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So Weird- No Stylus Contact Woofer Pumping with Hana ML and Elac PPA-2

I observed the weirdest thing I have ever seen in audio. With the cartridge positioned above the record, tone arm locked up and platter spinning, the woofers were pumping on my system. I googled every permutation of query I could think of but came back with no hits. That’s when I decided to video the problem- link below:

Mystery Woofer Pumping

I could type out all the details but the video pretty much covers everything. I thought ya’ll might be interested in this.

 

mitchellcp
mitchellcp OP
86 posts
 

It’s static. I converted back to balanced operation and wet cleaned a few LP’s. Problem gone. I have an Ionizing fan on order and we’ll see how that works.

mitchellcp OP
86 posts
 

I think the reason the rumble filter doesn’t stop it is that it’s DC with a slow rise time. The o-scope looks hilarious.

noromance's avatar
noromance
9,898 posts
 

Kudos to @dadawada 

lewm
13,228 posts
 

DC has no "rise time", by definition. 

mitchellcp OP
86 posts
 

Which definition? What do you call the period of time in which a DC signal increases in amplitude, repeatedly and predictably, after which it decreases in amplitude repeatedly and predictably? 
 

 

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