jleaman said:
Give the guy who sold you the kit a call and explain what you're up against. He'll probably be more than happy to assist you.
jleaman said:
carpenter said:
Hi All,
Apparently I mixed up IRFP240 and IRFP9240 here. However if Jase got too many IRFP240, there will be someone that received only IRFP9240.
Jase...Did I mess up 1 or both sets? I will send the IRFP9240's that you miss. The least I can do after all the trouble you had.
Marcel.
Hi,
I have finished building a pair of F4 and am very happy with its sound. Just to share what my friend advised me while I was building the amps. Before soldering the Power FETs, it is good to do these checks:
1. Power the pcb with +/- 22V and check current of positive side about 11-12mA (LED 2.2mA + K170/J74 7-8mA, others 1mA). If the current is too high, your Jfet, TL431, diodes or zener may be reversed.
2. Check the two 10ohm source resistor of K170 and J74, it should be 7-8mA, voltage drop 70 to 80 mV.
3. Check the 10ohm resistor and C1/C2 point to see if the voltage is close to ground 0V.
4. Adjust P1 to full clockwise, the voltage between 240 gate and 9240 gate should be >8.5V, adjust P1 to full anticlockwise, the voltage between 240 gate and 9240 gate should not more than 7.5V. Keep the P1 full anticlockwise position which means that the bias is minimum.
5. At this stage, there is no need to adjust P2 for DC offset at output as there is no power mosfet and bias and the offset has to be adjusted with all that.
6. Then the pcb is ready to be mount on the heat sink and solder all the power mosfet. Make sure that 240 and 9240 is at correct position.
Best Regards
I have finished building a pair of F4 and am very happy with its sound. Just to share what my friend advised me while I was building the amps. Before soldering the Power FETs, it is good to do these checks:
1. Power the pcb with +/- 22V and check current of positive side about 11-12mA (LED 2.2mA + K170/J74 7-8mA, others 1mA). If the current is too high, your Jfet, TL431, diodes or zener may be reversed.
2. Check the two 10ohm source resistor of K170 and J74, it should be 7-8mA, voltage drop 70 to 80 mV.
3. Check the 10ohm resistor and C1/C2 point to see if the voltage is close to ground 0V.
4. Adjust P1 to full clockwise, the voltage between 240 gate and 9240 gate should be >8.5V, adjust P1 to full anticlockwise, the voltage between 240 gate and 9240 gate should not more than 7.5V. Keep the P1 full anticlockwise position which means that the bias is minimum.
5. At this stage, there is no need to adjust P2 for DC offset at output as there is no power mosfet and bias and the offset has to be adjusted with all that.
6. Then the pcb is ready to be mount on the heat sink and solder all the power mosfet. Make sure that 240 and 9240 is at correct position.
Best Regards
Hi,
Just a remark....adjusting P1 depends on your circuit design..it maybe the other way round, i.e. clockwise will reduce current, instead of increasing current.
Best Regards.
Just a remark....adjusting P1 depends on your circuit design..it maybe the other way round, i.e. clockwise will reduce current, instead of increasing current.
Best Regards.
Member
Joined 2002
carpenter said:
I agree, every one makes mistakes, its just a simple one and i am VERY happy to see that you can help.
Scotts batch of fet's is perfect it has 6 IRFP9240's and 6 IRFP240's, it was just a coincidence i guess, 🙂 if you could send just one batch 6 of each that would be perfect 🙂
Thanks.
Jase
Member
Joined 2002
Its alive and noooo smoke 😛 WOOT!! thanks for every ones help 😛 i replaced the other side with the correct fets, i have about 0.08mvs on the dc output and 100mv across the resistors, i have HUGE heat sinks what should i set the bias at ? any guesses ? 300 - 400 ?
Jase
Jase
Member
Joined 2002
carpenter said:
Well i have some pretty big heat sinks 😛 about 10" x 12 😛 they are pretty slick, im sure i can get up to 600mv 😛 im not looking for a space saving heater LOL..
Jase
... or perhaps a blast furnace?
I'm hoping to crank mine up a bit; at least the midbass units. The treble horns are 110db 1W1M and don't require more than a couple watts.😀
Good luck and do keep us posted. If I see a bright light in the sky out your way, I'll know that you went too far. 😉
I'm hoping to crank mine up a bit; at least the midbass units. The treble horns are 110db 1W1M and don't require more than a couple watts.😀
Good luck and do keep us posted. If I see a bright light in the sky out your way, I'll know that you went too far. 😉
Member
Joined 2002
carpenter said:
well my maximum Bias is 340mv. It wont go any further 😛 ( the pot starts licking meaning its at the end )
Jase
Member
Joined 2002
Member
Joined 2002
Dougie085 said:Hey Jase,
Just wanted to remind you cd's are a dying format. 😉 😀
What's taking their place? iPods?
Well was mostly just a joke. But something of the sorts. Solidstate is going to take place of everything eventually. Movies, Music even video games will move to solid state media. I'll only get digital media if its in HQ though which is very high quality MP3 rips (not your normal crap you get off itunes) or a lossless codec.
But my comment above was for fun and games 😉
But my comment above was for fun and games 😉