single rail linear negative supply

[zamproject]

Hi

I'm currently designing (mostly cloning) and old audio -tool- that use a single -24V supply
Probably artefact from early Ge design, even if it's a Si transistor design.

The question is about regulation IC and design choice.
At this stage I think I should have the room on a single eurocard (100x160mm) to fit the rectifier/regulation too.

Is there any technical reason to use let say 7924 -normally wired- over a 7824 with output referenced to GND and GND pin as -24 output ?
I see the benefit of 78xx/79xx combo in a symetrical supply with centre taped main trafo, but here ?

Cheers
Zam

 

[JohnRoberts]

It is generally good practice to use ICs the way they were intended to be used.

JR

 

[zamproject]

Yes...but there is nothing in the 78xx series that state where the main ref should be fitted !?!
Design notes and basic circuit application schemo offer negative rail wiring.

I'm not expert how IC are designed, but I see the 79xx series utility for simplicity where sym rail with single rectifier and center taped trafo is used ?

I see linear PSU design with dual (or more) secondary, using only 78xx

Cheers
Zam

 

[Matador]

What you propose works fine, provided you have an isolated winding or a single supply. Just."ground" the output and take the supply from the ADJ pin (or resistor if adjustable).