The pins on the outputs (lateral mosfets) are Gate, Drain and Source. I assume you mean Gate, what are the other two pins voltages? Does this 0V show on the pair of outputs for that channel (either N or P). If you get same on the matching output, I would lean towards something bad before the outputs in the circuit. If not, then you could be right and the mosfet is shorted. I have generally seen them shorted and you would get rail voltage on the outputs, but not always.
Easiest way to find the fault is to compare voltages on the working channel. Anything that doesn't match - post here and we can help guide you to the problem.
Easiest way to find the fault is to compare voltages on the working channel. Anything that doesn't match - post here and we can help guide you to the problem.
I have a transformer of dual 40V so I've ordered 15000uf 63V capacitors. But the mains are 230V. It seems I will have nearly 60V after BR.
Do I need the ones with higher voltage? Or should I order another troidal transformer with 35V(38V seems to be better, but can't find any)?
Any helpful advice will be appreciated.
Do I need the ones with higher voltage? Or should I order another troidal transformer with 35V(38V seems to be better, but can't find any)?
Any helpful advice will be appreciated.
Couple thoughts- higher voltage caps would provide more safety margin, but if your 230 is stable, then you should be fine with 63V caps, only you can decide if that margin is enough.
If you are asking about safety for the amplifier, Ii currently run mine with +\-65V rails and have had no issues.
Its DIY so you get to decide your comfort level and build to it.
If you are asking about safety for the amplifier, Ii currently run mine with +\-65V rails and have had no issues.
Its DIY so you get to decide your comfort level and build to it.
Hello ksjung88,
Assuming you live in Europe and here the power supplier normally has a tolerance of +/-10% of the voltage drop they supply, so 230Vac can give a maximum of 253Vac or a minimum of 207Vac.
Then the min/max tolerance for the secondary on your transformer will be approx. +/-10% (disregarding losses etc on the way) and gives the secondary max approx. 44Vac and min approx. 36Vac. This gives approx. rail voltage of +/- 50.9-62.2Vdc depending on how your mains voltage into the house is from your power supplier.
Then there is how capacitors cope with the voltage, there is always a certain tolerance on them too, and yes they tolerate to a certain extent a certain amount of "overvoltage".
But the next thing you should look at is what your outputs can withstand, I have bad experience with V4H and 55Vdc - resulted in full fire in one output stage.
So if you can change the transformer voltage, I think 35Vacx2 would be a good choice.
Assuming you live in Europe and here the power supplier normally has a tolerance of +/-10% of the voltage drop they supply, so 230Vac can give a maximum of 253Vac or a minimum of 207Vac.
Then the min/max tolerance for the secondary on your transformer will be approx. +/-10% (disregarding losses etc on the way) and gives the secondary max approx. 44Vac and min approx. 36Vac. This gives approx. rail voltage of +/- 50.9-62.2Vdc depending on how your mains voltage into the house is from your power supplier.
Then there is how capacitors cope with the voltage, there is always a certain tolerance on them too, and yes they tolerate to a certain extent a certain amount of "overvoltage".
But the next thing you should look at is what your outputs can withstand, I have bad experience with V4H and 55Vdc - resulted in full fire in one output stage.
So if you can change the transformer voltage, I think 35Vacx2 would be a good choice.
Hello Torvbakkane. I live in Korea. With 230VAC, secondary output is 42V. So Rail voltage is about 60v. I heard if there is some load, it will drop by some voltage. That's why I posted the above quetion. Shaan said 35V will be OK. Seems I need more time to agonize on it. Thank you so much for advice. And Merry Christmas. bullittstang and you!
It seems like OP stage oscillating due to capacitive loading. If you haven't already, use 10uH/10ohm network at output.
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Hi Shaan. Long since last message. The vendor from which I purchsase the 40V transformer has no 35V one until coming Feb. So I am looking for some local makers. Maybe more expensive than factory-made one, but will be better. Or move on with 60V. What do you recommed for total uf with each PSU. I have 60k(15K*4) with each PSU. And, very happy to hear your next project keeps going well. I think I will join it after completing this board at hand.(Even though One more sets are awaiting). Thansk for taking time to comment.
