After something like 15 years active service both my Audiolab 8000P power amps have given up the ghost (original pre Tag Maclaren units). I am getting them repaired but I am wondering if it is likely/possible that both issues may actually have been caused by some other problem upstream in the pre-amp or the DAC (also Audiolab).
Why do I worry about this? Both amps failed in the same channel within about a week of each other which is kind of suspicious after such a long time of faultless service. I am sure the most likely cause is ageing components in the 800Ps, but maybe some deterioration is also happening earlier on in the audio chain and causing some kind of hideous spike that fried the power amps? Q: Is such a thing actually possible/likely?
Paranoid? Yes! It's not cheap to get the amps repaired and I don't want to screw them again as soon as they are returned if the real problem that blew the power amps may lie in the DAC or preamp. But I have no idea whether such a situation needs to be taken into account and precautions taken.
Any ideas?
Thanks!
Why do I worry about this? Both amps failed in the same channel within about a week of each other which is kind of suspicious after such a long time of faultless service. I am sure the most likely cause is ageing components in the 800Ps, but maybe some deterioration is also happening earlier on in the audio chain and causing some kind of hideous spike that fried the power amps? Q: Is such a thing actually possible/likely?
Paranoid? Yes! It's not cheap to get the amps repaired and I don't want to screw them again as soon as they are returned if the real problem that blew the power amps may lie in the DAC or preamp. But I have no idea whether such a situation needs to be taken into account and precautions taken.
Any ideas?
Thanks!
Its unlikely to be anything upstream of the power amps. If it were then you would be hearing major noises from the speakers first... I assume you didn't.
Failures can be 'from no outside contributing cause'. In other words something internal to the amp is amiss causing the product to fail.
Failure from 'external causes' would include shorting the speaker leads when the amp was playing (check for whiskers of wire at the speaker/and/or/ amp plus and sockets. Rarely something like a dodgy mains connections (loose wire in the plug top etc etc) might cause issues... again you would probably hear noises though.
Unlikely a spike or surge did any damage... the time constants are to large... it would have to spike of long duration to increase voltage within the amp.
Failures can be 'from no outside contributing cause'. In other words something internal to the amp is amiss causing the product to fail.
Failure from 'external causes' would include shorting the speaker leads when the amp was playing (check for whiskers of wire at the speaker/and/or/ amp plus and sockets. Rarely something like a dodgy mains connections (loose wire in the plug top etc etc) might cause issues... again you would probably hear noises though.
Unlikely a spike or surge did any damage... the time constants are to large... it would have to spike of long duration to increase voltage within the amp.
Thanks. Here is some further information just in case. The system was set up in bi-amped configuration.
There was no music playing when the first amp failed. Without warning it suddenly started emitting a constant and very loud electric buzzing noise. I happened to be in the room and immediately switched off the amp. After which the safety relays kicked in and the amp refused to switch on beyond "safe mode".
I removed the amp for repair and reverted to single power amp configuration for the interim. I played between 5-10 CDs over the next few days until the second one failed. Again there was no music playing at the time. I also happened to be in the room and this time heard a single short "audio fart" from the same channel. In this instance the amp does switch on again but only the other channel is active.
Does that info make any difference to the diagnosis? Just checking.
Otherwise thanks for the reassurance 🙂
There was no music playing when the first amp failed. Without warning it suddenly started emitting a constant and very loud electric buzzing noise. I happened to be in the room and immediately switched off the amp. After which the safety relays kicked in and the amp refused to switch on beyond "safe mode".
I removed the amp for repair and reverted to single power amp configuration for the interim. I played between 5-10 CDs over the next few days until the second one failed. Again there was no music playing at the time. I also happened to be in the room and this time heard a single short "audio fart" from the same channel. In this instance the amp does switch on again but only the other channel is active.
Does that info make any difference to the diagnosis? Just checking.
Otherwise thanks for the reassurance 🙂
Bi-amping shouldn't be an issue assuming its done correctly. By that I mean no unintentional cross coupling of speaker grounds for example (which could do stange things possibly) and just one channel of the amp feeding one speaker driver. Provided each amp is run within its limits (impedance wise) and not driven into gross clipping or overload then I can't really see bi-amping being an issue.
The fact you have a second amp that has also failed does set alarm bells ringing but the 'amp killers' remain the same for any amplifier. They fail either through a one off internal problem or something (the load hanging on the speaker sockets) pulling to much current. A problem with the audio input to the amp would cause damage again by the amp trying to deliver to much current and voltage into a given load... and you would be hearing anything that if it were happening.
The fact you have a second amp that has also failed does set alarm bells ringing but the 'amp killers' remain the same for any amplifier. They fail either through a one off internal problem or something (the load hanging on the speaker sockets) pulling to much current. A problem with the audio input to the amp would cause damage again by the amp trying to deliver to much current and voltage into a given load... and you would be hearing anything that if it were happening.
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