After a long search I found this great site.
I'm a poor student, trying to find a way to repair my beloved old hifi amp, and I thought maybe someone in this forum could help me out...
I have an old NAD 2200 power amp, and a NAD 1155 preamp. The problem is that the amp only plays in the right channel when just powered up. If I turn op loud the left channel works after some "scratching". When I turn the volume down again, it usually stops working in the left channel again.
The problem is related to the power amp, because it disappears if I change the power amp.
If I leave it on for several hours it works fine and plays great, but due to electricity useage that it not a convenient sollution.
So anyone has a comment on this? Any help would be much appreciated!!
Thanks.
I'm a poor student, trying to find a way to repair my beloved old hifi amp, and I thought maybe someone in this forum could help me out...
I have an old NAD 2200 power amp, and a NAD 1155 preamp. The problem is that the amp only plays in the right channel when just powered up. If I turn op loud the left channel works after some "scratching". When I turn the volume down again, it usually stops working in the left channel again.
The problem is related to the power amp, because it disappears if I change the power amp.
If I leave it on for several hours it works fine and plays great, but due to electricity useage that it not a convenient sollution.
So anyone has a comment on this? Any help would be much appreciated!!
Thanks.
I concur with most of the others here.
Scratching is most likely a potentiometer problem. Sometimes you can fix this temporarily by turning it all the way up and all the way down (amp turned off) a few times. If 5-10 times doesn't work you must clean it or replace it.
The "turn it up and it plays" problem is likely a speaker protection relay (usually a little black or blue box near the heatsinks).
Scratching is most likely a potentiometer problem. Sometimes you can fix this temporarily by turning it all the way up and all the way down (amp turned off) a few times. If 5-10 times doesn't work you must clean it or replace it.
The "turn it up and it plays" problem is likely a speaker protection relay (usually a little black or blue box near the heatsinks).
i don't recommend the inexperienced to open up pots, at least until they have practiced with a few from a junk parts box.
potentiometers have mechanisms that vary from manufacturer to manufacturer, and some manufacturers use different types of construction in their product lines. potentiometer rebuilding is an accquired skill. some pots use front pressure, some rear pressure, some use both, some use spring arms, some use wavy washers, etc....
it's good to get some practice before attempting to rebuild a pot in a working piece of equipment.
potentiometers have mechanisms that vary from manufacturer to manufacturer, and some manufacturers use different types of construction in their product lines. potentiometer rebuilding is an accquired skill. some pots use front pressure, some rear pressure, some use both, some use spring arms, some use wavy washers, etc....
it's good to get some practice before attempting to rebuild a pot in a working piece of equipment.
Have you tried a different preamp , because your description of your problem sounds like a preamp malfunction( volume control). Try to swap your left and right preamp output going to the amp around to see if the problem switches to the other channel.I'll bet it does! No sense tearing apart the amp if you dont have to.
It's definitely the relay. You'll notice Boas didn't say changing the volume made scratchy sounds, he said it makes those sounds when is is already turned up, and that it makes no sound at all in that channel when it is turned down. He also said changing the poweramp fixes it so it is clearly a power amp problem and not a preamp problem.
I've had the exact same problem on a few marantz amps. Usually if the relays are open, a good dusting and cleaning will fix it, if sealed you may need to replace them. It's the main reason I hate output protection relays!
I've had the exact same problem on a few marantz amps. Usually if the relays are open, a good dusting and cleaning will fix it, if sealed you may need to replace them. It's the main reason I hate output protection relays!
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