Turntable Rumble

[rocket-andy]

I bought a Pioneer turntable on eBay recently so I could listen to some old albums again. I have noticed, however, during some quiet passages, that I can hear some turntable rumble. I think my problem is twofold - one, this turntable was made back in the '70's and isn't that high-dollar of a turntable, so it probably does generate more rumble that a really good turntable would. Second, I am using a subwoofer, which probably reproduces that low rumble pretty well. It probably wasn't a problem back in the 70's, since subwoofers weren't used and most speakers probably didn't go that low, but it is a problem for me now. The question is: how can I minimize this? Is there a different mat that I should use instead of the hard rubber OEM turntable mat, or do I need some kind of isolators under the turntable feet, or what? Any suggestions would be appreciated.

[mas]

You are going to first want to make sure that the turntable is as isolated from mechanically transmited vibrations such as those coming from coupled surfaces on which the turntable sits, as well as transmitted energy such as low frequencies directly impinging on the turntable.

A mat may help a small amount, but your problem is more fundamental. You are not going to be able to diminish the fundamental mechanical noise of the turntable to any great extent. That is typical of the design and suspension.

This is why many preamps included a 15 and/or 30 Hz LF "rumble" filter, specifically for this purpose.

While you are discovering part of the romance of vinyl, you might also look up one of the Art Clean boxes specifically for the presence of the delightful capacitors they employ as protective devices for DC blocking. (I still get a kick out of the panic over this in the other threads, as if they cant simply jumper the caps if they are certain the units they are using will not pass DC and if they think they are really listening to material with lots of intentional info at 10-15 Hz!!! )

[Guest " "]

rocket-andy

let me translate what mas said....

him say...buy two of these....

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=266-246

if you have seperates, put it between your pre-amp and your amp.

If you have an intergreated with a pre-amp out and power amp in, put it there.

This will only allow frequencies above 20hz to get to your amp. There are other models such as a 30hz one, but I think 20hz will do it.

[oldenough]

I made the same isolation as Mark suggests, it works very well.

[Klipschfoot]

Oh, I thought this was a thread about two turntables squaring off.

[joessportster]

i also used a platform like mark suggests and it solved all issues with vibrations / rumble on what was my initial table set-up

Joe

[oldbuckster]

Isn't rumble just a fact of life with inexpensive turntables ? The better the cartridge, the more rumble you might hear. Sometimes I never heard it until I recorded something, then during playback the rumble was there ............ Idler wheel type always rumbled, Belt better, Direct Drive, most rumble free ....

[Mallette]

If isolation is the issue, a stack of cinder blocks is an easy, if less than elegant, way to isolate. If it works, a nice pedastal built or bought with a 100 lbs. or so of gravel is easier on the eyes.

Dave

[rocket-andy]

These look neat but I don't have separates, nor do I have a pre-amp out/power amp-in setup. I bet they probably wouldn't work if I plugged them into the "phono" inputs on my receiver, and then plugged the turntable into them, would they?

[rocket-andy]

I was talking above about what mas and speakerfritz suggested.

[Guest " "]

These look neat but I don't have separates, nor do I have a pre-amp out/power amp-in setup.  I bet they probably wouldn't work if I plugged them into the "phono" inputs on my receiver, and then plugged the turntable into them, would they?

They would not work correctly in line with your phono.

What model receiver or amp do you have.

[Clipped and Shorn]

I have used Mark's racquet ball isolation scheme several times now with phono turntables and CD players and it solved any and all problems due to foot falls as well as woofer feedback (and small earthquakes). Depending on the surface area needed for the TT or CD player, I have used (inexpensive or free) remnant cuts from a local marble cutter, selected slabs from a local rock and landscaping supplier, and even large square stepping stones from the local Orchard Supply (very inexpensive). The racquet balls are several to a can at the local sports shop. Not knowing, I did not glue the furniture cups down or to the slab (do not recall if that was suggested when I first read about this scheme a few years ago). I simply placed the furniture cups with the correct spacing on the table or shelf, placed the balls in the cups, then carefully positioned the slab on the balls. So far, no problem - have used this method a half dozen times. As long as you do not try to move or tip the whole table with this assembly resting on it, everything seem to stay put. The trick is getting the slab placed correctly (centered) on the four balls. Gluing the furniture cups to the slab does seem like a good technique both for stability (security) and for taking the guess work out of spacing and positioning. Eventually I might do the gluing, but at this point, probably not, since everything is set up and my time is more spent listening and enjoying. At least my vinyl shelving has been bolted to the walls and my house foundation is retrofitted.

-Clamped and Shored

[Clipped and Shorn]

I dug up another reference to this general isolation method (see below). Do you think it was a true audiophile who wrote it?

However, upon careful reading, it seems like "how not to do it", and it opens up a pandora's box of possible audiophile arguments as to what sounds better:

PS, I do not recommend that you slash your balls!

1. Blue balls.

2. Green balls.

3. Black balls.

4. Marble with slight marbelling.

5. Marble with medium marbelling.

6. Marble with lots of marbelling.

7. Slate (low, medium, or high thud factor)

8. Six balls versus four balls.

9. Number of knife slashes in balls. How evenly spaced. Which Xacto blade used, remember they come in different shapes, I suspect the pointy ones best for jazz, the wider ones for rock, etc.

