hi everybody,
I've been using a RA-1570 amp for several years and I'm delighted with the way it sounds... however it's been a few months since a relay has been triggered accidentally and switches very quickly to the rithme of the music (on the bass impulses) as soon as I exceed a certain sound level and it doesn't matter what the input (analog or digital) or the output (Speaker A or B) is.
The restitution of the music is not affected, I do not have any cut of the sound signal. In addition this problem is not present at low sound levels or if I do not connect speakers to outputs.
This is rather worrying considering that the disturbance seems to be caused directly by the power signal transmitted to the speakers. 🙁
I would like to point out that the amplifier chassis is properly grounded.
I have tried to locate the relay responsible for this noise but without any real success as it seems to be on a hidden and not directly accessible part after removing the cover. I'm rather resigned because I didn't receive any answer from the SAv of rotel 😡
So I'm going back to your knowledge in the hope of getting some leads to follow in order to locate and eventually solve the problem.
Have you ever encountered this type of problem on a integrated amplifier of this type? What do you advise me to check or investigate?
I thank you in advance for the help you can give me.
Have a nice evening.
I've been using a RA-1570 amp for several years and I'm delighted with the way it sounds... however it's been a few months since a relay has been triggered accidentally and switches very quickly to the rithme of the music (on the bass impulses) as soon as I exceed a certain sound level and it doesn't matter what the input (analog or digital) or the output (Speaker A or B) is.
The restitution of the music is not affected, I do not have any cut of the sound signal. In addition this problem is not present at low sound levels or if I do not connect speakers to outputs.
This is rather worrying considering that the disturbance seems to be caused directly by the power signal transmitted to the speakers. 🙁
I would like to point out that the amplifier chassis is properly grounded.
I have tried to locate the relay responsible for this noise but without any real success as it seems to be on a hidden and not directly accessible part after removing the cover. I'm rather resigned because I didn't receive any answer from the SAv of rotel 😡
So I'm going back to your knowledge in the hope of getting some leads to follow in order to locate and eventually solve the problem.
Have you ever encountered this type of problem on a integrated amplifier of this type? What do you advise me to check or investigate?
I thank you in advance for the help you can give me.
Have a nice evening.
If there's a big DC offset the protection circuit will trigger on large bass waveforms in the same direction, but also your loudspeakers are in danger from the high DC current through them, so unplug them first - them measure the offset voltage on each channel.
I suspect one of them is out by a largish margin for these symptoms. DC offset should be a small fraction of a volt, a few millivolts is great.
I suspect one of them is out by a largish margin for these symptoms. DC offset should be a small fraction of a volt, a few millivolts is great.
Thanks for the advise, i have checked DC voltage on the outputs, i have arround 3mV on both channel. I reconnected my speakers just after and curiously, the problem does not seem to be recurring at the moment, whereas I had it systematically before.
I enjoyed that my amp worked correctly to listen to music via my pc (in usb) and I had a good HF noise continuously in the speakers (while the source was off, I was not streaming music). It was while using this source that the problem started to appear so I immediately unplugged the usb cable. By the way, I have the impression that the relay that panics is the same as the relay that switches when a usb cable is connected.
I'm gonna do without the damn usb in doubt and I hope this problem doesn't happen again.
I enjoyed that my amp worked correctly to listen to music via my pc (in usb) and I had a good HF noise continuously in the speakers (while the source was off, I was not streaming music). It was while using this source that the problem started to appear so I immediately unplugged the usb cable. By the way, I have the impression that the relay that panics is the same as the relay that switches when a usb cable is connected.
I'm gonna do without the damn usb in doubt and I hope this problem doesn't happen again.
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Thanks for your advises, i have checked the DC Voltage of the Output, it seems to be arround 3mV on each channel.
I reconnected myspeakers right after and the problem seems to have mysteriously disappeared for now.
I took advantage of the fact that my amp was running correctly to listen to music via my pc (in usb) and I had a good HF noise continuously in the speakers (while the source was off, I was not streaming music). It is by using this source that i met this problem first so so I immediately unplugged the usb cable. By the way, I have the impression that the relay that panics is the same as the relay that switches when a usb cable is connected.
So I'm gonna do without this damn usb connection hoping the problem doesn't happen again.
I reconnected myspeakers right after and the problem seems to have mysteriously disappeared for now.
I took advantage of the fact that my amp was running correctly to listen to music via my pc (in usb) and I had a good HF noise continuously in the speakers (while the source was off, I was not streaming music). It is by using this source that i met this problem first so so I immediately unplugged the usb cable. By the way, I have the impression that the relay that panics is the same as the relay that switches when a usb cable is connected.
So I'm gonna do without this damn usb connection hoping the problem doesn't happen again.
3 mV sounds pretty good for a power amp.
Usually a DC protection circuit works by rectifying the output waveform and measuring the rectified voltage. If the voltage exceeds some threshold, the output relay opens. The output of the rectifier is lowpass filtered to prevent the relay from opening during operation.
I bet the capacitor in that lowpass filter has dried out and needs replacement. If you can dig up the schematics for the amp, I can help you identify the capacitor.
Tom
Usually a DC protection circuit works by rectifying the output waveform and measuring the rectified voltage. If the voltage exceeds some threshold, the output relay opens. The output of the rectifier is lowpass filtered to prevent the relay from opening during operation.
I bet the capacitor in that lowpass filter has dried out and needs replacement. If you can dig up the schematics for the amp, I can help you identify the capacitor.
Tom
Ok, thanks for your explanation Tom, I was not aware of the that.
I've already asked rotel if they could provide me with some hardware docs for the amp but I'm still waiting for a feedback from them, after several reminders from their website.
Whithout any hardware schematics it might be difficult to locate the component in question.
If the problem happens again, I can remove the input card (the one with the connectors on the back side), and take a look at what's below. Do you know where this protection usually lies?
Thank you in advance
I've already asked rotel if they could provide me with some hardware docs for the amp but I'm still waiting for a feedback from them, after several reminders from their website.
Whithout any hardware schematics it might be difficult to locate the component in question.
If the problem happens again, I can remove the input card (the one with the connectors on the back side), and take a look at what's below. Do you know where this protection usually lies?
Thank you in advance
Another common cause of such symptoms is resistors in the output stage (usually around the outputs or drivers) that have gone bad (high). Definitely worth checking for. These are usually hard to miss, being 2, 3 or 5 W types near where the action happens. 😉
BTW, this one should be in Solid State.
BTW, this one should be in Solid State.
I do no think that this has anything to do with the output DC protection.
A. 3mV do not trigger it
B. the music does not cut out with the clicking.
So it will not be the loudspeaker relay. Sorry.
If you have access to compressed air, open the amp and blow any dust from and out of any component. Don´t blow parts away or bend anything. Compressed air is strong!
Vacuum cleaning is not very useful and even using a soft paint brush can damage stuff.
If the problem reappears, post again.
Good luck!
A. 3mV do not trigger it
B. the music does not cut out with the clicking.
So it will not be the loudspeaker relay. Sorry.
If you have access to compressed air, open the amp and blow any dust from and out of any component. Don´t blow parts away or bend anything. Compressed air is strong!
Vacuum cleaning is not very useful and even using a soft paint brush can damage stuff.
If the problem reappears, post again.
Good luck!
Exactly the same issue here! But only on the right channel. If I play with only the left loudspeaker connected the clicking does not happen. Have not been able to get hands on the service manual 🙁 Like a year ago it came and went and now I always get the clicking noice from the amp when the output wattage reach a certain level. Any ideas?