Hi masood,
1) i used laser printer to print pcb circuit on HP or Novajet photoglossy paper 130GSM (very important as simple A4 sheet will not work).
2) then i used toner transfer method(search it on net).
3) Do not remove the paper until you are sure that toner has transferred to copper surface.
4) remove the paper & correct the toner traces by scratching with pointed thing or connect the traces using nailpolish.
5) let it dry for 10 mins. then dip in ferric chloride solution & keep stirring the solution.
this method does not work well with very fine traces(0.2mm or less).
i have made pcb of nmos500 with this method.
can you help with my queries?
i am also beginner & only mechanical engg.
1) i used laser printer to print pcb circuit on HP or Novajet photoglossy paper 130GSM (very important as simple A4 sheet will not work).
2) then i used toner transfer method(search it on net).
3) Do not remove the paper until you are sure that toner has transferred to copper surface.
4) remove the paper & correct the toner traces by scratching with pointed thing or connect the traces using nailpolish.
5) let it dry for 10 mins. then dip in ferric chloride solution & keep stirring the solution.
this method does not work well with very fine traces(0.2mm or less).
i have made pcb of nmos500 with this method.
can you help with my queries?
i am also beginner & only mechanical engg.
dear sanju,
thanks for giving your advice.i have made many pcb but clarity is not by this method.i want to expose and develop image by chemical .plz. u also search this method because in india there is not available pre sensitized clad board and developer spray chemical can.
i am only an ordinary sales man in shop.it is my top hobby thank u.yours masood
thanks for giving your advice.i have made many pcb but clarity is not by this method.i want to expose and develop image by chemical .plz. u also search this method because in india there is not available pre sensitized clad board and developer spray chemical can.
i am only an ordinary sales man in shop.it is my top hobby thank u.yours masood
Hi masood,
i have only build 2 nmos 500.one was perfect,the other one well, it sounded harsh. after sometime of playing ,one power resistor of o/p mosfet cracked while the first channel was doing good.i think the second channel was oscillating.i abandoned the project as there were other ways to get more power (i only need sub woofer amp not HI - FI).
I am building bridged apex550 with 54 volt dc of rail voltage .It will give me over 700 watts of power @ 4 ohm.There are advantages
1) 63 volt caps can be used(cheap)
2) 1/4 watt resistor can be used
3) probability of both channels dying at the same time is less
4) i think i can use bd139/bd140 in place of mje15030/15031(my dj amp has the same topology (it has got 32 o/p transistor
)
i will start the project of av800 after apex550,but i have no access to oscilloscope .
i will hard wire the o/p mosfets (which results in oscillation)
do you have deep knowledge of mosfet(like input capacitance etc.)?
is irfp460 & irfp240 lateral mosfets or vertical mosfet.
what is the price of the mosfets that you mentioned.
here the price of one irfp 460 is Rs. 60
2n3773 is Rs. 52
mje15031 is Rs 55
i have only build 2 nmos 500.one was perfect,the other one well, it sounded harsh. after sometime of playing ,one power resistor of o/p mosfet cracked while the first channel was doing good.i think the second channel was oscillating.i abandoned the project as there were other ways to get more power (i only need sub woofer amp not HI - FI).
I am building bridged apex550 with 54 volt dc of rail voltage .It will give me over 700 watts of power @ 4 ohm.There are advantages
1) 63 volt caps can be used(cheap)
2) 1/4 watt resistor can be used
3) probability of both channels dying at the same time is less
4) i think i can use bd139/bd140 in place of mje15030/15031(my dj amp has the same topology (it has got 32 o/p transistor
)i will start the project of av800 after apex550,but i have no access to oscilloscope
.i will hard wire the o/p mosfets (which results in oscillation)
do you have deep knowledge of mosfet(like input capacitance etc.)?
is irfp460 & irfp240 lateral mosfets or vertical mosfet.
what is the price of the mosfets that you mentioned.
here the price of one irfp 460 is Rs. 60
2n3773 is Rs. 52
mje15031 is Rs 55
Quasi's can be prone to oscillation.
My design did to start with but some fiddling with feedback capacitors sorted it out. The lower driver transistor needed a 100pf from base to collector.
The VAS feedback capacitor also needed upping to 100pf too.
After that it worked fine for many years.
Are your bd139/140 rated at >108Vceo? What about adding say 10% to cover for spiking on the supply rail?
Lateral mosFETs are described as such in the datasheet.
Vertical MosFETs are usually described as switching in the datasheets.
How would this circuit compare to a commercial amplifier such as Audiolab 8200A? I have the 8200A and wonder if I can improve on the sound quality with this design.
