isolation issues...?

Look, my wall mounted table with ball bearing isolation (search Barry Diamont in the forum) will also transmit taps to the base through the speakers. From my listening tests, that's not important. What IS important is if low frequency vibration from the speakers OR MOTOR is finding its way back to the needle. How do you test for that?

Put a record on the turntable. Disengage the belt from the motor or platter. Lower the arm and carefully place the needle onto a part of the record. Turn on your amp and preamp. Set to phono. Start turntable motor. Now increase volume. Any vibration from the motor making its way to the needle will be clearly picked up. You should just here silence if it's well isolated .

Now connect the belt back up but don't run the table. Place the needle back in a groove and turn up the volume. Poorly isolated tables will produce a feedback loop generated by low frequency feedback reaching the needle. Be careful here and be ready to turn the volume down quickly so as not to blow a speaker. If you can increase volume without the subsonic nasties creating this feedback loop, your table is properly isolated.

That's the stuff you want to keep from reaching the needle. Sure, it's nice to whack away at the base and hear nothing from the speakers, but it's the airborne vibrations that affect the sound.

 

Nice rig!

 

Tapping is probably not a good test unless your TT is suspended from springs. The pucks will probably isolate more sideways rather than up and down, the spikes I doubt will isolate much. On top of that the Isopucks are rated at 9kg each the TT alone is 20 plus everything else, I did try them with my TT and I get much better isolation with the big Orea Bordeaux.

You had before other problems with the TT, it might not be such a bad idea to try a shelf attached to the wall instead of having the TT so high on a rack. Unless you are suffering any actual problem looking for one is not going to make things easier on you. I think having the pucks on the columns is not a good idea either.

It's a beautiful system, enjoy it.

 

That is a sweet looking rig! When I experimented with turntable isolation, I found $32 nobsound bought from Amazon springs underneath a thick butcher block to be the most effective. I did put Herbie's thickest grungebuster in between both sides of the spring for extra measure as well as for leveling the uneven butcher block since I had a sheet of it lying around and it now passes the tap test.

I'm not saying that Herbie's grungebusters are better than isoacoustics but in my application, combined with nobsound springs it worked.

 

Lst time I had similar issue it was microphonic tube.. so as @Agitater said it quite possible coming from component and not TT

 

I agree, it did for me too. Talk about DIY.

 

Thanks for the feedback @Uglyversal

I went with these IsoAcoustic pucks as I didn't want to spend that much more especially as they are simply going to support a shelf and not component. Each pick supports up to 20 lbs so between the four of them, that would be a total of 80 lbs which is more than plenty to support the turntable and other associated items on top.

I don't want to entertain a wall shelf as I don't have the support necessary on the wall to be able to make that happen - I would rather persevere with the current setup and I am going to reach out to Peter over at Symposium to see if he has any other ideas - I will also see if Herbie has any ideas thoughts on this too. I don't want to have to replace the Symposium shelf but it may come down to that which is kind of ironic, as I had a nice 2" MapleShade butcher block at one point that I replaced with the Segue Iso, which may be a better solution for me at this time...You live and learn!

 

Thanks @Sam

Tried both tests as recommended above and no cone pumping that I could tell even at very high volume levels - unless I tapped on the shelves or the rack itself. Otherwise, no cone movement either with the motor running or with just the stylus sitting on the LP groove with no movement of platter.

Cheers,
Vin.

 

I don't have an easy answer for you and think some of the comments above, including @Agitater 's observations, point to the potential problems you are having: height, connection of the shelf directly to the legs of the stand (which is nice looking) and the complication of using both coupling and decoupling devices in combination. The cones aren't decoupling, as you probably know, and I've never found them good for isolation (I still have a couple sets of the old Goldmund cones which had damping material inside the cone- they were cool, expensive and didn't achieve much).
I had a different issue: footfalls in an old wooden house that would not be eliminated by a wall shelf partly b/c the turntable alone was quite massive - around 175 lbs or more, and add 50lbs+ for plinth.
A big MinusK solved that, but at a price and some argue that the MinusK contributes a sound of its own. I've never tried the active isolation systems using sensors which are quite expensive and from what I gather aren't really meant to isolate from very low frequency impacts, like footfalls.
From the looks of it, your combining all these different devices is both coupling and decoupling. The coupling isn't isolation. The decoupling-- how effective is any one of the devices, without the others? Choosing one that is the able to decouple the most may be better than combining them, particularly with cones.
What does VPI recommend? You have a concrete floor, their sand filled stand and their turntable. Harry must have some insight into how the system he designed works best- I'd tap him on the shoulder if you haven't already, if not for a ready made solution than some insight into what he thinks about his own designs.
Mass loading can work, but you are talking about a lot of mass, at a lower height, i.e., putting the mass into the rack, rather than up near the turntable. And, ultimately, if you tap a shelf that is connected to the turntable by a cone, it wouldn't surprise me that you hear that through the system. What are the pucks beneath the cones on the bottom of your turntable? Are those gel or solid?
Maybe something like the Townshend pod spring things with controlled release would work without all the other stuff, but I'd make sure you could return them if they don't work.
The only other thing I'd add (which may not be helpful but I think should be said) is that in the quest for isolation, you are changing the sound of your system; whether that is for the better is a different question than whether you've achieved some measure of isolation.
Not easy stuff and based on my experience, not always predictable by the theory, leaving aside the claims made by various manufacturers.

 

Put some hockey pucks under the turntable's feet, that may not stop it completely, but it will reduce it by lots. $10 will buy 4 nice pucks. I use them everywhere, even under my electronics.

 

I have issues with footfall in my apartment. It's not ideal asking my partner, who is a professional dancer, to tip toe as she walks past the turntable, and absolutely no dancing to the music near the turntable. I've spent a lot of time trying to solve this issue. Any rack that touches the floor will be a problem in this 80 year old NYC apartment building.
However, I've recently thought about using a load bearing structural wall that is made of brick and mortar to mount a rack to. The wall is about 8 inches thick and is rock solid.
Flipping through the Thomas and Betts catalogue, I can't help but see countless ways to attach their 1.5" Kindorf strut to the wall, and use one of their many different support brackets to hold up a wooden butcher block shelf. The great thing about this modular system is the extremely large amount of customization that can be done, and done rapidly using nothing more than a 9/16" socket and a torpedo level. By anchoring two pieces of the 1.5" kindorf to the wall using 3/8 double expansion anchors, I could move the rack up and down without drilling any additional holes later on. There are hundreds of ways to use the materials in the catalogue to build a foundation for any kind of rack one could conjure up.
Anyways, I haven't executed this idea yet, but it's something that I've recently been designing and plan to do within the next couple of weeks. I'm just trying to decide how I will finish it so that it doesn't look too industrial. Whether that means painting it, or wrapping the framing with wood to hide it.
Just thought I'd share my idea with my fellow Hoffman forum members.