I have no leads on a transformer but I've used switching power supplies from Amazon with good results. Two 12v supplies would give you +/-12V and 24V depending how you configure them. Various current ratings available to match your application. Just try to find ones that are floating negative (not grounded) to give you flexibility.
They won't fit in the original CDE box but should get the job done and probably for cheaper than the correct transformer if you can even find it.