Thoughts On Turntable Clamps And Weights

@mijostyn who's the app publisher? There's more than one fitting your description.

The one I got comes up as "Vibration Meter, seismograph": "Measure all vibrations" by ExaMobile S.A.

@dwette 

Go to yellowagents.com/seismometer

@mijostyn OK. I got that one, for a couple bucks.

If I put my iPhone on the platter and bang on the isolation platform I get tiny little blips (like small bubbles). If I bang on the rack the isolation platform sits on the tiny blips are even tinier. If I walk around there is is nothing.

As an experiment I also wedged the phone between the arm board, and the base of the tonearm, while playing the MMJ45 of Art Blakey and Jazz Messengers Mosaic. That should load the room with enough bass and dynamics. Without doing anything else the measurement is a solid straight line while the record plays: no blips at all. While I'm playing that I bang on the iosaltion platform and get tiny blips, and can kind of hear it in the bass. And banging on the rack the isolation platform sits on results in even tinier blips. No mistracking in any case.

I should try Weather Report Sweetnighter and turn it way up to see what happens.

Bottom line though is that while I'm playing a record it's not recording even the slightest vibrations that I can tell.

VPI tables have always come with a threaded (1/4-20) spindle and associated record clamp (and a 2mm thick x 1.25" diameter rubber washer to install under the LP).

Their first table (the HW-19) featured a platter that was a 1" thick slab of aluminum with a thin sheet of lead glued onto it’s underside, and covered in cork. The Mk.2/3/4 iterations of the HW-19 had a platter machined from black Delrin (often misidentified as Acrylic, even by VPI themselves), 1" thick on the Mk.2 and 3, 1.5" on the Mk.4.

All the VPI tables that have followed the HW-19 have (I believe) featured 1/4-20 threaded spindles and associated clamp, regardless of what material each table’s platter was made of.

The first VPI clamp was made entirely of Delrin, followed later by a stainless steel/Delrin combo for more money.

Black Diamond Racing---already well known for their carbon fiber shelves and "Tiptoe"-style cones---then introduced a carbon fiber record clamp with 1/4-20 threading, and it is really nice. Very dense and stiff, much more so than either VPI clamp. BDR made it in two iterations, a 1-pc and a 2-pc. Neither is still in production, but occasionally show up used for $100-$150. Well worth checking into if you like record clamps and have a spindle with 1/4-20 threading.

@dwette,

It is not all that bad but you have to remember, your cartridge is more sensitive than your phone. Ideally you should be able to tap around the turntable and jump up and down in front of it and see nothing but a straight line on the phone. Sweetnighter (one of my favorite Weather Report records) does not have very low bass in it. Play a Billy Cobham drum solo loud. Do you have subwoofers? Systems without subwoofers generally will not project much below 40 Hz. That is a full octave they are missing.