I have a supercube II from Definitive tech. The sub makes a thwack noise when run hard, especially over time. I purchased a replacement amp from def tech and it was better for a while and then returned. I supposes it's possible the sub is the problem, but is there a good way to troubleshoot the amp? The driver made no noise when "tested" in free air at a lower wattage, but I realize that may not have pushed it hard enough or got it hot enough. I don't have a good spare driver, nor do I have a high wattage resistor. I do have volt ohm meters and an oscilloscope. Thoughts on best procedure?
Adam
Adam
Speaker cabinet is sealed. Unfortunately I do not have the schematic. However I do have an amp just hanging out. Looks like it has three sections, signal processing, amplification and power/AC to DC. I can post pictures if they will help.
I also thought that the driver sounded like the issue, but it didn't make noise in free air and Definitive tech tech thought it sounded like the amp when the driver didn't do it in free air.
I also thought that the driver sounded like the issue, but it didn't make noise in free air and Definitive tech tech thought it sounded like the amp when the driver didn't do it in free air.
1. Please post some detailed pictures of the board.
2. First you need to make sure that the power supply is working.
Could you measure all the voltages out of the power supply and post them here ?
Also, can you display them on your scope to measure the ripple ?
You can use AC coupling. Also post pictures here.
2. First you need to make sure that the power supply is working.
Could you measure all the voltages out of the power supply and post them here ?
Also, can you display them on your scope to measure the ripple ?
You can use AC coupling. Also post pictures here.
Below will be links of the video from my test and pictures. If someone would like a more specific picture, let me know. I'm beginning to wonder if the main level/volume knob has anything to do with it, during certain regions of it, the issue was produced more frequently. Hopefully you can hear the noise on the video. Also, possibly of note, the sub had a bit of an odor after the test, not the amp or input board, but the driver. Let me know if anyone has any ideas.
Adam
https://cadamwil.smugmug.com/Supercube-2-troubleshooting
https://youtu.be/p1Uw3KP_Hfs
Adam
https://cadamwil.smugmug.com/Supercube-2-troubleshooting
https://youtu.be/p1Uw3KP_Hfs
Ok, I was worried I was an idiot and the pots were nasty, and causing my issue. So I found some Deoxit in town and cleaned the pots. Same stuff. Possibly of note, it seemed much improved for a minute and then got worse. Any ideas? Does everyone think it's a driver or maybe the input/control board? Driver is $70 + shipping, no clue on the input/control board.
Adam
Adam
Noisy pots have been observed to be staticy especially if a circuit passes DC through them.
A known cause of pops in Class D is if the feedback loop gets out of control, which might happen during clipping, depending on the circuit design. Other than saying something general, even though I wasn't a bad repair tech in my day, I often had to just do my own physical hands-on troubleshooting to diagnose problems.
A known cause of pops in Class D is if the feedback loop gets out of control, which might happen during clipping, depending on the circuit design. Other than saying something general, even though I wasn't a bad repair tech in my day, I often had to just do my own physical hands-on troubleshooting to diagnose problems.
In your video, did you move the volume potentiometer in order to vary the output volume ?
If so, the first thing I would look at is the potentiometer and its surrounding area.
Please check for the following:
-bad contacts on the pot
-cold solder joints on the pot or on the components nearby
-mechanically weak (deformable) surroundings
If nothing obvious appears I would replace the pot with a new one and redo all the solder joints around it.
If there is a capacitor nearby, I would replace that too.
If these steps do not solve it the problem might be more complex.
Let us know what you find. If possible please post another video and detailed pictures of the area around the pot.
If so, the first thing I would look at is the potentiometer and its surrounding area.
Please check for the following:
-bad contacts on the pot
-cold solder joints on the pot or on the components nearby
-mechanically weak (deformable) surroundings
If nothing obvious appears I would replace the pot with a new one and redo all the solder joints around it.
If there is a capacitor nearby, I would replace that too.
If these steps do not solve it the problem might be more complex.
Let us know what you find. If possible please post another video and detailed pictures of the area around the pot.
Ehh, not yet. A friend of mine came over and gave it a look as well. His suggestion was to use a different speaker for the test. I had been reluctant to do this as the amp is a 1000 watt class D amp, and figured it would push any full range speakers hard enough to pop by the time I got the level up to the same level that I was seeing issue at. Anyway, had a set of speakers in the garage that wouldn't ruin my month if they died. Tried one of them, by dropping the source level I got the amp gain at similar levels and didn't hear the issue. Current suspect is the woofer/driver. Waiting on Definitive's guess with the video and the info on using another speaker.
noise from DT Supercube II
Hey Adam, can you shed some light on the noise I am getting on my sub. It is the same noise from the YouTube video starting at about 3:10-3:28.
The noise is exactly what I am getting.
Thanks in advance,
Alfred
Below will be links of the video from my test and pictures. If someone would like a more specific picture, let me know. I'm beginning to wonder if the main level/volume knob has anything to do with it, during certain regions of it, the issue was produced more frequently. Hopefully you can hear the noise on the video. Also, possibly of note, the sub had a bit of an odor after the test, not the amp or input board, but the driver. Let me know if anyone has any ideas.
Adam
https://cadamwil.smugmug.com/Supercu...roubleshooting
https://youtu.be/p1Uw3KP_Hfs
Hey Adam, can you shed some light on the noise I am getting on my sub. It is the same noise from the YouTube video starting at about 3:10-3:28.
The noise is exactly what I am getting.
Thanks in advance,
Alfred
Below will be links of the video from my test and pictures. If someone would like a more specific picture, let me know. I'm beginning to wonder if the main level/volume knob has anything to do with it, during certain regions of it, the issue was produced more frequently. Hopefully you can hear the noise on the video. Also, possibly of note, the sub had a bit of an odor after the test, not the amp or input board, but the driver. Let me know if anyone has any ideas.
Adam
https://cadamwil.smugmug.com/Supercu...roubleshooting
https://youtu.be/p1Uw3KP_Hfs
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