I have a bunch of ON-Semi Schottky Power Diodes (MBR40250)that I was going to replace the 15A 400V diode bridge with.
The DC Rails are + & -70VDC (so the secondaries are 50VAC).
Has anyone tried these and what were the effects in sound quality if any.
My amp is a Rotel RB991 rated at 200/300 WPC RMS (at 8/4 ohms respectively).
Can you see any issues other than I have to heatsink them and the DC Rail Voltage will increase by 1 to 1.5 VDC as result of the 0.6VDC drop versus the Diode Bridge that drops up to 2 VDC.
My PS Caps are rated for 80VDC as well.
These diodes have the 250VDC rating so I am thinking I am OK.
Any comments or experience would be appreciated.
Thanks,
The DC Rails are + & -70VDC (so the secondaries are 50VAC).
Has anyone tried these and what were the effects in sound quality if any.
My amp is a Rotel RB991 rated at 200/300 WPC RMS (at 8/4 ohms respectively).
Can you see any issues other than I have to heatsink them and the DC Rail Voltage will increase by 1 to 1.5 VDC as result of the 0.6VDC drop versus the Diode Bridge that drops up to 2 VDC.
My PS Caps are rated for 80VDC as well.
These diodes have the 250VDC rating so I am thinking I am OK.
Any comments or experience would be appreciated.
Thanks,
Schottkys are fast...very fast. While they make less noise, they do so at higher frequencies... more energy in the higher spectra. This may or may not slip through your filtering.
I guess I'm not too keen on them for line rectification because they are fragile; The voltage spec on a schottky is a line you don't pass... not for a picosecond.
Breakdown of silicon diode is an avalanche process. The spike tolerance is based on thermal issues. Different deal in a schottky I believe.
I guess I'm old school here... if you can hear your diodes, you have other issues.
I guess I'm not too keen on them for line rectification because they are fragile; The voltage spec on a schottky is a line you don't pass... not for a picosecond.
Breakdown of silicon diode is an avalanche process. The spike tolerance is based on thermal issues. Different deal in a schottky I believe.
I guess I'm old school here... if you can hear your diodes, you have other issues.
Dtm,
the rating seems to be fine, just make sure the heatsinking is adequate and that you wire your brigde correctly. You should be in good shape.
Booyeah Poobah!
are you kidding around or are you trying to be controversially old fashion here?
I don't think there's anything new or wrong here. Diode replacement has been one of the standard mods done by thousands of people for the past 15 years (at least) with great results. I am one of these thousands. I just recently completed an update/restoration on an accuphase e-202 and the results have been tremendous. I made the updates in stages to try to isolate the most beneficial and gain a better understanding of works and what doesn't. I must say the diode replacement produced very audible changes.
the rating seems to be fine, just make sure the heatsinking is adequate and that you wire your brigde correctly. You should be in good shape.
Booyeah Poobah!
are you kidding around or are you trying to be controversially old fashion here?
I don't think there's anything new or wrong here. Diode replacement has been one of the standard mods done by thousands of people for the past 15 years (at least) with great results. I am one of these thousands. I just recently completed an update/restoration on an accuphase e-202 and the results have been tremendous. I made the updates in stages to try to isolate the most beneficial and gain a better understanding of works and what doesn't. I must say the diode replacement produced very audible changes.
and these changes were???
The fact that thousands do it means little... look at cables for example. Swapping diodes is popular because, like cables, it is safe.
I am not saying that swapping to schottkys won't change the sound. I am saying that unless you have the equipment to quantify the before and after noise in your power supply supply, and its spectral distribution; you will be relying on your ears for proof. Your ears will likely prefer the "upgrade"... for better or worse.
The point remains... if you can hear your diodes; you have filtering problems.
The fact that thousands do it means little... look at cables for example. Swapping diodes is popular because, like cables, it is safe.
I am not saying that swapping to schottkys won't change the sound. I am saying that unless you have the equipment to quantify the before and after noise in your power supply supply, and its spectral distribution; you will be relying on your ears for proof. Your ears will likely prefer the "upgrade"... for better or worse.
The point remains... if you can hear your diodes; you have filtering problems.
I generally agree with poobah : shottcky diode are most fast than others for redressment. they 're too less strong, and by construction (tiny silicium layer) heat so much.
For the sound, I think that not change anything if the filtering is good ( higher frequencies must be appear with this sort of diode but i don't know).
For the sound, I think that not change anything if the filtering is good ( higher frequencies must be appear with this sort of diode but i don't know).
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