05-06-2021, 08:05 AM
Tried a 100r across the choke and after the 2nd cap, so in series,no improvement. There's no room for the big 4700u cap. On another thread over on DIYAudio it was suggested my de-coupling might be an issue (de-coupling to 3 stages = positive FB) and also suggested to make the front end supply regulated. I re-jigged the de-coupling, still no improvement,haven't tried a regulated supply on the front end yet.
I can't for the life of me work out why the front end is going unstable & is it the front end starting bouncing first, the PSU first or both? Today I'm going to strip the amp back, pull stages, isolate the front end, get each block stable then go on from there. I've never had this problem before, lashed together prototypes have all worked fine. I have a sneaking suspicion that I've done something fundamentally wrong, like wiring to the wrong pins,left a ground wire off or something equally daft,but can't find anything at present. I'm also going to re-dress the ground bus and make sure the layout is correct.
Andy.
I can't for the life of me work out why the front end is going unstable & is it the front end starting bouncing first, the PSU first or both? Today I'm going to strip the amp back, pull stages, isolate the front end, get each block stable then go on from there. I've never had this problem before, lashed together prototypes have all worked fine. I have a sneaking suspicion that I've done something fundamentally wrong, like wiring to the wrong pins,left a ground wire off or something equally daft,but can't find anything at present. I'm also going to re-dress the ground bus and make sure the layout is correct.
Andy.
