DC Servo MOSFET Amplifier

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need correction.....
 

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Q1 and Q2 are BC556, and connect input gnd to psu gnd...

Hi Mile,

I already fixed the problem when I use IRFP240/9240 to instead IRF640/9640,
the sound is good and very low distortion but the bass not really enough even I used 100uf for C6, the sound still thin if compare with AX14, but the high to middle range on F100 is better.

The DC rail voltage is +/-44 now.

Any suggestion to improve the sound more thickness.

Thanks a lot.

Ben
 
if anyone has some time...

This old pcb with 5 pairs of outputs and protect can be redesign for FB400

i have done a pcb for FB400,i haven´t checked it yet so if anyone has time and wants i would be gratefull to him,specially if he would point me for possible mistakes done. input is done so there can be used all electrolit capacitors with belonging resistors (C1,C2,R1,R2) or without them using only one big capacitor like wima 4,7uF or similar. here are the pdf,jpg and lay (SPRINT) files:
 

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i have done a pcb for FB400,i haven´t checked it yet so if anyone has time and wants i would be gratefull to him,specially if he would point me for possible mistakes done. input is done so there can be used all electrolit capacitors with belonging resistors (C1,C2,R1,R2) or without them using only one big capacitor like wima 4,7uF or similar. here are the pdf,jpg and lay (SPRINT) files:

Nice work,
Regards
 
Nice work, but I suggest speaker protect on pcb instead big caps.
Regards

thanks for suggestion Mile,wich protection do you suggest,and on what resistor should it "sense",the 2r2 sors or 0,32r emiter resistor?

when i get some more time i will try to do it. i have a plan to draw another one like this,just with two pairs of bipolar transistors because i do not need all 400W of power,and i guess that even with two pairs of bipolars this amplifier would easy reach about 150-200W of power at 4R load.

one more thing- i have read that bias sgould be around 200mA (measured at source resistor) but what voltage supply should be used with FB400 with all five output pairs,and what voltage would be suggested for two pairs of bipolar transistors at the output?


sorry for a lot of questions,but i would really like to hear that someone has built this amplifier and his impressions about it. that is why i did pcb for it,and will do a few more...
 
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