Electronics > Projects, Designs, and Technical Stuff
Improvements for old linear power supply - should be fairly straightforward!
David Hess:
The resistors can serve other functions besides redistributing the power dissipation away from the regulators:
1. The additional RC section helps remove reverse recovery noise from the rectifiers.
2. The series resistors act as fusible links for safety in the event of a short.
schmitt trigger:
If you would consider a better, but more invasive improvement: I would add a separate, lower voltage transformer and rectifier for the purpose of feeding the +/-5 volt regulators instead of feeding them from the +/-15 volt rails.
tophat:
--- Quote ---You may safely lower the resistance value and simultaneously increase a capacitance a bit.
For example you may change 4R7-2200uF to 3R3 or 2R7 and to 3300uF or 4700 uF.
You may safely increase C12 and C17 up to 6800 uF (up to C6, C9 value).
My way to lower PCB temperature is to put larger power resistors (if there is enough place), for example I'll use 2x10R 2W resistors in parallel instead of one 4R7 2W (but the amount of heat is the same in such way).
--- End quote ---
This is closest to my current line of thinking.
--- Quote --- The series resistors act as fusible links for safety in the event of a short.
--- End quote ---
I think the unit would catch fire if the circuit protection was based solely around these resistors... not sure what advantage there would be considering them a possible fuse, I can only think of disadvantages...
--- Quote ---If you would consider a better, but more invasive improvement: I would add a separate, lower voltage transformer and rectifier for the purpose of feeding the +/-5 volt regulators instead of feeding them from the +/-15 volt rails.
--- End quote ---
There are already two separate transformers, one for the analogue preamp stages and the other for the digital stages. Three would be an improvement yet again but I don't think there is enough space in the chassis, and if there were enough space I would be concerned about the added heat - something which is already on the edge.
Thanks very much for everyone's inputs. It is good to bounce ideas around :)
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