rumble issues - see old thread update


I originally posted this under amps
as I thought I might be experiencing clipping

looks like it's definitely turntable related and rumble from subtle record warpage is the main culprit

see my last comment on this thread

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1273520086

may check out with my outboard ZYX Artisian phono pre when I get it back from a friend

Tom
128x128audiotomb
Oops! Dogma demolition time!

"Adding a suspension beneath a non-suspended table" is exactly what devices like the Minus K do. Chris Brady and others have found that it provides major benefits beneath even the heaviest (unsuspended) tables and is markedly superior to the best 300+ lb. unsuspended stands. My poor man's equivalent (sorbothane hemispheres between our equipment rack and the floor) also add a suspension to a suspended table.

Yes, our Teres is ultimately sitting on a compliant suspension. So was your Galibier both times you brought it down. I trust you didn't hear any softening of dynamic impacts, murky bass or other effects attributed to lightly suspended tables. The trick is to do the suspending effectively, with awareness of certain unavoidable contradictions.

A. The main reason to suspend a TT is to isolate it from floorborne vibrations.
B. The main reason NOT to suspend a TT is to allow the table's mass to resist being displaced by big transients.

These goals are self contradictory, so we address each while trying to minimize impacts on the other.

In our setup the non-moving mass of an 80 lb. TT is pretty tightly coupled to the ~300 lb. mass of our equipment rack and other gear. Except for the tiny amount of movement allowed by the Stillpoints (which do slightly diminish dynamics, as you know), we effectively have a ~380 lb. plinth to resist transient-induced displacements. So far, so good.

To avoid floorborne vibrations, this entire mass is sitting on weight-specific compliant bits to create a tuned system. The compliant layer sees all ~380 lbs. as a single mass and has a resonance frequency of < 10 Hz. If I could afford a Minus-K large enough to suspend the entire rack I could get that down to around 2 Hz.

To get a ghostly low sound floor and big dynamics too, we must suspend, but not too much. The devil's in the details.
I also have a Galibier (Stelvio) table and have had a friend's ZYX mounted on my Triplanar. We did not experience the woofer pumping you are experiencing. Your CRAZ rack is an amazing product. I wonder if it would be worth a call to Kevin; perhaps he could point you in the right direction. As an aside, my turntable sits on a GPA Monaco platform on a EquaRack. Perhaps the EquaRack product might be worth exploring.

BTW, great information on this thread.
Nope, no dogma here. I specifically included this is my opinion.

The granite was added on top of the craz, if I read Tom's post correctly. If that extra mass reduced oscillations getting to the speakers, something is moving too much. I didn't mean to point directly at the Craz, just whatever the table is sited on. But if that is the Craz, well not everything works in every application.

The Stillpoints are the limit I will go with compliance under my Gavia, and even then I know it is a compromise to the sound I could get with a braced, aluminum shelf on my sandbox. If I ever grow tired of that beautiful Dakota Mahogany granite it will be gone along with the Stillpoints. Remember, I'm coupled to a concrete sub-floor so I don't have the issues of a suspended floor. If I did I might own something other than what I now own. Suspend away if you want or need to. I don't find it necessary or desirable under my table to get a low enough noise floor.

Yes, there are things I hear in the mid and upper ranges differently in your system and mine. But down low is a different issue, and that's what where talking about here. I dont hear any down low in your system, I never have. I have to extrapolate what I think it would sound like. But I realize you do have your system tuned for a different sound than I based on our different preferences. Even as close as our systems are, they are still as different as the music we each prefer.
Agree about the Stillpoints, we both heard similar advantages/disadvantages. Like you, I'd rather not have that compliance so close to the TT. I'd ditch them too if our Salamander rack weren't so ringy (it's like your Dakota Mahogany granite, except for the good looking part!).

That's different from the sort of suspension I was referring to though. We both know people with sub-20Hz systems, very high mass tables (200+ lbs.) and concrete floors. Every one who replaced a big, high mass stand with a Minus K reported significant benefits with no loss at the bottom end. We're not talking bouncy, bouncy Linn here.

Agree there's little down low in our system vs. yours. Our speakers roll off below ~42 Hz. They can't reproduce the bottom octave no matter what we do at the source.

FWIW, our missing low end is not by choice and has little do with sonic or musical preferences. It's a function of geography and budget: we lack room for a sub and funds for full range speakers that would fit.

I'd love to try big Coincidents, which claim 20Hz without being much larger than our B&Ws. They're also easier to drive, have great crossovers and drivers (on paper anyway) and they're not ported - no woofer pumping!

That's my segue back to the topic. Sorry to Tom for threadjacking!
I just finished reading up on that device. Oh, yeah. That MinusK is a completely different league. It had better be for that price. Then again, when you look at the price of decent equipment racks it doesn't look as expensive.