[Elecraft] K3 - what power supply are you using?

[Joe Subich, W4TV]

This has been covered several times ...

 > Are the 20 amp supplies enough power for the K3?

They are marginal - I have seen 22A or slightly more with some
loads on some bands.  Given that the current metering is somewhat
an average, the instantaneous peaks will be higher.  25A is a
realistic minimum and I'm more comfortable with 30A.

 > Are switchers any good or is their track record poor for life
 > and noise?

I'm not a fan of switchers for both electrical and acoustic noise.
Switchers also seem to be less tolerant of peak current demands.

 > Should I consider anything other than Astron?

Not in my opinion.  I have two RS35A - one for each K3 - set to 15V to
improve IMD at full power levels.

If you use a battery supply, limit maximum power to 75 watts as the
voltage drop at peak current - particularly when the batteries are not
full charged - will increase IMD significantly.  IMD is marginal at
13.8V and increases significantly at lower (11.5-13V) levels.

In addition, a single battery supply for all equipment significantly
increases the potential for problems.

73,

    ... Joe, W4TV


On 10/11/2012 7:09 AM, Bill wrote:
> I am about to replace my 35 year old Astron 35 amp supply. The choices
> are switchers or analog and 20 or 35 amp. The supply will ONLY be used
> for the K3. Everything else in the shack is on a different supply.
> Questions:
>
> Are the 20 amp supplies enough power for the K3?
> Are switchers any good or is their track record poor for life and noise?
> Should I consider anything other than Astron?
>
> Thanks,
>
> Bill W2BLC
>