Power supply for Amps

[polsol]

Sitting here in Kuwait i have a lot of time on my hands in the evenings so I thought that it would be a good idea to reinstate a long neglected hobby - Hi-Fi Audio.
As I cannot decide which of the DIY amps to build (JLH 10W, Hiraga 20W etc) I thought that it would be a good idea to try a few. The common item in all is, of course, the power supply which can be quite an expensive item.
So my thoughts have channeled along building a common power supply for one and all housed in a seperate enclosure. The PS would be composed of just the transformer, bridge rectifiers and caps with line regulation being done within the amplifier(s) themselves. Perhaps some form of output protection should be incorporated in this AC/DC converter box such as a regulated output (LM 338 type) when unplugging/plugging amps to it but would there be any problems associated with using two voltage regulators (power supply and amp) in series?
Is this feasible?
More to this forum topic, over the years I have seen references to transformers suitable for audio use. What, in particular makes one transformer more suitable for use in audio than another? Are there any recommended manufacturers?

Regards,
Tony