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

[Bill]

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

-- 
IN GOD I TRUST (but, NOT a single politician)