It is difficult to accept but I will need to completely rebuild the power amps and control circuitry. That is what this stage of the build is all about, finding out what is wrong and how things can be improved.
The right-hand power amp is drawing a lot more current than it should be and although I have been through and found a fault the problem is still there. The difficulty I have is that it is incredibly difficult to fault find the power amps because of the way they are constructed; air-wired. Without the rigid form that PCBs give, it is very easy to lose where one is in the circuit. Plus the lack of rigidity means that shorts between components are all too easy. I had intended to lock the components in place by using hot-melt glue when the circuit has proved itself to work. However, it won’t work without the hot-melt glue because of shorting.
There are implications for this problem too. If it takes me lots of time to construct, fault find and correct, the cost of construction will rise rapidly as my labour time increases. So I have to find a way of construction that is quick and accurate plus easy to fault find and correct.
I have decided that what I need is to use a substrate that will show me where components should be and hold them exactly in place, much like a PCB would do. What I will do is layout the components, to scale, on the computer, complete with hole positions and fix that to some flat sheet, probably something like Tufnol. This should solve all the above problems and also speed up construction as I can drill a few sheets at a time, drilling through say 10 at once.