Posting this here as not DIY related. Just a heads-up on what happened to one of my Wharfedale D-220 speaker drivers. I got a cheap class-D amp for the workbench to save some space 2 years ago, it only sees light usage and has been fine until I was awoken by a smoke alarm early this morning. No noticeable smoke or smell but the alarm would not reset, I turned the mains power off as a precaution and hit the sack. Fired up the bench this morning and noticed one speaker was down, opened it up and this was the result:
The driver magnet obviously got hot, melted the cage and sagged trapping the voice coil. checked the amp, full 18v of the PSU on one channel. The driver voice coil is slightly discoloured but not as much as I would have expected to reach that temp'.
Nothing obvious on the amp pcb, nothing bulging chipped or charred, it still worked fine when I clipped a 2200uF blocking cap on the output. Can't be bothered tracing the fault, The enclosure will be repurposed with my own TDA2009a amp circuit. Scratch one Wharfedale D1119 driver.
The driver magnet obviously got hot, melted the cage and sagged trapping the voice coil. checked the amp, full 18v of the PSU on one channel. The driver voice coil is slightly discoloured but not as much as I would have expected to reach that temp'.
Nothing obvious on the amp pcb, nothing bulging chipped or charred, it still worked fine when I clipped a 2200uF blocking cap on the output. Can't be bothered tracing the fault, The enclosure will be repurposed with my own TDA2009a amp circuit. Scratch one Wharfedale D1119 driver.
Yikes! Might have been worse if not for that smoke alarm?
What was the “cheap class D amp”? One of those AIYAMA TPA3255 300x2 things? Or something else ? I’ve been using these things as zone 2+ amps in client installs…
What was the “cheap class D amp”? One of those AIYAMA TPA3255 300x2 things? Or something else ? I’ve been using these things as zone 2+ amps in client installs…
Thats probably the lesser of the class d chips what is it 3116? I would've thought they would have dc protect at the minimum to stop the speaker damage blowback.
This is not one of the Texas Instruments chips, but a Chinese 3116 clone notorious for unprovoked failure.
While the sound is not too bad if compared in low budget set ups, it has none of the sophisticated safety features of the TI products.
QED
While the sound is not too bad if compared in low budget set ups, it has none of the sophisticated safety features of the TI products.
QED