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Old 21st January 2006, 03:59 PM   #1
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Default no DC protection circuit ?

I built a pair of mono-blocks from UCD180. Was considering to build dc protection for them -- the question is, is it really necessary?
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Old 22nd January 2006, 06:00 AM   #2
MOER is offline MOER  United States
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Default DC

Yes it is
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Old 22nd January 2006, 07:08 AM   #3
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Only when the UcD fails....
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Old 22nd January 2006, 07:56 AM   #4
indoubt is offline indoubt  Netherlands
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Not with every failure of the UCD there is DC on the output. They seem to be pretty reliable anyway.
Not much failing UCD's either on this board or on the others that I visit. And yes, I'm searching cause I'm building a dual mono version and, for now, without DC protection.
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Old 22nd January 2006, 08:00 AM   #5
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Indoubt, are you looking for a protection design? (Of begrijp ik je verkeerd?)
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Old 22nd January 2006, 08:22 AM   #6
indoubt is offline indoubt  Netherlands
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Noop,

I think I do not need one but am investigating whether my perception is correct. Until now i've found remarkable little instances of DC on output related failures

Don't get me wrong, I think it is in general a good idea and the Hypex implementation in their HG supply looks great. I will use 140.000uF per channel (Nippon Chemicon, I think you use similar ?) and can therefore not use this supply (or I will have to throw away the cap's and that is a very expensive solution with double mono)
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Old 22nd January 2006, 08:31 AM   #7
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I'm using my UcD 400 without protection as well. For my UcD400 I use 40.000 uF per channel (Nichicon), why do you want to use so much capacitance?
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Old 22nd January 2006, 08:46 AM   #8
indoubt is offline indoubt  Netherlands
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Just because I can

I have them available from a never finalised Pass Labs Aleph X project, I will only use half as I have approx 560.000uF available. I will try 40.000 uf Slit foils per channel as well but most extreme amplifiers have ussually an extreme overload on capacity. I acknowledge that UCD's have less capacity requirement as conventional designs, at least in theory but they also seem to benefit from overdesigned PSU's. I will use UCD180AD with two 250Va schuro high end transformers.

With regard to DC protection, I have not found any sign from correct implemented UCD's with DC on the output, at least on the forums that I visit.
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Old 22nd January 2006, 08:59 AM   #9
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Haven't found any signs of DC either. I think it is important to use the stand-by switch for plop-free on/off switching.

What kind of rectifiers will you be using?
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Old 22nd January 2006, 09:16 AM   #10
indoubt is offline indoubt  Netherlands
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HFA 08 PB 60, these are 8A, 18 nanosec. They might be too light for the UCD400, I will use a softstart and probably heatsinks on the rectifiers. In principle the 8A should be sufficient but the UCD can draw 10 max. Withouth the softstart the giant caps could also draw more than 8A on startup so with softstart and heatsink think it's safe. If not I replace them by 25A types but they are slightly slower.

I think we are floating off topic, although the topic starter might benefit
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