ADA Depot - A Forum To Support Users of ADA Amplification Gear
Let's Get Technical => All PREAMP Tech Tips & Support => Topic started by: revhed666 on April 02, 2014, 07:43:54 AM
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you guys solved one problem for me heres hoping you can help with this one too. turned on the rig today and MP-1 has developed a massive hum. i run it in stereo with a JMP-1 and the noise from both were comparable, but today the MP-1 is blasting through the gate. the JMP-1 is still as it was. the hum is constant. inserting ground loop killers into the chain at various points had no effect, nor did removing the MP-1 from the rack and running straight to power amp, again with ground loop killers. it is definitely a problem in the MP-1. any ideas guys? im reluctant to drop cash on mods if its just going to keep having problems but i really dig the sound im getting right now. i have a couple of other rack preamp modellers/FX and the MP-1/JMP-1 combo beats them hands down. cheers in advance
edit: also changed preamp tubes with no difference
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Do you get hum on all 3 voicing (SS,tube clean and tube dist.)?
Does the hum go up and down with
1)master volume settings (not the front pot)
2)OD1 settings
3)OD2 settings
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gday MJMP thanks for your help again. hum is present in all 3 channels and goes up and down with each gain setting. the hum is less on the lower gain channels but seems relative to the gain level of the channel and the amount of gain used.