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McIntosh hum problem

Any of you MAC people own a MCD 751 CD Transport and MDA 700 D/A Converter combo? I do and both hum, wondered if any others with same problem? The converter hums louder and MAC gave me a new power transformer for it, but did not help. The hum is from the units themselves vs. speaker hum. Any way to reduce the hum. Any advice appreciated.
amwarwick
ljgj
955 posts
 
Check with Frank Gow at Audioclassics.com - he may be able to help or steer you in the right direction - they sell and refurbish Mcintosh equipment and have done so for years.
natalie
404 posts
 
Sounds like a ground loop.
aball
2,018 posts
 
Hi. I don't believe it has anything to do with the units themselves since they both do it. I would check grounding also (in your outlet wiring) and make sure that all points are connected to the same spot.
alexanderj
139 posts
 
Are the Mac's on a dedicated circuit? If not you may want to look at whatever else is plugged into that circuit. Some dimmers and motorized devices sometimes can be culprits. Especially suspect would be anything with a high/low switch in it. I had a room humidifier with said high/low switch and it made my velodyne subwoofer amp hum in the low setting.

Try unplugging suspect devices to see if you can locate a source for the hum.
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