That is a very interesting build, but a bit scrambled to see what's happening. Can I suggest you back out and better organize the wiring. You may discover the problem during that process. There is always the rule of thumb - separate signal from power as best you can.
Can you add a top view?
Can you add a top view?
If the hum is new, Andrew has pointed out a likely source - damaged filter capacitors.
There's also the possibility that your grounding scheme is at fault.
There's also the possibility that your grounding scheme is at fault.
I reversed after the caps, they should have seen nothing but a lot of current going besides them?
I can adjust currents and voltages across the resistors just like before, so there should be all ok with those? If they were much off their nominal value, it wouldn't hum because of that I think?
I can adjust currents and voltages across the resistors just like before, so there should be all ok with those? If they were much off their nominal value, it wouldn't hum because of that I think?
Last edited:
Yes, both channels.
In the yellow rectangle you see the center cables of the transformer connected to ground, obscuring the rectifier below ...
You also see 2 resistors leading to the power LED
In the yellow rectangle you see the center cables of the transformer connected to ground, obscuring the rectifier below ...
You also see 2 resistors leading to the power LED
Good suggestion is to take out all wiring in power supply and to signal boards. Start again. Easy to make wiring mistake and tough to find when you test everything at the end. Try to route wires in a bundle, use non-metalic bag ties or tie wraps when completed.
It doesn't take much to blow up a high current amp, especially with point to point wiring.
Good luck.
It doesn't take much to blow up a high current amp, especially with point to point wiring.
Good luck.
Wish I could see something but I can't. It's been my experience that while focused on fixing one area the physical activity may force a break (cold solder joint etc.) or short elsewhere. If it were my project I'd pull back to the individual sections and add them back in one at a time.
Good Luck!
Edit: Ya - What they said 🙂 I do admire your point to point approach
Good Luck!
Edit: Ya - What they said 🙂 I do admire your point to point approach
Last edited:
I guess it might be possible
a curcuit might cause small amount of hum if not well adjusted so that part of a curcuit is working outside its optimal
have experienced this with other curcuit a few times
but that would be speculation here
and I'm really a no-nothing when it comes to this 😀