Hi. Just finished the ACA mini build and biased it last night. Tested it with Schiit SYS and cd player and sounded good. Today, I moved some things around to make room for all the stuff, and one of the speaker wires came loose. Reconnected and now, when I fire the thing up, loud feedback/buzz/noise from one side (red). Any ideas what I should check appreciated.
Thanks! It’s on one side only. The red one. When I unplug it it stops. Plug it back in, starts again. I tried just the green side. Sound and no hum/buzz. On the red one, reseated all cables, tried different speaker cables. When it powers on, hum/buzz/feedback starts slowly and builds. Touching the positive speaker terminal with the speaker wire or the red rca plug starts the buzz/hum/sounds like grounding issue. Disconnect either of those and the noise goes away. Just don’t know what I should check.
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Thanks. More info: when switching it stayed with the red side. I turned my cd player off, noise dissipates. Turn CD player on, starts up again. So, tried different source, phono preamp into the SYS. Noise almost gone, but of static but not dead quiet. Turned phono and amp off, and slowly there was noise coming from speakers, sounded like garbled music (not what I was playing). Very perplexing. Is it possible I’m getting feedback from somewhere? This is in my bedroom and nothing else plugged in near it.
I’d guess a loose solder joint or broken input connector. Reflow all of those connections. Look for wayward solder bridges.
Check RCA jacks are properly isolated from chassis, sometimes there is movement of the plastic insulating washers and the rca jack makes contact
Have changed power supplies on anything?
Have changed power supplies on anything?
Thanks. Will check. Nope, I just built it and this is first times powering it up.
From earlier post—-
I turned my cd player off, noise dissipates. Turn CD player on, starts up again. So, tried different source, phono preamp into the SYS. Noise almost gone, but of static but not dead quiet. Turned phono and amp off, and slowly there was noise coming from speakers, sounded like garbled music (not what I was playing).
Send pictures.
If you live close to a broadcast station something could be acting like a diode detector. Cold solder joints are famous for it.
If you live close to a broadcast station something could be acting like a diode detector. Cold solder joints are famous for it.
If only the center pin of the RCA is making contact, it will cause a loud buzz. Confirm that the sleeve of the RCA on the opposing end of the RCA cable (while connected to the ACA mini) is making a good connection with the negative speaker terminal. Your speakers buzz so we know that is a good reference point.
Thanks all. I’m an amateur and it looks like my soldering skills need work. Noticed some spots need fixing. Will do that today and report back.
Noticed a bunch of bad soldier joints. Think I fixed most. Problem still persists. I’ll send pictures. I did notice on a few of my resistors soldier leaked thru to the other side. I tried to clean these up as best as possible. Hum/buzz still exists. Any other things to try look at - appreciated.
Thanks Mike. Can you elaborate here—confirm that the rca (going from the ACA) is making contact with the negative speaker terminal?
There are many cold solder joints.
It appears that the solder pad is broken where the arrow is pointing.
You are going to need to: at a minimum. Take your soldering iron and reheat every joint on the board until the solder flows onto the part being soldered and the circuit board.
