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I have been dealing with some rumble issues with my turntable, which is sitting on a wall-mounted shelf made of pine. I realize I need to isolate the turntable from the shelf, and am thinking of trying superballs...I suspect that will work with the problem I'm having.However, I'm also in the process of gathing materials to build a Ladegaard tonearm, which, because of the low height of the platter on my deck, can't be mounted right on the turntable. My question is this; if I add levelling feet to the tonearm base and the turntable, set them on something and then put the superballs under that something, what should the something be? MDF? Plexiglass? Slate? I've done searches here and can find pros and cons on just about anything, but I'm wondering if the particulars of this setup would suggest one material over another.
Follow Ups:
Hello there: I am the lucky owner of a Acoustic Signature Final Tool turntable and this is what I put under it: first of all I have it placed on top of the Billybags 2300 rack wich is strong and sturdy and has it's four legs ending with 4 spikes and cones; now, the whole rack is resting on a thick wood plattform to isolate it from the floor. On the top shelf of the rack I have a set of Harmonic Resolution couplers then a set of Harmonic Resolution damping discs, then a set of Walker Audio Super Tune Kit and then the turntable. I also have a double mat: the Sorbogel and then the original felt mat which came with the turntable. With all those items combined I control the vibration from the floor a lot (I live in a wood suspended floor apartment). Hope it helps, best, Antonio Machado.
And would work well for the purpose. With a turntable its recomended a platform exist between your shelf and the feet of the table. I use a pizza stone for this purpose.
Different TT designs work best with different isolation techniques.
Henry
Sorry...it's a Technics SL-1800, so it's not suspended or anything like that.
Hmmm. Well, placing Sorbothane hemisphere's under my Denon DD so that the feet were raised up off the TT shelf made a positive difference sonically for me. Not something one would do with a Rega or a suspended subchasis table, I guess, but it does seem to help DD tables. Might work for you. KAB has the hemis for $29 for a set of 4. I only used 3.
Henry
Turntable rumble is inherent in the turntable.
Did you mean feedback?
Maybe I'm not calling it the right thing...I've posted about this before, but I have a window air conditioner about six feet from the turntable mounted on the same wall - there's no way around this where I have my stuff. Normally it's fine, but when the AC unit kicks in it vibrates slightly, which winds up in the turntable. If I record an LP, for instance, and flip on the unit in between cuts, you can clearly see where it happens in the waveform, and it's not a hum or anything like that. I'm hoping the superballs will fix this.
get a thick plywood board larger than the TT by at least 4 inches in each direction (1" baltic birch if available or double up two 3/4") and hang on 4 chains from the ceiling, just make sure you anchor into joists. hang the chains at slight outward angle in all directions (joists should be 12" on center so say 24 or 36 inches apart at the ceiling) to advoid swinging. if you get J-hooks you can adjust the chains with a nut till level by drilling 4 holes at the corners of the board. depending on TT mass you might want to add some mass under the TT to add stablity but this should isolate the TT from almost anything but direct contact and insane DB sound levels. i have not tryed this myself but can not see why it would not work wonderfully, used to see it used back in the 70s. If propery anchored into joists near walls (i would go out a foot from the wall), should support 200 lbs. easily.
but why do't you try isolating the air con unit from the wall as well ? With rubber grommets & silicone etc, or even isolating the motor unit itself ? It must be bloted to something - put something rubber on the mounting points so less is transmitted to the case & the wall.
That would help at the root of the problem, making any TT support treatment more effective. + it's maybe cheaper to start there than with the TT.
This might be the solution, actually...the AC unit is just sitting in the window, no bolts or anything...I'm on the third floor, so there's no real security problem that way.
depending on how old the ac unit is, you might be able to remove the actual unit from the shell and tightly bolt the shell to the window and then reinsert the unit.just be careful the fins on those things are really sharp and will make mince meat out of your hands.
you might try mounting the A/C in a more rigid manner.
Ok.
Can your shelf support a mass-loaded turntable base? I have a DIY methos that may work for you....
I would assume; it's one piece of pine screwed into the studs and then the shelf is connected to that with large triangular brackets. I don't know that I'd trust it with a HUGE amount of wieght, but it can probably handle more than it has on it.
I'd work on the basis that the current set of brackets and shelf have to go...What you need to do is replace the existing brackets with a new set designed to hold a substantial load. The next aspect relates to how you mount the brackets onto the wall - the method, if not a brick wall (as it sounds like a wooden wall), would be to use mounting bolts that go right through and then use large diameter, thick steel washers to spread the load.
Once the brackets are installed, and before mounting the replacement shelf, mount some sorbothane (or equivalent) "bushes" on the top surfaces of the brackets and aligned with the mounting holes (light adhesive to hold them in place).
For a shelf, I'd go with a three-part "laminate" - the lower layer, a 25mm shelf made of MDF/Medite, which is drilled to match the holes in the brackets. Each drilled hole should also have a countersunk cavity bored on the top. Using countersink bolts, bolt the MDF shelf to the brackets, with nuts attached from below.
The upper layer shelf (layer 3) should be the same size as the lower, and should be another 25mm shelf of MDF/Medite.
Take a rubber bath/car mat and cut to the same size as the shelves and place on top of the lower shelf, before loosely placing and aligning the top shelf with the lower - forming layer 2 as the ham in the sandwich.
What you wind up with is a three layer "sandwich" - two layers of 25mm MDF, separated by a 3-4mm layer of rubber - and isolated (by the sorbothane) from the brackets, which are in turn mounted on the wall.
The additional rubber layer does two things:
1. Being rubber, stops the top shelf from sliding around
2. Acts as a second "isolation layer" to back-up the sorbothaneHaving no rigid connection between the two MDF layers limits the energy transfer to what can get through the rubber layer.
I don't know what the material costs would be in the USA, but could do that here in South Africa for around the equivalent of $35.00 - including brackets, mounting bolts, MDF, bath mat and sorbothane bushes..
Whew! Thanks for the in depth response...and I thought I was going to get away with superballs...let me let this sink in.
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