Beauregard
100+ Head-Fier
- Joined
- Feb 17, 2003
- Posts
- 412
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- 11
I'm sure the good folks at HeadRoom will be happy to help me out with this but they're closed today and I'm in instant gratification mode so I figured I'd tap the limitless expertise of Head-Fi...
I've had the MOH(R) for over a week and am enjoying it a lot. However, last night when playing a CD requiring a higher than usual volume setting, I discovered that I was getting 60Hz hum when the ground lift switch is in the "Float" position which is recommended for "normal use". Switching it to "Off" pretty much cured the problem; hum is only detectable when the gain switch is on the high setting and the volume control is 3 o'clock or higher.
The HeadRoom manual indicates the switch be set to off only when the MOH is used as a preamp - and I ain't doing that. My setup is simple headphone amp - CDP into Input 1 and HD650s plugged into one of the jacks. CDP and amp are plugged into an Adcom line conditioner. I've used the identical setup for years with an old model HeadRoom Home and get no hum even when the volume is at full throttle (there's no ground lift switch).
Thoughts? Is the switch merely miswired? What are the other possibilities or for that matter, just what does a ground lift switch do?? Should there be any sonic differences depending on the setting?
Thanks much!
Beau
I've had the MOH(R) for over a week and am enjoying it a lot. However, last night when playing a CD requiring a higher than usual volume setting, I discovered that I was getting 60Hz hum when the ground lift switch is in the "Float" position which is recommended for "normal use". Switching it to "Off" pretty much cured the problem; hum is only detectable when the gain switch is on the high setting and the volume control is 3 o'clock or higher.
The HeadRoom manual indicates the switch be set to off only when the MOH is used as a preamp - and I ain't doing that. My setup is simple headphone amp - CDP into Input 1 and HD650s plugged into one of the jacks. CDP and amp are plugged into an Adcom line conditioner. I've used the identical setup for years with an old model HeadRoom Home and get no hum even when the volume is at full throttle (there's no ground lift switch).
Thoughts? Is the switch merely miswired? What are the other possibilities or for that matter, just what does a ground lift switch do?? Should there be any sonic differences depending on the setting?
Thanks much!
Beau
