low voltage PSU for Pedja Rogic's buffer

sith

Member
2003-11-20 6:25 pm
Split
Hello ppl, I'm planning to build Pedja Rogic's J-fet buffer like he did on his site or Nuuk on Decibel dungeon, still, I'm running to a bit of a problem, I want to use a separate PSU to feed it, I have +/-12V transformer, but I have problems with its realization - is it enough to make 'part 2' PSU from nuuk's site right after rectifier or I need to put some smoothing caps in front of it, although Pedja himself told me that for this circuit anything over 1000u is overkill...

Part 2 PSU in attachment :)
 

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Well that 12 volt traffo will give you between 16-17 volts assuming your mains supply does vary too much.

Pedja actually used an LM7815 reg on the same board as the buffer to keep it as compact as he could. However, the LM7815 would require around 18 volts in to give 15 out. You could try using an LM1084 that only has a 1 volt drop out, or go with a slightly larger tranformer. ;)
 

sith

Member
2003-11-20 6:25 pm
Split
Ye, I know it need some voltage swing (79xx), still, Pedja himself said that 'darlington' version is better than LM version... well nwm, I think I'll try LM version... Something like one in Nordic post over at SS forum (buffer for dummies), or Rod Elliots, project05, only with smaller snubber cap?