Semtech were known to be crazy about their diodes.
I remember Magnavox was using them in the GRC-106 SSB radio at 2400 volts.
The nly one ever gone was one cracked by over tightening the mounting
screws. I think that the diode chips inside the pack were way overkill but
it paid off.
Alex 4Z5KS
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Paul
Christensen
Sent: Sunday, September 15, 2013 6:16 PM
To: Amps
Subject: [Amps] Fwd: Rectifier equilization?
> 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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>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
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