Lew, there doesn't appear to be much interest in logic here. ;-)
Matt posted earlier that his woofer pumping:
1. occurs with his new rig but not his old one.
This earmarks the new rig as specifically involved with the problem.
2. occurs on all records.
This eliminates "the records we play" as a culprit and points toward the (new) equipment.
3. occurs in the specific, repeating pattern of 4 pumps and a pause.
This eliminates both tonearm/cartridge interactions and "the records we play" as culprits, since either one would generate pumps in an irregular pattern based on the individual record.
4. occurs faster when playing at 45rpm than at 33rpm.
This suggests a defect in the TT drive system or bearing. No other elements in the vinyl playback chain are speed dependent.
Taking #s 3 and 4 together, the most likely suspects are a defective bearing, motor or belt. Any of these could cause "bumps" in a regular, repeating pattern that is speed dependent .
I pointed this out on 7/21. Jperry, Rodman99999, you and now Atmasphere have all reached similar conclusions. We've advised Matt on diagnostics and that he should consider filing a warranty claim on the new TT.
Aside from non-sequitars like schlepping granite, his only response was that the TT is new, so why would he need to file a warranty claim? This was irrational, so...
[insert .gif of dead horse being cruelly if amusingly beaten... 4 beats and a pause, 4 beats and a pause...]
