Linear Regulator in series for symmetrical PS?

[dougduck]

What are the problems with using a linear regulator like the LM317 in series to have a symmetrical PS? (isolated windings)

The most common is to use the negative regulator, but i want to manufacture some boards, and this makes it easier to make a single positive design and be able to use it in series if i need a symmetrical source.
Can anyone explain to me if there would be any problem with load balancing or any other problem?

[Andy Chee]

The problem with isolated windings is that the device being powered may not like it.

Is this supposed to be a generic laboratory supply?  Or do you have a specific device being powered?

[Kleinstein]

It is OK to have 2 fully seprate positive regulators (including isolated transformer windings) and than series connect the 2 regulated voltages. This is how most dual lab supplies are build.
It however really need them to be seprate and one can not use something like a split transformer winding.

What is problematic is having the 2 regualtors from the same raw DC in series. In this can one would have to make sure that the load current is higher at the lower part (which looks like the negative side to the outside).

The normal way is to use a LM317 and LM337  for the negative side or corresponding fixed voltage ones.