Thanks @kapitiaudio for your comments. The tech's feedback was that the relays and the driver IC look OK. I am not sure if they checked the thermal switches. I did mention to them about how the amp's relay clicked pretty much immediately when used every day or every other day, but displayed a significant delay when operated after more than 3 days or thereabouts. As much as the lads at NAD want to fix the older amps, they are limited by the resources given to them to diagnose these issues properly. I believe it is a policy issue more than anything.
Thanks @Mooly for the reply. Sorry about not responding earlier, as I had something urgent to attend to. I have to report to you that something else happened with the amp.
Yesterday, I powered ON the amp, and it took around slightly more than 1 minute for the relay to click. The preamp had the volume set to 'mute'. When the relay clicked, the LED did not change to GREEN but remained AMBER. I could hear hisses and buzzes from the drivers. I believe it was not loud because the volume was set to mute. I switched OFF the amp immediately.
I waited a few minutes and powered it up again. This time, the relays clicked within a few seconds, but the LED still remained AMBER. With a second or two, there was another click. Still, the LED remained AMBER, but a loud pop went off in my speakers. I switched it OFF immediately.
I have not encountered this in the past. This is the first time I am seeing the amp's relay clicking and the LED remaining AMBER. Usually, it clicks(regardless of the time it takes) and the LED will be GREEN.
Wondering if I had blown by drivers, again, I disconnected the speakers from the amp and plugged them directly into my preamp/streamer. Appears to be OK.
Thanks @Mooly for the reply. Sorry about not responding earlier, as I had something urgent to attend to. I have to report to you that something else happened with the amp.
Yesterday, I powered ON the amp, and it took around slightly more than 1 minute for the relay to click. The preamp had the volume set to 'mute'. When the relay clicked, the LED did not change to GREEN but remained AMBER. I could hear hisses and buzzes from the drivers. I believe it was not loud because the volume was set to mute. I switched OFF the amp immediately.
I waited a few minutes and powered it up again. This time, the relays clicked within a few seconds, but the LED still remained AMBER. With a second or two, there was another click. Still, the LED remained AMBER, but a loud pop went off in my speakers. I switched it OFF immediately.
I have not encountered this in the past. This is the first time I am seeing the amp's relay clicking and the LED remaining AMBER. Usually, it clicks(regardless of the time it takes) and the LED will be GREEN.
Wondering if I had blown by drivers, again, I disconnected the speakers from the amp and plugged them directly into my preamp/streamer. Appears to be OK.
By drivers you mean the transistors in the amp, not the speaker drive units?
If the transistors then it doesn't sound good tbh. Everything points to an underlying issue with the amp that may have become more destructive.
As always checks on DC offset before the relay need to be done.
@Mooly Hello Mooly. Thanks for the quick reply. It was the speaker drive units. If I had not set the 'mute' switch ON on the preamp, I think this would have really loud. This will go back to NAD next week. If they can't fix this, I will send it out to a local tech. In the meantime, I am looking to order this scope:
https://www.amazon.com/Hantek-DSO2C...47233506&sprefix=oscilo,aps,1124&sr=8-12&th=1
Do you think this would be enough to get around fixing this amp? Or is it overkill? I might even bring this to them 🤣 . Unbelievable, it is, Mooly. I was so glad and pumped up after the initial fix.
https://www.amazon.com/Hantek-DSO2C...47233506&sprefix=oscilo,aps,1124&sr=8-12&th=1
Do you think this would be enough to get around fixing this amp? Or is it overkill? I might even bring this to them 🤣 . Unbelievable, it is, Mooly. I was so glad and pumped up after the initial fix.
A scope like you show is OK for basic audio work... its fine for that 🙂
Your latest problems are probably more fundamental and initially at least back into traditional faultfinding with a meter. You have to check the basics (the DC conditions first) now the fault has gone to what you have now.
Your latest problems are probably more fundamental and initially at least back into traditional faultfinding with a meter. You have to check the basics (the DC conditions first) now the fault has gone to what you have now.