> As a data point, ETO used a quad set of Semtech SCH5000 "SlimPac" diodes in
> the Alpha 70 and 77 series. These are rated at 5KV but only 500mA of
> continuous current.
>
> It may have been a marginal design, but I don't believe there's been a really
> poor history of diode failure in these amps over the years.
>
> Paul, W9AC
>
> Sent from my iPhone5
>
> On Sep 14, 2013, at 9:44 PM, Jim W7RY <w7ry@centurytel.net> wrote:
>
>> I completely agree that 6A10s are real overkill.
>>
>> 73
>> Jim W7RY
>>
>>
>> On 9/14/2013 12:14 PM, Manfred Mornhinweg wrote:
>>> Bill,
>>>
>>>> FYI for next time, 6A10 diodes have become preferred by many for high power
>>>> use because of their 6 amp continuous and 400 amp surge ratings and
>>>> moderate
>>>> cost.
>>>
>>> I don't mean to say anything against 6A10 diodes, they sure work fine. But
>>> they are HUGE overkill. Even if the filter capacitors had zero equivalent
>>> series resistance, and the power outlet where the amp is connected had zero
>>> impedance, and there were absolutely no inrush limiting system used, and
>>> the power were switched on in just the worst possible moment (peak of
>>> waveform), just the resistance of the HV transformer will limit the current
>>> to roughly 20 to 30A, or maybe 40A if the transformer is really beefy. And
>>> such a condition of course doesn't happen in real life - specially the line
>>> from which the amplifier is powered does have some resistance and also some
>>> inductance. In practical use, in a normal home, it would be really rare to
>>> see more than 15A inrush current.
>>>
>>> 1N5408 diode has a 200A surge rating, which is still big overkill. The
>>> humble 1N4007 with its 30A surge rating would be about the right part to
>>> choose for a cost-conscious builder! It's also comfortable with the average
>>> current. Rated at 1 ampere average, a bridge rectifier using strings of
>>> 1N4007 diodes is good for 2 amperes. That gives enough headroom for a legal
>>> limit amp.
>>>
>>> Feel free, of course, to use big diodes, if it gives you peace of mind. But
>>> it shouldn't be technically necessary.
>>>
>>>
>>> Jim,
>>>
>>>> ## Both my 1N5408 and 6A10 diodes have identical lead diameters.
>>>
>>> So do mine.
>>>
>>>> Both are I think, .050
>>>
>>> Yes.
>>>
>>> Manfred
>>>
>>> ========================
>>> Visit my hobby homepage!
>>> http://ludens.cl
>>> ========================
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>>
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