[ARC5] 28VDC Regulator

[J Mcvey]

 I don't know how much current those radios draw, but there is going to be a lot of heat dissipation with a 17 volt drop across the pass transitor!  You might consider a bucking circuit and put it in a box with some RF I/O shielding.

If you want to stay analog,  just use a something like 2n3055 or two for pass and dirve them with a single transistor reference amp.  You don't need nth degree regulation...



    On Sunday, July 1, 2018, 6:43:53 PM EDT, Robert Eleazer <releazer at earthlink.net> wrote:  
 
  Today I found a Toshiba AM/FM stereo receiver someone hadthrown out.  It was dead but yielded a  nice big heavy transformerthat has a number of outputs, including one with 64VCT.  I still would liketo build a dedicated 27.5VDC power supply that could run my ARC-114 andARC-116.  They run fine on my variable bench power supply.  Ihave found the LM317 and related series to be inadequate due to its inputvoltage limitation. I looked at the  LM338 specs and it does not refer toan input voltage limitation, although max output is 32VDC and output versusinput cannot be greater than 40VDC. That 64VCT transformer will give meabout 45VDC cap filtered input to the regulator. So, do y'all think the LM338K will do the job? Needless tosay I would rather stay linear and not use a switcher. Thanks WayneWB5WSV      

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