Hey guys, I hope this is the right place to post this. I have 3 Mackie SRM450 (I believe they're all V2) and currently one of them is working. I'm a gigging musician (just starting out, usually once a week or so). I'd like to get at least one of them up & running in case the 3rd one fails in the middle of a set. My dad and I are looking at fixing it ourselves - he's been working on electronics his entire life so we're going to give it a shot. The speaker we're looking at repairing first turns on and functions pretty well up to a certain volume. It gets a little distorted at higher volumes and makes a weird chirping noise after it gets too high. Heres a video of what I'm looking at. Any feedback would be greatly appreciated.
YouTube
YouTube
Mackie SRM 450 Issue
I believe it's a 450V - my dad and I are looking at trying a DIY repair. He's more experienced in electronics so if anyone has any suggestions on a diagnosis to get a leg up we'd be greatly appreciative.
Works fine at lower volumes - when pushing it higher performing volumes it tends to distort a bit and then make this weird chirping sound.
Here's an example
YouTube
I believe it's a 450V - my dad and I are looking at trying a DIY repair. He's more experienced in electronics so if anyone has any suggestions on a diagnosis to get a leg up we'd be greatly appreciative.
Works fine at lower volumes - when pushing it higher performing volumes it tends to distort a bit and then make this weird chirping sound.
Here's an example
YouTube
I think you have answered your problem within your last sentence.. "any feedback would be greatly appreciated" ..you are too close to your speaker when playing, so you get "feedback" happening (search "Audio feedback") notice how it stops when you clamp the strings with your hand, get a bit of distance between you and the speaker and see if it stops.
cheers.
cheers.
monitor B+ lines and check supply bypass caps that's the sound of verging on instability/oscillation that i'm hearing in the you tube vid.
the other suspect is intermittent ground or cracked solder joints (common on input connectors but can be almost anywhere on the PCB, even with care mechanical shock from transporting takes it's tole)
the other suspect is intermittent ground or cracked solder joints (common on input connectors but can be almost anywhere on the PCB, even with care mechanical shock from transporting takes it's tole)
Odd that it quits when you mute the strings, I would think if it was a 100% problem with the internal amp the external source would not change it.
Like MAACO suggested try it with a source like a mic connected directly to the input.
Maybe input coupling caps, bad grounding, input buffer chip......
Like MAACO suggested try it with a source like a mic connected directly to the input.
Maybe input coupling caps, bad grounding, input buffer chip......
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Duplicate threads merged.bad grounds and vibrations from the loudspeaker that is in the same enclosure can produce all manner of noises like blats of distortion on transients to outright squealing with the right input stimulus.
quick test rather then play your guitar run some tunes and see if it shows any response to physical shock(yeah that right hit it...a few times even....it probably pissed you off because it crapped out at a gig) if it does then break out a magnifying glass and start a close examination of all solder joints.
the other thing to do is run it up on a "dim bulb tester" and see if your getting any sort of current increase when the distortion happens (i.e. the lamp brightness increases) would be a quick indication of larger issues (diodes or caps failing)
quick test rather then play your guitar run some tunes and see if it shows any response to physical shock(yeah that right hit it...a few times even....it probably pissed you off because it crapped out at a gig) if it does then break out a magnifying glass and start a close examination of all solder joints.
the other thing to do is run it up on a "dim bulb tester" and see if your getting any sort of current increase when the distortion happens (i.e. the lamp brightness increases) would be a quick indication of larger issues (diodes or caps failing)
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That sound is oscillation. Bad news is many things can cause it; good news is that some are easy to fix.
Troubleshoot from outside working inside. Check your connections: are you sure that if you wire up a good monitor in EXACTLY the same way with same cables and same devices that the problem is not there?
Next open it up and check all the jacks. Look for movement, damage, broken connections. Reflow all solder joints that look cold.
If all that doesn't find anything, you need to move deeper into the electronics: check voltages, components, etc.
Troubleshoot from outside working inside. Check your connections: are you sure that if you wire up a good monitor in EXACTLY the same way with same cables and same devices that the problem is not there?
Next open it up and check all the jacks. Look for movement, damage, broken connections. Reflow all solder joints that look cold.
If all that doesn't find anything, you need to move deeper into the electronics: check voltages, components, etc.
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