10. Angle of knife slashes in balls in relation to slab or table.

11. Seamco #558 balls versus other models.

12. Clear furniture cups versus brown ones versus NOS vintage furniture cups.

13. Break-in period for furniture cups.

14. Break-in period for balls (varies with ball color or model etc.)

15. Break-in period for slab.

16. The sound resulting from honing, polishing, and/or facing the slab (well worth it?)

"The Shock Platform: An Easy Solution to Acoustic Feedback
The problem of acoustic feedback is far more generalized than most audiophiles recognize.
If the system does not actually "howl" when the gain is cranked up, many are confident that all
is right with the world. If only it were so. When even the subtlest amounts of acoustic feedback
are eliminated, the sonic results are startling.
Solutions to this problem have ranged from sheer mass (in the form of brick platforms) to
elaborate construction projects using springs or Barry mounts. Here is a project, courtesy of
Mel Schilling and Craig Goff of Music and Sound of California, that is incredibly effective soni-
cally, attractive, and easy to build.
A stonemason will provide the 16" x 20" x 3/4" slate slab required for the top. For the few
additional dollars, have the edges and face honed. The results are worth it. Ours cost $30 for
the stone and polishing.
It may be difficult to resist splurging on a piece of sexy marble, but as my wife (who
shopped for the parts for this project) can testify, marble resonates more than slate. In fact,
it actually rings. The greater the marbling, the more the ringing. The dull thud of slate is
definitely the way to go. Our piece weighed a hefty 28 pounds.
Your local sporting goods dealer will supply you with six black racquetballs. Use only the
black balls, as the blue and green types are not as highly pressurized, their walls not as thick
(for support). We used Seamco #558. A stop at the hardware store for six plastic caster cups,
and you are done. These are the cups that fit under furniture legs to prevent carpet wear. Get
the 1-3/4" size. We liked the clear plastic.
Now, with an X-acto knife, make five evenly spaced, bladewidth slashes across and at right
angles to the center seam of each racquetball. Drop a vented ball into each caster cup so that
the seam is parallel to the tabletop (and the slashes running perpendicular). Place the slate slab
on top of your new shock absorbers. With your turntable atop the slate, adjust each racquetball/
caster cup so that the weight is evenly distributed. You may find that you have to experiment a
bit for very light turntables and remove a ball/caster or two, or add an additional one for very
heavy tables.
What will you hear? If your system is like ours, with "no feedback problem", you should
hear greater clarity throughout the entire frequency range. Triangles have a purer ring; a
subtle raspiness that affected all instruments is now gone. Bass tightens up remarkably and
subjectively goes deeper. Break-up that sounded like mistracking or power amp clipping has
disappeared.
We must emphasize that we heard all of these effects on a system previously considered
immune to feedback, or at most, subject to minimal amounts. Needless to say, we now consider
the shock platform to be as necessary for the full realization of a system's capabilities as proper
speaker placement or phono cartridge alignment.
-- Robert & Beverly Wolov (Pennsylvania)

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

-Slabbed and Scored

[fini]

Blue balls might interfere with your enjoyment of the music.

[joshnich]

Another easy way to go is to use small innertubeslike those from the wheels of small trick bikes or for those of us who are a little older - like those on a sting ray. Perfect size. Inflate and they fit under a stepping stone and there is no danger of the stepping stone sliding off.

I saw this used in a local audio "salon" and the guy uses the slate stepping stone small bike innertube set up under his amps, cd players and tts. I imagine that it really only effects the tt. But at least he isnt selling some incredile high priced spikes!

Josh

[fini]

Good advice Josh, but you have to be careful your tonearm doesn't pop a wheelie.

[InnerTuber]

Warning - if you have a lab do not use tennis balls. It is a proven fact that lab vision reproduces tennis balls as ducks in need of fetching. In the unfortunate event your lab elects to fetch your balls, first, you will likely replace your now drool soaked turntable. The following is a field procedure I found should you need ball replacement. If turntable fails to operate or should it perform erratically, it may need a ball replacement. Because of the delicate nature of this procedure, replacement of balls should only be attempted by properly trained personnel. Before proceeding, determine the type of balls by examining the underside of the mount. Domestic balls will be larger and harder than foreign balls. Ball removal procedures differ depending upon manufacturer of the cups. Foreign balls can be replaced using the pop-off method. Domestic balls are replaced using the twist-off method. Balls are not usually static sensitive. However, excessive handling can result in sudden discharge. Upon completion of ball replacement, the turntable may be used immediately. It is recommended that each replacer have a pair of spare balls for maintaining optimum satisfaction, and that any listener missing his balls should suspect local personnel (see warning above) of removing these necessary items.Hope that helps …

[artto]

Is the turntable belt drive or direct drive?

Direct drive turntables are notorious for low frequency rumble. Their so-called "specs" were almost always "weighted" so that we, the unwarying consumer, who usually doesn't know any better, thinks it has better "specs", when in actual practice the things sucked. I had a beautiful Luxman direct drive turntable at one time, built like a Rolls Royce. Unfortunately it didn't perform like one.

Some other food for thought. The suggestion Mark Deneen put forth is a good one. There is however another school of thought, something you might try. A long time ago I had my turntable racks wieghted down with more than 300 LBS of concrete blocks of various sizes. I also had several of these underneath the turntable itself. I was informed by Linn Products after they saw my system/room in a magazine that I shouldn't have so much mass under the turntable (Linn LP12). They said it was better to have the table on a light shelf, preferrably one that is phyically decoupled from both the turntable and rack/shelf structure. It worked for me & I haven't looked back since. It freed up a lot of rack space too!

[Clipped and Shorn]

In our labratory we have substituted frisbees for balls and are currently gathering data.

-c&s

[scott0527]

They said it was better to have the table on a light shelf, preferrably one that is phyically decoupled from both the turntable and rack/shelf structure. It worked for me & I haven't looked back since. It freed up a lot of rack space too!

Can you describe that in more detail? I'm a bit confused by your description. I too had been told that Linn's in particular, sound best on a light shelf or table. The best my LP12 ever sounded was when I placed it on a cheap, light weight Ikea ,"Lack" as it was called, end table. My room was forced to change a bit but I've been trying to get back to the light weight table for my LP12.