Elpac used to make a linear, regulated 12V PSU (6W max, 500 mA DC output current) with good regulation and ripple: WM060-1950-760
Elpac no longer lists this on their webpage of currently offered PSU's.
BTW, its 24V brother, the WM080-1950-760 IS still listed on their webpage.
What IS available from Elpac in a 12V linear, regulated PSU is the:
WM144-1950-760 (14.4W max, 1.2A DC output)
Its regulation and ripple are not as tight as those of the lower capacity, unavailable one above.
Here's are a few links to distributor offerings of this PSU: Neward and Allied
ELPAC POWER SYSTEMS | WM144-1950-760 | Power Supplies | Power Products | Newark.com
https://www.alliedelec.com/Search/Pr...WM144-1950-760
I googled "Elpac WM060-1950-760" looking for a distributor that may still have one in stock, but only Allied came up in those, and Allied no longer lists this PSU on their website or in their catalog. So, it looks like that well has dried up.
What are you trying to power and what is its current draw?