Good choice, a somewhat less benign version of the 1N4004 I would say, same voltages and currents (over the whole range of diodes).
UF4002 Fairchild Semiconductor Rectifiers
This are the diodes i use ..
UF 4004 - Ultraschnelle Gleichrichterdiode, DO41, 400V, 1A - 1N.. - UF.. - AA.. Dioden bei reichelt elektronik
Why not build something and look with a scope what happens ?
UF 4004 - Ultraschnelle Gleichrichterdiode, DO41, 400V, 1A - 1N.. - UF.. - AA.. Dioden bei reichelt elektronik
Why not build something and look with a scope what happens ?
Two things, my information is (was not) WEB based, and secondly I did change my insight (opinion) and changed the resistor value to 100 Ohms. The question is would you (and [all] others) agree to these values?
Regards,
Frans.
P.s.
[All] I am now wondering (if ever) all could agree to one idea
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Yes it is, and still it will do. But I think the actual part (in first selection) will be something like the UF4004 (as proposed by Joachim). And having a PCB that accepts 'single' diode devices will give us plenty of room to experiment with other devices.
Concerning PSU i would say no !
Some have religious believe in a certain topology, other use certain components ( mostly big and clumsy ) , other claim that an LM317, 337 combo is just fine.
I can only repeat that the Paradise has excellent PSU rejection to begin with. Then Frans made a really good regulator that is already proven in the lab to be very low noise and then we have the pre-regulator external so everybody can try what he thinks is best. Hesener even made provision that the on board shunts can be disabled.
I have measured inside PSUs and especially around the bridges there is more going on then some will think. We really have to build this, make it work and then look if we can fine tune.
Some have religious believe in a certain topology, other use certain components ( mostly big and clumsy ) , other claim that an LM317, 337 combo is just fine.
I can only repeat that the Paradise has excellent PSU rejection to begin with. Then Frans made a really good regulator that is already proven in the lab to be very low noise and then we have the pre-regulator external so everybody can try what he thinks is best. Hesener even made provision that the on board shunts can be disabled.
I have measured inside PSUs and especially around the bridges there is more going on then some will think. We really have to build this, make it work and then look if we can fine tune.
Wait a minute, now if I am wrong it will be all my fault
Maybe I was not clear about this, but that was my intention, and that is why I added the p.s.
[All] I am now wondering (if ever) all could agree to one idea
I see the snubber that way :
R x C create a time constant. If you rase R, C has to go down in value or you get a rather low time constant that may not be effective any more at the high frequency switching spike of the diode. Making R high reduces the damping of the snubber though so a compromise has to be found. I would say the lowest R that works.
I usually use no snubber at all and it works with the UF4004. A C alone without resistor will not work well i think.
R x C create a time constant. If you rase R, C has to go down in value or you get a rather low time constant that may not be effective any more at the high frequency switching spike of the diode. Making R high reduces the damping of the snubber though so a compromise has to be found. I would say the lowest R that works.
I usually use no snubber at all and it works with the UF4004. A C alone without resistor will not work well i think.
Most information that I have relates the value of R to the amount of energy that needs to be dissipated (Motorola, National and Rifa). In a way that leaves the C as the variable/value to calculate, but I cannot find information on how to calculate the value of R, other than the formulas found in the Hagener document.
I do agree with Joachim about the need to experiment and measure. Using 100 Ohm and 100 nF seems like a good starting point. It is in accordance with values that are found in National and Rifa papers and (the value for R at the least) agrees with Hagener's paper.
The National information that I have suggests that using a C only will suffice; it goes on to say that the power (of the energy to dissipate) will then be dissipated in the internal resistance of the capacitor, diode and the wiring. (this is for small (like ours) power supplies).
The literal text is “Capacitor shunt on the rectifier diode. Transient power is thus dissipated in the circuit series resistance”.
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Funny, nobody has found out so far whats really going on. I see this as an opportunity to find out.
Anyway, this is a minor problem. I am just listening to a phono stage with UF4004 without snubber and the sound is great. Extremely low noise. I can hear the type of vinyl in the lead groove.
Anyway, this is a minor problem. I am just listening to a phono stage with UF4004 without snubber and the sound is great. Extremely low noise. I can hear the type of vinyl in the lead groove.
