Re: Tube regulator for removing ripple . . .

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mark Broker by way of Terry Fritz <teslalist-at-qwest-dot-net>" <mbroker-at-thegeekgroup-dot-org>

Pi filter - either LC or RC will work wonders.  The Pass Labs XA series 
audio amplifiers (the XA200 runs about $40kUSD!!) use multiple series RC 
filters for power supply ripple rejection.  I don't remember specific 
details, but the filters use thermistors.  Pi filters are supposed to work 
really well with class A loads (constant current draw), which sounds close 
to what you're doing.  A few quick and simple SPICE simulations would be a 
huge benefit, I think.

As someone else suggested, a capacitance multiplier would be good, too.
Although developed for an audio amp power supply, 
http://sound.westhost-dot-com/project15.htm is a good example of a capacitance 
multiplier, IMO.

Isn't this whole thread a little OT?

Regards,

Mark Broker
Chief Engineer, The Geek Group


On Tue, 01 Apr 2003 18:26:06 -0700, Tesla list <tesla-at-pupman-dot-com> wrote:

>Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><jimlux-at-earthlink-dot-net>
>
>Are you worried more about ripple or regulation?  I took a quick look at 
>an ARRL handbook (1990 edition) and they give a guideline of Lcrit = 
>Eout(Volts)/Iload (mA), so for 4000V and 1A, it would be 4H, a reasonable 
>size for an iron core choke.
>
>Reference data for Radio Engineers gives a design equation of
>ripple/output = 0.83/(LC) where L is in H and C in uF
>
>plugging in your number of 10V ripple (RMS or peak?)
>10/4000 = 0.83/(4*C) >>> C = .83/4*4000/10 >>> C = .83*4000/40 = 83 uF
>
>But.. make that a 20 H inductor, instead of 4H, and you're down to 16-17 uF...
>
>20H is certainly reasonable
>
>At 12:23 PM 4/1/2003 -0700, you wrote:
>>Original poster: "Mccauley, Daniel H by way of Terry Fritz 
>><teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
>>
>>
>>I'm currently building a 4kV DC supply for my VTTC which will be used for a
>>high-quality plasma speaker.  The only problem is removing the ripple on the
>>output of my full-wave rectifier to the point where the DC is very clean
>>(<10V ripple) Sure, this can be done with a boatload of capacitance but i'd
>>rather go about it with some type of floating linear-type tube regulator.
>>With 10-20uF capacitance I basically still have about 50-100V ripple
>>depending on load.  I used both solid state and tube regulators for doing
>>this same thing on a very large scale but never on a small scale such as
>>this.  Solid state would be nice but it is quite complex to get working
>>correctly and relatively expensive.  On the otherhand, maybe a simple tube
>>driven regulator my be a simple, inexpensive alternative.
>>
>>Any one have experience with this and know of some small power tubes that
>>can do this???
>>
>>Thanks
>>
>>The Captain
>
>
>