Grounds concept/direction/advice

I have built a number of perfboard circuits, mostly chip amps. I usually built each module as a monoblock, ala chip amp kits; each with its own star ground. They work perfect individually, however in stereo or bridged mode, the sound one channel dominates the other channel.

I believe the problem is the location of common ground because i don't have issues with circuits i build as stereo.

So, in an aid to designing better perfboard grounds, (where ground planes are not possible) Should I:

1) Create 2 star grounds, one for signal and one for power

2) Pull out the common grounds from each channel into a common ground at psu ground

3) Connect both grounds at every possible opportune, ie signal, power and speaker ends.

Any advice/debate would be lovely