Ultra fast diodes

[akis]

Hi, I have noticed some here use fast diodes for mains rectification, but those 20-50ns diodes are made for high frequencies, and in addition they have higher voltage drop (1.8+ Volts) compared to the standard recovery diodes (1.1 Volts). Could someone please tell me what is the benefit for using them ?

[pacificblue]

Some people believe that faster switching would mean diode ringing was reduced, which should be good for the audible performance. A few people even claim to hear an improvement. That claim is sufficient for others to use Schottky diodes without double-checking. Well, why not? Others claim to hear a difference between different fuses in the distribution box through their amplifier and people pay a lot of money for silver-plated fuse sockets, gold-plated fuses and an electrician to replace the old ones.

Not that it costs a lot to buy some Schottkys and form your own opinion.

[Lumba Ogir]

akis,
keep a check on BYW29. (Vf=0.8V).

[AndrewT]

Originally posted by akis
they have higher voltage drop (1.8+ Volts) compared to the standard recovery diodes (1.1 Volts).

at what currents?
What is a normal current for your use?
What will be the Vf for a suitable rectifier for your chosen current?

A clue:
Vf will not be >=1.1V

[akis]

Originally posted by Lumba Ogir
akis,
keep a check on BYW29. (Vf=0.8V).

It appears this is 200V only.

Originally posted by AndrewT
at what currents?
What is a normal current for your use?
What will be the Vf for a suitable rectifier for your chosen current?

A clue:
Vf will not be >=1.1V

In comparison to similar standard diodes and similar currents, the fast ones have greater voltage drops. I did not do an extensive study, just checked a few.

[Lumba Ogir]

akis,
MUR1560 600V at the cost of speed.

[nikwal]

I use byr29f usually..