pair but i don't have heatsinks to cool it down,also it sounds the same with 15 and 100mA bias so why to exaggerate.
i don't know how much power you will get with +/-63V supply,but it is to be expected about 200W/8R and 300W/4R load. let us know when you measure! 🙂
i don't know how much power you will get with +/-63V supply,but it is to be expected about 200W/8R and 300W/4R load. let us know when you measure! 🙂
44250, i need the bias proceedure. things like initial values of resistances before and other information that i may need in this area.
It depends on how long it is switched on for and if the case has openings for airflow.
I used a similar setup in a pc case and after a couple of hours of high power I couldn't bear my hand on the pc case. So I fitted a couple of fans and it was fine after that.