[Elecraft] K3 - How much supply voltage is too much?

[vr2xmc]

Very true indeed. The price for a decent regulated dc supply has dropped for the past years.

Sent from my  iPhone 4

Don Wilhelm <w3fpr at embarqmail.com> 於 2011年5月11日 上午11:44 寫道：

>  David,
> 
> I have many times commented negatively on the use of unregulated wall 
> warts for use with any radio because the no load (low load) voltage can 
> be substantially greater than the rated voltage (the specified voltage 
> is only at full load).  Many 12 volt wall warts will develop 17 volts or 
> more at no load.  Those power supplies intended for laptop computers may 
> do the job, but still, I shudder at using them unmodified, and that does 
> not speak to any potential spurious responses (some call them "birdies") 
> coming from the power supply.
> 
> Regulated wall warts are a different matter (birdies not considered) - 
> if they will provide the required current at 13.8 volts or so, then 
> there is no harm in using them, but the availability of  13.8 volt 
> regulated wall-warts is close to zero at the sources I normally use - it 
> seems all the available ones with sufficient current that I have located 
> are unregulated.
> 
> Use wall-warts and computer power supplies at your own peril.  For me, I 
> would not subject any radio to such a power source.  With the K3 in 
> particular, if one has spent upwards of $1.5k for the radio, then why 
> "go cheap" on the power source.  Spend a few extra dollars and obtain a 
> good 13.8 volt power supply - you will be more satisfied in the long run.
> 
> 73,
> Don W3FPR
> 
> On 5/10/2011 9:04 PM, David Gilbert wrote:
>> Didn't someone here not too long ago post some information on the
>> unreliable voltage regulation of many wallwart/laptop supplies?   Maybe
>> it wasn't this reflector.  In general, though, I believe the thread
>> mentioned that many of those supplies assume a load, and under no load
>> conditions the voltage often went up several volts.  The K3 has it's own
>> internal voltage regulators, but I'm not sure I'd want to subject them
>> to that sort of over voltage at turn on.
>> 
>> Dave   AB7E
>> 
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