I'm building this amp
The artice says the max output current is 20 ma
Here's the psu
I'd like to use a 5U4GB retifier because I have a bunch laying around and a 235-0-235 @270ma transformer. I put some values into PSU designer but I'm not shure about the rectifiers limits? How should I change the capacitors values so that it's within the rectifiers range?
An externally hosted image should be here but it was not working when we last tested it.
The artice says the max output current is 20 ma
Here's the psu
An externally hosted image should be here but it was not working when we last tested it.
I'd like to use a 5U4GB retifier because I have a bunch laying around and a 235-0-235 @270ma transformer. I put some values into PSU designer but I'm not shure about the rectifiers limits? How should I change the capacitors values so that it's within the rectifiers range?
Sure... 150 uF is fine.
MerlinB,
As the the input cap gets larger, the diode conducts for a shorter duration of time (conduction angle). Equal energy, in less time, means more current. Instead of "ripple current"... think of it has "peak charging current". This current kills the diode. Inrush is not a problem because the tube diode wakes up slowly.
MerlinB,
As the the input cap gets larger, the diode conducts for a shorter duration of time (conduction angle). Equal energy, in less time, means more current. Instead of "ripple current"... think of it has "peak charging current". This current kills the diode. Inrush is not a problem because the tube diode wakes up slowly.
Hi phn,
Cheap chokes are what happens when your kid throws the cordless phone into the swimming pool or knocks the Weber (popular American outdoor cooking grill) over loaded with ribeyes (expensive and tender beef steak).
Chokes find their advantage ($$) when the wattage levels go up.
Cheap chokes are what happens when your kid throws the cordless phone into the swimming pool or knocks the Weber (popular American outdoor cooking grill) over loaded with ribeyes (expensive and tender beef steak).
Chokes find their advantage ($$) when the wattage levels go up.
poobah said:Sure... 150 uF is fine.
I don't normally disagree with the furry one (!), but I still recommend running these values through PSUD before hanging 40uF plus another resistor-isolated 300uF off that rectifier. 220 ohms feels low.
Not really I just don't want to kill the rectifier. I just need 250V at 20mapoobah said:sbelyo,
Are you designing to meet a certain spec for PSU ripple? The bigger is better mentality is all good... this IS about fanatics after all. But, there is always a cost or problem when overkill is at work.
Yes,
But also you should be looking at ripple voltage as well. Look at the min and max voltages of your final cap. The difference between these two is the ripple voltage and that could be audible. Larger caps will reduce this voltage; buit also increase currents... it is a comprimise you must balance.
Try experimenting with a larger resistor & smaller caps as rdf suggested. If your supply comes out at 240 Volts, that will make very little difference in the sound, if any. A ten fold reduction in ripple could make a real difference.
Do you have a specification for the desired ripple voltage>? What caps were in the original design?
But also you should be looking at ripple voltage as well. Look at the min and max voltages of your final cap. The difference between these two is the ripple voltage and that could be audible. Larger caps will reduce this voltage; buit also increase currents... it is a comprimise you must balance.
Try experimenting with a larger resistor & smaller caps as rdf suggested. If your supply comes out at 240 Volts, that will make very little difference in the sound, if any. A ten fold reduction in ripple could make a real difference.
Do you have a specification for the desired ripple voltage>? What caps were in the original design?
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