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Leslie 122A has hum fields
Old 4 weeks ago
  #1
Gear Addict
 
spectrasound's Avatar
 
🎧 10 years
Leslie 122A has hum fields

I bought a Hammond C3 organ with a very new Leslie 122A. When stereo mixing the cabinet the right side mic always exhibits hum...which never appeared on the older Leslie 122. The only difference I see is they no longer have 4 motors (hi & low speed for top rotors and hi & low speed for bottom rotor. They now use a solid state PCB which feeds variable pulse width square wave AC to the top & bottom motors. My workaround was to remove that top & bottom back panels and mic it from the rear, but we get engineers in here that want to put mics on the sides. I can't be the only one experiencing this. Any suggestions for mods or shielding (mu metal?). Thanks in advance!
Old 4 weeks ago
  #2
Lives for gear
 
jaddie's Avatar
 
🎧 10 years
Quote:
Originally Posted by spectrasound ➡️
I bought a Hammond C3 organ with a very new Leslie 122A. When stereo mixing the cabinet the right side mic always exhibits hum...which never appeared on the older Leslie 122. The only difference I see is they no longer have 4 motors (hi & low speed for top rotors and hi & low speed for bottom rotor. They now use a solid state PCB which feeds variable pulse width square wave AC to the top & bottom motors. My workaround was to remove that top & bottom back panels and mic it from the rear, but we get engineers in here that want to put mics on the sides. I can't be the only one experiencing this. Any suggestions for mods or shielding (mu metal?). Thanks in advance!
Are you using a dynamic mic? They are quite susceptible to hum fields. A condenser might help.
Old 4 weeks ago | Show parent
  #3
Gear Addict
 
spectrasound's Avatar
 
🎧 10 years
Quote:
Originally Posted by jaddie ➡️
Are you using a dynamic mic? They are quite susceptible to hum fields. A condenser might help.
I'll try a pair of SDC transformer less mic.s
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