Tweeter is hot.

[mateematy]

Hello, I have a pair of Adam T5V and suddenly one tweeter started being hot while being plugged in. Should I be worried ?

 

[HarmonicTHD]

Hello, I have a pair of Adam T5V and suddenly one tweeter started being hot while being plugged in. Should I be worried ?

Yes. Contact Adam. Can you say more?

 

[solderdude]

Hello, I have a pair of Adam T5V and suddenly one tweeter started being hot while being plugged in. Should I be worried ?

Either there is some HF signal being passed on to the tweeters coming from the source (would probably be at both speakers).
or
Something is oscillating or a DC is present on the tweeter in which case it would only involve one speaker.

When the speaker is switched on and not connected to anything other than mains is the tweeter still getting hot ?
If so (and it is on one speaker only) electronics have failed.
When it stays cold I would look at the audio chain before blaming the speaker.

 

[mhardy6647]

The notion of a tweeter getting hot a priori is terrifying.
Knowing nothing about this particular product, I am wondering if it's getting hot by association -- the interior electronics are getting toasty enough that the tweeter's escutcheon is getting "hot by association"? Assuming, of course, that the tweeter's chassis, so to speak, is metal and is able to conduct heat, and not, e.g., plastic.

If one is hot and the other not, and if this is a recent development -- it sounds very bad to me.

I do like @solderdude's notion in the abstract -- were it me, I'd consider* disconnecting the signal input cable, turning on the offending loudsepeaker and
see if it happens sans input.

______________
* I would consider it, but I'd also seriously consider unplugging the 'bad' loudspeaker and never powering it up again until and unless it were gone over by someone who knew what "they" were doing!

 

[mateematy]

Yes. Contact Adam. Can you say more?

My speakers are connected to a Scarlett 2i2 via balanced connection. To be more specific, if you look up pictures on the internet of the speakers, the three lines of the tweeter are the ones which are getting hot to the touch and the "cone" or "walls" of the tweeter are just warm.

 

[HarmonicTHD]

My speakers are connected to a Scarlett 2i2 via balanced connection. To be more specific, if you look up pictures on the internet of the speakers, the three lines of the tweeter are the ones which are getting hot to the touch and the "cone" or "walls" of the tweeter are just warm.

Could you please post a picture so we avoid confusion about what exactly is getting hot?

 

[mateematy]

When the speaker is switched on and not connected to anything other than mains is the tweeter still getting hot ?
If so (and it is on one speaker only) electronics have failed.
When it stays cold I would look at the audio chain before blaming the speaker.

I will try this and come back with feedback. What do you mean by electronics ? The dac or the speaker's electronics ?

 

[mateematy]

Could you please post a picture so we avoid confusion about what exactly gets hot?

Best I can do

 

[mhardy6647]

Much confusion here (or maybe it is just me), perhaps language-related?
1) So, this seems to be the culprit (random internet image)?

2) I assume that the tweeter only gets hot when the speaker is plugged in to AC mains and turned on?
Is this assumption correct?


3) what is getting hot? The tweeter's faceplate, the tweeter 'diaphragm', the metal around the tweeter diaphragm, or something else?

if you look up pictures on the internet of the speakers, the three lines of the tweeter are the ones which are getting hot to the touch and the "cone" or "walls" of the tweeter are just warm.

4) "The three lines of the tweeter" do you mean wires inside the box or the tweeter faceplate (behind the "waveguide")?
I am now guessing the latter(?).

EDIT: Yup, apparently just the faceplate of the tweeter.
Sounds like not a good thing to me.

5) So... hot... to me, hot is probably circa 50 degrees C (or, of course more). Do you have an IR thermometer, @mateematy ?

 

[fpitas]

DC to the tweeter maybe? Otherwise, if it was high frequencies you'd have no eardrums left.

 

[mhardy6647]

I assume that behind the "waveguide" the tweeter itself looks more or less like this cheap AMT tweeter from PartsExpress (?)

 

[fpitas]

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?

 

[mhardy6647]

DC to the tweeter maybe? Otherwise, if it was high frequencies you'd have no eardrums left.

I am guessing the tweeter wouldn't last very long at all with DC on the "voicecoil" (or whatever the equivalent electrically conductive bit in an AMT is), though.
The tweeter could be pumping its heart into striving to reproduce ultrasonic oscillation -- if so, a house pet (dog) or a passing bat might be a good analytical tool Of course, an oscilloscope would work, too, and I don't think that oscilloscopes have been shown to be vectors for rabies.

borrowed from http://www.radiomanual.info/schemi/KENW_ACC/Trio_CS-1577A_user.pdf

@fpitas's post does indeed suggest another good troubleshooting question: Does the hot tweeter still work?
(i.e. does sound come out of it?)

 

[fpitas]

If some frequency wayyy above its passband was going there that might indeed do it. In any event, it's broken.

 

[mhardy6647]

OK, could be heterodyne (beating) or mixing, I s'pose, if there were ultrasonic oscillation (i.e., if the amplifier has failed to work properly). Do these loudspeakers use class D (pulse-width modulation) amplification?

 

[HarmonicTHD]

Why don’t you contact and ask Adam? If you are still within warranty they need to fix or replace it anyhow.

 

[mhardy6647]

 

[fpitas]

OK, could be heterodyne (beating) or mixing, I s'pose, if there were ultrasonic oscillation (i.e., if the amplifier has failed to work properly). Do these loudspeakers use class D (pulse-width modulation) amplification?

Could be the unfiltered switching pulses. In any event, it's quite broken and needs repair.

 

[mateematy]

Much confusion here (or maybe it is just me), perhaps language-related?
1) So, this seems to be the culprit (random internet image)?

Yes. I am not that familiar with the correct terms.

2) I assume that the tweeter only gets hot when the speaker is plugged in to AC mains and turned on?
Is this assumption correct?

Yes.

4) "The three lines of the tweeter" do you mean wires inside the box or the tweeter faceplate (behind the "waveguide")?
I am now guessing the latter(?).

EDIT: Yup, apparently just the faceplate of the tweeter.
Sounds like not a good thing to me.

I hope you understood from my drawing.

5) So... hot... to me, hot is probably circa 50 degrees C (or, of course more). Do you have an IR thermometer, @mateematy ?

No unfortunately.

 

[mhardy6647]

I think the emerging consensus is pretty clear.

• There is something wrong with the unit.
• It would be fascinating to at least some of us to figure out the root cause, or at least the "proximate cause" of the heating, but...
• It needs to be repaired or replaced (the former if there's a warranty, almost certainly the latter if not).

This being said, the one - arguably - loose end, from my perspective*, is whether or not the tweeter would get hot if no signal is fed to it.
I am not sure it's worth testing this and exposing the unit to an opportunity to suffer even more damage, but it might (???) be a good idea to determine that the problem does indeed isolate to the active speaker unit itself, and not to something "upstream" of it.

__________
* and per this question from the @mateematy

I will try this and come back with feedback. What do you mean by electronics ? The dac or the speaker's electronics ?