Amp thermal shutdown?
Discussion
I have a Denon AV amp connected to 2 Cambridge Audio speakers and a separate sub. Yesterday while having a bit of time with the house to myself and the volume turned up (circa 80-85/100 on the amp) it cut out, and felt very hot near the volume control (presumably there is resistor behind there somewhere)? The Denon website says this which I dont really understand...
'If the protection light came on due to a speaker wire short, low impedance condition or a bad speaker, the receiver's power will need to be turned off to reset it.'
My system has only just been set up again, so is it possible that something has either not gone back together properly, or got damaged? If not, what does low impedance mean?
'If the protection light came on due to a speaker wire short, low impedance condition or a bad speaker, the receiver's power will need to be turned off to reset it.'
My system has only just been set up again, so is it possible that something has either not gone back together properly, or got damaged? If not, what does low impedance mean?
The lower the impedance the closer a circuit gets to short-circuit condition which is never a good thing for an amplifier.
My guess is you’re pushing the amp far too hard and housing it in an enclosed space and, at that sort of volume, I suspect an over-temp circuit has tripped to protect the amplifier.
A few options:
House the amp where it will get better airflow.
Go easier with the volume (I’m used to amps that give their best before reaching 50% on their volume controls - running it at 80%, especially with modern brick walled CDs makes my teeth itch.
Get a more powerful amp.
Get more sensitive speakers (higher sensitivity will give a louder level for a given input level).
What model is the amp and speakers?
Edited to add: are you connecting speakers to amp using twisted bare wire?
If so, remove and reconnect making sure no stray ends are touching the case or another output terminal.
If using banana plugs, check for the same and re-tighten them.
My guess is you’re pushing the amp far too hard and housing it in an enclosed space and, at that sort of volume, I suspect an over-temp circuit has tripped to protect the amplifier.
A few options:
House the amp where it will get better airflow.
Go easier with the volume (I’m used to amps that give their best before reaching 50% on their volume controls - running it at 80%, especially with modern brick walled CDs makes my teeth itch.
Get a more powerful amp.
Get more sensitive speakers (higher sensitivity will give a louder level for a given input level).
What model is the amp and speakers?
Edited to add: are you connecting speakers to amp using twisted bare wire?
If so, remove and reconnect making sure no stray ends are touching the case or another output terminal.
If using banana plugs, check for the same and re-tighten them.
Edited by legzr1 on Sunday 4th March 18:32
Edited by legzr1 on Sunday 4th March 18:32
The amp has a pre-out for the active sub, other than that its just powering 2 passive speakers.
Its currently sat on top of a unit, so airflow shouldnt be an issue.
Amp is a Denon AVR-X250BT, which I would have though would have driven the 2 Cambridge Audio S30 bookcase speakers, maybe its not powerful enough though.
Will have a fiddle with the connections and see if that fixes it, but the top of the amp felt hot, so suspect that is the issue.
Its currently sat on top of a unit, so airflow shouldnt be an issue.
Amp is a Denon AVR-X250BT, which I would have though would have driven the 2 Cambridge Audio S30 bookcase speakers, maybe its not powerful enough though.
Will have a fiddle with the connections and see if that fixes it, but the top of the amp felt hot, so suspect that is the issue.
I've done a quick search for data on your amp and speakers, and the amp is designed for speakers with an impedance of 6 to 16 ohms, and the speakers have an impedance of 4 to 8 ohms. So, at certain sound frequencies, the speakers 'can' draw too much current from your amp. The higher the volume setting, the higher the chance of this happening.
Typically, Japanese amps prefer 8 ohm speakers.
If your speakers are very old, the coils 'might' have deteriorated, and this can exacerbate the above problem.
Typically, Japanese amps prefer 8 ohm speakers.
If your speakers are very old, the coils 'might' have deteriorated, and this can exacerbate the above problem.
Edited by Tony1963 on Tuesday 6th March 20:21
mike_e said:
Is the Red LED flashing when it powers off? Slow flash (2 secs) = overheat, fast flash = failure.
Slow flash. Thanks to everyone, its defiantly overheating, presumably because the speakers are drawing too much power. If I turn the input volume down on whatever device is aux-ed into the amp its much better behaved no matter what the output volume is doing. The speakers are due an upgrade at some point anyway, so will look for ones with a higher ohm rating.
Edit - I wonder why the S30's are only 4 ohm, the S50's, their replacement, are 8 ohm. Looks like an excuse to upgrade them....
Edited by Condi on Thursday 8th March 23:06
Gassing Station | Home Cinema & Hi-Fi | Top of Page | What's New | My Stuff