Sub plate amp overheating question.

[kenmcculloch]

I've got a plate amp that works fine in testing but the plate gets VERY hot. Anyone have any suggestions on troubleshooting. I am NOT an electronics guy but I can unsolder and solder. Thanks.

[dthomas]

I've got a plate amp that works fine in testing but the plate gets VERY hot. Anyone have any suggestions on troubleshooting. I am NOT an electronics guy but I can unsolder and solder. Thanks.


How hot is very hot? Too hot to touch is not uncommon for many amplifiers. Most modern amps have thermal protection so if the amplifier circuit is overheating then it will shut itself down.

Since it appears they are using the back plate for thermal management the fact it is getting hot may just mean it is doing what it was expected to.

If it is too hot for your taste an option would be to add a finned heatsink to help pull heat off the plate. What amp is it?

[kenmcculloch]

Thanks for the reply. It is a Klipsch amp. I've got several other identical amps I was checking to see if they worked and they didn't heat up like this one. It is too hot to touch. None of the amps have heat sinks. I can take a photo. The amp heated up immediately when I turned it on.

[Dirk]

Load connected or no load?

[dthomas]

Thanks for the reply. It is a Klipsch amp. I've got several other identical amps I was checking to see if they worked and they didn't heat up like this one. It is too hot to touch. None of the amps have heat sinks. I can take a photo. The amp heated up immediately when I turned it on.

Are you sure it is 4 ohm stable? I would really doubt it does not have thermal protection. So too hot to touch is not really uncommon.

Does it didstort or clip easily? If it does not and you would prefer it to be cooler you can always add a large finned heatsink which would help it to dissipate heat better.

High heat in an amplifier is an indication that it is producing a lot of power, what you need to determine is it dissipating more power than it was designed to dissipate. Hot is common in an amplifier and is the product of making power.

[kenmcculloch]

During my check out I had a 4 ohm speaker hooked up (no cabinet) and the sound was fine - no breakup or distortion. I wasn't pushing the amp volume (or my receiver volume) at all. I'm not sure if this amp is for a 4 ohm load but the other identical amps didn't get hot at all into the same 4 ohm speaker for the same length of time tested.

[Dirk]

I'd be curious to know how many volts DC you register when a speaker is connected and no music is playing.

[philiparcario]

1 possibility is the plates are not the same. all are 4 ohm (rated) except the hot one 8 ohm (rated) .. if You fully dissasembled the same "plates" 1 or two Parts could make a difference. A smaller power cap and a smaller transformer, could be the problem.

[kenmcculloch]

I'll test it tonight with an 8 ohm woofer and see if I can get a DC volts reading. Thanks.

[kenmcculloch]

Just got info from Klipsch. This amp was used in the KSW 10 subwoofer and is rated at 55wpc. They didn't know the impedance of the woofer but I'll bet my hat it is 4 ohms. See below info from the Klipsch website.

POWER HANDLING FTC Rated Power: 55 watts continuous,
22-125Hz @ ≤ 1% THD
Dynamic Power*: 225 watts @ ≤ 1% THD
*Dynamic power indicates the actual power this amplifier will deliver to the woofer under normal operating conditions. While the FTC power rating indicates power available on a continuous, long-term basis, subwoofers do not rely on that type of power. Instead, the amplifier is called upon to deliver large, short-term peaks of power to be able to support the wide dynamics required by today's digital music and movie formats. In addition to the required FTC power rating, we've provided the dynamic power rating as a better indication of the product's true performance