[ARC5] Chopper PS feeding a Linear Regulator?

[Bob kb8tq]

Hi

Also be aware that if you go to a faster switcher (that will handle the variable load) the LM317’s PSRR 
ratings aren’t going to be up to the task. 

So no, it’s not trivial. 

Bob

> On Jun 15, 2019, at 12:26 PM, Scott Robinson <s at balrogs.org> wrote:
> 
> Beware of a  problem in such supplies, if the chopper runs at line frequency. Many HP lab supplies had an SCR pre-regulator followed by a linear. These supplies don't work well with SSB or CW transmitters, as the SCR pre-regulator isn't fast enough for the variable load.
> 
> FWIW,
> 
> Scott Robinson
> 
> On 6/15/19 9:04 AM, Robert Eleazer wrote:
>> Any of y'all ever tried taking a chopper type power supply and feeing it into a linear regulator, like an LM317?
>>  
>> I found an HP power supply with a 32VDC 2.5A output and that would be perfect voltage for feeding a 28VDC power supply I built to power an ARC-114 or ARC-116.
>>  
>> I subsequently built a whole new power supply using a discarded stereo amp transformer and some very hefty discarded caps and pass transistors and that works fine.  But another way to power my first attempt would be welcome.
>>  
>> Thanks!
>> 
>> Wayne
>> WB5WSV 
>> 
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