rumble issues - see old thread update

Tom,

I was just pointed to this thread. There's too much good inforamtion to sift through at the moment, but based on the names of the posters, along with a quick scan, it looks as if you've received good advice.

I likely missed some of the finer points, but here are some thoughts.

1. Same problem with all sources?

Do you get the same pumping when playing CD? I assume this isn't the case, but it needs asking

2. Changes in stands/shelves.

This strategy seems to be pointing you in the right direction. No time to comment on the apparent disconnect of suspending an unsuspended turntable.

The key point to mention however is, that with Vibraplanes, microscope tables, etc., the entire 'table is suspended - the critical relationship between drive system and platter is still intact.

Maintaining this fixed relationship between drive system and platter/bearing is key to the success of an unsuspended design, and placing the entire assembly on an air table is consistent with the design goals.

My expereience of a Townsend Seismic Sink on my turntables was essentially a whole lot of trouble for no improvement over a *well* *implemented* sandbox design.

I've never met Sorbothene that I wanted in the same zip code as my hi-fi, but I can't profess to having tried every last permutation. Let's just say that it's the last place I'd look for answers.

3. Cartridge.

Don't rule out the cartridge, just because the Tri-Planar/Universe is a ubiquitous and compatible combination. You might have a sample that's aging differently. Mount another cartridge. You've tried enough differnt things to not want to overlook this.

4. Oil.

It wouldn't hurt to re-lube as you've been running your rig for something like 3-4 years. I don't expect any changes here.

I'll try to work through this rather long thread as time permits, but don't hesitate to call me.

Cheers,
Thom @ Galibier

The key point to mention however is, that with Vibraplanes, microscope tables, etc., the entire 'table is suspended - the critical relationship between drive system and platter is still intact.

Agreed, and we go even further. In our setup the entire table + system + rack are suspended as a single entity, well away from the table and drive system. All our sorbothane floor supports see is a single, rigid mass of nearly 400 lbs. This is very different from sticking it directly beneath the TT feet or something. I tried that once, just for ha-ha's, and it sucks big time.

Agree that the connections between drive system, platter, bearing, plinth, armboard, tonearm, cartridge, LP and record clamp must be as non-compliant as one's components allow. The only compliance anywhere in our vinyl setup is Stillpoints instead of spikes beneath the plinth. As anyone who's tried them knows, they do ennable a tiny degradation of transient speed and dynamics, though most feel the reduction in sound floor makes for a worthwhile tradeoff.

It's about thoughtful implementation, as always.

Hi Doug,

Thanks for the clarification on your Sorbothene implemenation, as well as the validation that locating it closer to the source component is a non-starter.

Cheers,
Thom @ Galibier

What I find bothersome about the MinusK, and I fully admit I have no experience with it, are the reports of these going into oscillation by something like a cd drawer opening and closing. It seems that they do dampen out and work, but I can't imagine my gear on top of something that moves when queuing a record. I suppose I'd have to see it, but it doesn't sound comforting. :-)

Finally resolve what was wrong

the feather test - moving a feather lightly against the cartridge parallel to the record should move  the headshell

If not the tonearm bearing isn't moving properly


The tonearm bearing wasn't moving suficiently so the cantilever was moving up and down causing all the pumping

had the bearing fixed