NP recommended rectifier diode?

[calvert73]

What rectifier diode, (I think it was a fast recovery high power diode) did Nelso Pass admit to liking? I've searched but to no avail, I did make a note of it as I'd like to audition it but my note seems to have been tidied away by someone (again!).

RC

[Nelson Pass]

Try the STM BYW99W-200 listed by Digikey, and figure on
using the 2 diodes in it in parallel.

[GRollins]

Nelson,
I looked at the datasheet. I see that it is fast, but nothing about soft recovery. Do you have other information on that, or did I just miss it on the datasheet?
Yes, you could bypass it with caps to short the high frequency components, but...

Grey

[lineup]

Originally posted by Nelson Pass
Try the STM BYW99W-200 listed by Digikey, and figure on
using the 2 diodes in it in parallel.

calvert73.

Personally, I do not mind very much if my diodes
does soft, medium, hard or very hard recovering.

I have never cared about anything else, that my rectifier diodes
should in a good way rectify 50 Hertz AC to give DC output.


BYW99W-200. IT is a BIG DIODE. What I can see Max 15 Ampere.
Here is the datasheet: http://www.st.com/stonline/books/pdf/docs/2970.pdf

Packaged in SOT93, TOP3I or TO247
this device is intended for use in
- low voltage,
- high frequency inverters,
- free wheeling and
- polarity protection applications.

**lineup note:
high frequency,
they most probably mean a bit higher than 50-60 Hertz
... but I may be wrong here


Regards
lineup

[GRollins]

The ST part that Nelson referenced is specified for a 200A non-repetitive surge, but lacking something to limit the inrush, I can see why he says to run them in parallel.

Grey

[Nelson Pass]

We use inrush limiters.

[bobsinclar]

About the diodes recovery, I can remember Nelson writing he liked them as slow as possible, and even using bypass caps around the bridge to slower them better...that's what i always follow, I rellly don't look for the best hifi diodes, did anyone found a real advantage in using specific diodes for the rectifiers, I have to admit that I always use the cheap 30A monoblocks from the market...
Vince

[harryeng]

Closely related is the question whether to use one, or two rectifier bridges.

After long discussions some time ago in the SS thread Nelson gave a very clear answer on that;

Most customers want total silence from the amplifier, including
mechanical noise. If there is not complete matching between the secondary coils and only 1 rectifier bridge, any net DC imbalance between the current of the + supply and the - will tend to saturate the core of the transformer and create noise. This is seen for quite low current differences and can also show up with low frequency output. Using two bridges eliminates the problem.

In the eyes of a manufacturer, any other subtle differences pale in comparison to the cost of having to replace a transformer in the field due to mechanical noise.

Read the original here:

Greetings, Harry

[Nelson Pass]

Originally posted by bobsinclar
About the diodes recovery, I can remember Nelson writing he liked them as slow as possible, and even using bypass caps around the bridge to slower them better...that's what i always follow, I rellly don't look for the best hifi diodes, did anyone found a real advantage in using specific diodes for the rectifiers, I have to admit that I always use the cheap 30A monoblocks from the market

In 60 Hz rectification applications, I think the advantage offered
by fast diodes is mostly spurious noise reduction. They do
seem to sound better, but apart from that, they are necessary
to meet increasingly stringent EMI standards in various countries.

[Andersonix]

I remember NP recommending the use of a small capacitor and resistor in series across each diode in a rectifier bridge, rather than the use of fancy diodes. Does anyone remember the values of the cap and resistor, where I read this (I think Audio Amateur), and if this is still recommended?