Posted by Todd R (A) on April 20, 2008 at 08:00:09
Hi, Hope you can help me with a problem? I have a stock VPI Scoutmaster with the standard JMW 9 arm. My cartridge is a Benz Micro M2 which weighs in at 8 grams, tracking at 1.9 grams. Phono stage is the Benz PP-1.
Problem is at the beginning of the record, I'm getting a lot of subsonic woofer pumping. This is on perfectly flat records of any weight or thickness. As the arm gets closer to the center of the record, the pumping gets to be less and less until by about 2/3rds in it's pretty much gone.
I took note of where the pump occurs, attached a small section of tape to the center of the record. I then rotated the record 90 degrees on the platter and checked it again. The pumping followed the the same spot on the record, so I don't think it's a problem with the platter.
Even though I was in the right resonance range for arm/cart matching, I tried adding the 4 gram headshell weight but that didn't help.
I tried a different belt and that didn't help.
I'm out of ideas, any clue what's causing this? Todd R
