Nakamichi PA-7 Hum


Hi,
Hope everyone has a great holiday season.
I am the original owner of a PA-7. If my house was ever robbed the first place I would look to know if my life, as I have known it, was over is my audio rack. I will stay with the PA-7 until it dies or I do.
My problem is that any new equipment that I try to run through the preamp (Nakamichi CA-5)that is not CD related i.e. cable TV audio lines, dvd players - anything new makes the amp hum. It is loud enough to be annoying but is drowned out when the volume is loud enough. Needless to say I have never left anything connected to it that caused it to hum for fear of doing damage.
Any ideas why it does that and if there is some type of line filter that I should have and don't know about? I would love to play DVD's, cable, etc. through the PA-7 but as long as I have had it only CD's play through without a problem.
Thanks for any help.
edmallia

Showing 1 response by marakanetz

With time the internal power supply of the amp may become noisy due to the lack of DC filtering. If this is the case you'll need to inspect PCB for the loose soldering joints and replace power supply electrolytic capacitors.