PSU/Diode question

[iceman]

Hi !

I've got a couple of Diodes: MUR2020 & MUR3060
I wonder wich is the best to use in my PS.
Is it alway best to use the largest/biggest ??

MUR2020:
20A
200V
95ns Reverse recoverTime

MUR3060:
30A
200-600V
35 and 60ns Reverse recoverTime

If you want to know, my amp is about 25W /ch +-25V
My transformer is:

500VA
Primary 230V 50Hz
Secondary 2 x 18 V

 

[jan.didden]

One other thing to look at is the recovery characteristic. Soft recovery is normally better to avoid switching noise from the diodes. I would expect the 2020 to be soft recovery, but I don't have the data sheet. Other than that, I guess they are both suited.

Jan Didden

 

[Claude Abraham]

Iceman,

It depends on the ac voltage you are trying to rectify. The peak stress on the diode is 2.83 times the rms voltage of the ac waveform being rectified. If the ac voltage is 120 volts rms, then the peak stress is around 340 volts. Allowing for tolerances, a 400 volt diode should be used. A 200 volt diode should be used only if the rms value of the ac is 60 volts or less. I hope this helps.

 

[jan.didden]

....Claude, he said "2 x 18"...


Jan Didden

 

[iceman]

Diodes

Thank you for the answer.

I would rectifie (only 2 x18) so i use the 2020.

 

[Gasho]

MUR 3060 have shorter recovery time so it is little faster (letś say better) . You can use a Schottky power diodes , witch are much better for the sound character of audio electronics. Shottkyes are manufactured with max working voltages of 100V.

 

[Upupa Epops]

It's here again - sound of diodes. Strange world .

 

[Gasho]

It's here again - sound of diodes. Strange world .

Strange world with big influence.

 

[Upupa Epops]

If dioedes at PS have big influence on sound, something is wrong, fault isn't in these diodes.

 

[sivan_and]

Gasho wrote:

Shottkyes are manufactured with max working voltages of 100V.

WRONG !!
Have seen 600volt types ....

 

[sivan_and]

CSD20120
20A, 1200V Silicon Carbide Schottky Diode

 

[Gasho]

Gasho wrote: WRONG !!
Have seen 600volt types ....

Where? Can you tell me a model ??

And nothing i wrong , that type of diodes have no reversable voltage noise like avarage , and even fast recovery diodes , so there is no noise which can be interpolated ih PS and audio circuits.