Re: Replacement power transistors hfe.
I've never found that! For starters, Vbe is temperature dependent, so as the thing gets hotter, Vbe falls and you'd think it was passing less current.
For a bench supply, the output current is often metered and a fairly accurate current-limit control added, so current sensing needs to be a low-error method. The bench supplies I have seen, have all used resistors.
Radiomuseum shows the 2N2147 as being TO3, but other sites TO111. Can't comment here! But if the output transistors are low hfe, then yes the driver will work harder, as David RW says
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