How to reduse voltage from PSU??
Hi!
I am building an Aleph 5 clone, and used PCB-KK pcb's.
Anyone with a god tip how too reduse 42,6V to 33-35V.
(500VA toroids)
I have 6X10000uF (each canal), and I have 42,6V before load is conected. When I connected an 8,4ohm load I mesure 37,1V.
That is a little to high for an Aleph 5 clone.
I planed to 0,235R in series with the + and - just after the bridge, is this a good solution to get the voltage down?
What is the negative with this solution?
😕
O.B Lerum
Hi!
I am building an Aleph 5 clone, and used PCB-KK pcb's.
Anyone with a god tip how too reduse 42,6V to 33-35V.
(500VA toroids)
I have 6X10000uF (each canal), and I have 42,6V before load is conected. When I connected an 8,4ohm load I mesure 37,1V.
That is a little to high for an Aleph 5 clone.
I planed to 0,235R in series with the + and - just after the bridge, is this a good solution to get the voltage down?
What is the negative with this solution?
😕
O.B Lerum
Hi,
I'll start this one off, but i'll need alot of correcting as i'm still a bit of a newbie.
Firstly if you put a resistor in series after the bridge and before your filter caps, you have to remember that you are creating an RC filter low pass filter as well. with a 0.235r and a 10000uF filter cap alone you have a low pass filter operating at a frequency of 68hz, this is not good.
Secondly, the power supply should have as close to 0 resistance as possible, to improve the damping characteristics of the PSU, your large array 10000uF in parallel really help to keep overall impedance of the PSU down, it would be a shame to add 0.235ohms there.
You could either change you design to a fully regulated one, or use more wasteful bridges, and/or diodes to reduce the voltage, although this is a wasteful act.
Alex
I'll start this one off, but i'll need alot of correcting as i'm still a bit of a newbie.
Firstly if you put a resistor in series after the bridge and before your filter caps, you have to remember that you are creating an RC filter low pass filter as well. with a 0.235r and a 10000uF filter cap alone you have a low pass filter operating at a frequency of 68hz, this is not good.
Secondly, the power supply should have as close to 0 resistance as possible, to improve the damping characteristics of the PSU, your large array 10000uF in parallel really help to keep overall impedance of the PSU down, it would be a shame to add 0.235ohms there.
You could either change you design to a fully regulated one, or use more wasteful bridges, and/or diodes to reduce the voltage, although this is a wasteful act.
Alex
Hi,
Search on CRC filters, common in valve amplifier supplies.
Adding R immediately after the bridge will not work
well as it limits the charging current to the capacitors.
also take a look at this :
http://sound.westhost.com/project15.htm
A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers
🙂/sreten.
Search on CRC filters, common in valve amplifier supplies.
Adding R immediately after the bridge will not work
well as it limits the charging current to the capacitors.
also take a look at this :
http://sound.westhost.com/project15.htm
A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers
🙂/sreten.
I think this issue has already been addressed by others and commented by Mr. Pass. Since it's a class A design, current consumption is fairly stable, which gives alternatives.
Try searching for keywords on this subject, and posts by Nelson Pass.
Jennice
Try searching for keywords on this subject, and posts by Nelson Pass.
Jennice
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