My Denon PMA-280 started to occasionally play at lower volume and to occasionally produce crackle in the right channel. The crackle doesn't happen by itself, but only with a signal, most easily heard with a sine wave.
I'm attaching a recording of the crackle with a 60Hz sine wave playing. I'm changing the volume a little bit throughout the recording. The crackle is more or less intense at different volumes, but this varies wildly over time. It's not the volume pot that's causing it, because it happens with the changes in input volume as well.
I can hear it through the headphones output too, but only if a load is present on the speaker out (a speaker or a resistor). Without that load, it sounds just fine on headphones.
I've read in some other threads that you can find the faulty component by freezing them, but I'm clueless about this stuff and I was hoping at least to get some pointers and to narrow down the issue. I also have a multimeter I could use to measure something, if it helps.
I'm attaching a recording of the crackle with a 60Hz sine wave playing. I'm changing the volume a little bit throughout the recording. The crackle is more or less intense at different volumes, but this varies wildly over time. It's not the volume pot that's causing it, because it happens with the changes in input volume as well.
I can hear it through the headphones output too, but only if a load is present on the speaker out (a speaker or a resistor). Without that load, it sounds just fine on headphones.
I've read in some other threads that you can find the faulty component by freezing them, but I'm clueless about this stuff and I was hoping at least to get some pointers and to narrow down the issue. I also have a multimeter I could use to measure something, if it helps.
Thanks, I think you're probably right! Tapping on it now while there was no crackling made the crackling appear briefly. Unless something in the vicinity got triggered by this tapping, I guess that's possible too...
This problem is intermittent, so I'll check again when it's more severe.
Does this part need to be replaced or can it be repaired?
Alright thanks, hopefully I can find that part.
I also remembered now that this Denon always had a long delay (about 6 seconds) between turning it on and the relay click, ever since I got it a few months ago. Does this also point to a problem with the relay or is 6 seconds normal for this amp?
I also remembered now that this Denon always had a long delay (about 6 seconds) between turning it on and the relay click, ever since I got it a few months ago. Does this also point to a problem with the relay or is 6 seconds normal for this amp?
No, that is within the normal range.
The delay is to allow everything to settle in the receiver. That includes DC offsets and time for fault detection. Some components take a lot longer. I haven't timed it, but I bet my Luxman C-05 preamp takes 20 seconds to come out of mute. Now that is excessive!
That relay can be found at Digikey, it isn't an abnormal part at all. Other vendors will also carry it.
The delay is to allow everything to settle in the receiver. That includes DC offsets and time for fault detection. Some components take a lot longer. I haven't timed it, but I bet my Luxman C-05 preamp takes 20 seconds to come out of mute. Now that is excessive!
That relay can be found at Digikey, it isn't an abnormal part at all. Other vendors will also carry it.