Well....
Most power supplies out there are CRC filtered units....a cap input unit...
Less common is the LC or choke input...
Now, to make it real simple, if you stick a choke in front of the first cap in a cap input power supply, it does become a choke input supply...BUT, your voltages will be all screwed up...why? Well that first cap charges up with the rectified, but unsmoothed, voltage from your rectifier(s) and it has the effect of hopping up the voltage a bit...it's late and I can't remember the figure now....
But, you change and stick a choke in the input and you don't get that voltage boost of that first cap and the voltage output, no matter what quantity of capacitance you have in the following RC or LC stage, will not be as high as the cap input filter...the action of the inductor prevents this...
So, this throws off all the voltages and operating points of the tubes in the unit...
And, yeah, you can replace a power supply resistor with a choke, and since it is a cap input filter, you shouldn't lose much (if any) of the dynamics...what yeo was talking about in that article was choke input vs. cap input....just make sure that it has sufficient current capacity for your unit...
Building a choke input power supply is something that takes a bit of doing...we don't make use of a lot of the knowledge of these power supplies from the pre-WWII area today...plus, there aren't the manufacturers around today that supply chokes for different needs...like swinging chokes...a choke usually used in the input position of a LC supply to help stabilize voltages....i.e., a swinging choke has more inductace at low current flow rates and less at high current flows....there are also ways to "tune" subsequent chokes with a capacitor across them to make them more effective at smoothing ripple...that lack of swinging chokes and more info on implementing them may be one of the things that leads to Yeo's assessment that choke supplies seem slower....
But, he really says it all when he says: Okay, my approach to good sounding, not too expensive power supply circuitry is this. I like lots of chokes and very little capacitance. When you don't have lots of capacitance, you really need lots of chokes. Unfortunately, this makes your amp really heavy. Chokes are cheaper than quality capacitors.[/b]
Anyhow, these are just the late night rambling thoughts of someone who has forgotten more than they know!
Good luck and have fun...
