Hello, I am very excited since I have build a working P68 and I thought I'd share back with the community that I have learned so much from. Well it is complete as far as the circutry goes, it produces sound, very deep bass might I add. Still working on the enclosure since I can't find anything that this will fit into. Well I was on a limited budget so I didn't buy the PCB but instead I designed my own, and I needed more hours for my senior project too, which this took about 3, plus 9 for the fabrication. Maybe for my senior project in college I will design the amp myself but for now, I used Rod's design.
Well I still have some problems that I have to solve, the 3.3 Kohm resistors R10 and R11 get really hot, even after I changed them to 1 Watt, started out with 1/2 Watt but they got even hotter, so I decided to change them.
The second problem is when I plug the amplifier in the outlet, it makes a THUMP sound when the volume is turned up, is this in any way damaging the output transistors or anything at all, the speaker maybe?
The last problem for now is, when I have the fan working, because Q7 and Q8 heat up the heat sink to a relatively warm temperature, have yet to measure it, there is a hum that is thrown back into the amp, I am pretty sure it is at 60 Hz, and I know it comes from the fan because when I hold it, it has an auto shut off circuit inside and it turns off for a couple of seconds, during which the hum disapears. The fan is 24 VDC, and I didn't use a regulator, only a rectifier and a capacitor which is 2200uF, I just need to know how I can get rid of that hum? Other than that it's pretty noiseless, when it's idiling.
Well here are the pictures enjoy and don't hesitate to ask for more:
Picture of the Subwoofer Controler PCB by Rod
In the construction phase
The Amp's driving circuitry
The bottom side of the driving circuitry
The complete setup bottom of output stage
The complete setup top of the heat sink
Thanks, Petar.
Well I still have some problems that I have to solve, the 3.3 Kohm resistors R10 and R11 get really hot, even after I changed them to 1 Watt, started out with 1/2 Watt but they got even hotter, so I decided to change them.
The second problem is when I plug the amplifier in the outlet, it makes a THUMP sound when the volume is turned up, is this in any way damaging the output transistors or anything at all, the speaker maybe?
The last problem for now is, when I have the fan working, because Q7 and Q8 heat up the heat sink to a relatively warm temperature, have yet to measure it, there is a hum that is thrown back into the amp, I am pretty sure it is at 60 Hz, and I know it comes from the fan because when I hold it, it has an auto shut off circuit inside and it turns off for a couple of seconds, during which the hum disapears. The fan is 24 VDC, and I didn't use a regulator, only a rectifier and a capacitor which is 2200uF, I just need to know how I can get rid of that hum? Other than that it's pretty noiseless, when it's idiling.
Well here are the pictures enjoy and don't hesitate to ask for more:
Picture of the Subwoofer Controler PCB by Rod
In the construction phase
The Amp's driving circuitry
The bottom side of the driving circuitry
The complete setup bottom of output stage
The complete setup top of the heat sink
Thanks, Petar.
PetarLD said:
No, I wasn't saying you're stupid, I intended that most of us make many big, beautiful things, but also little stupid things. And the devil is in the details... I was referring to a little wiring mistake that most of us sometimes do.
Sorry if I didn't express me well, English is not my native language.
Cheers
Ok, guys sorry about the pictures not showing up anymore, I had that domain for free but it was only a trial period, I'll try to get them hosted somewhere else, in the meanwhile please feel free to ask me any questions.
Update: I have put this amplifier in an old computer case and I am using the computer ps for powering the cooling fan and it's working pretty good, I'll post pictures of the final product as soon as I go home for christmas break.
Update: I have put this amplifier in an old computer case and I am using the computer ps for powering the cooling fan and it's working pretty good, I'll post pictures of the final product as soon as I go home for christmas break.
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