Thanks again, I have one more question.

One amp has 12 output devices per monobloc and is rated 400 amps into 4 ohms ( something like 10k microfarad filtering through each monobloc). It is driving the speakers with excellent result.

Another amp has say 6 output devices for stereo and is also rated 400 amps into 4 ohms. It is not, howerver doing the job.

If you bridge the second amp, you still only have 6 output devices but you now have ~800 amps into 4 ohms. Would this make a difference?