View Full Version : Turntable noise floor tweaks?


jimreeves
10-28-2009, 09:37 AM
I'd like to see if you smart fellas here have any good ideas for how I might improve the S/N performance of my old Luxman PD-277 turntable.

It plays beautifully and the arm seems to bring out the best from my Denon DL-160 cartridge, but it obviously picks up more surface noise than my Pioneer PL-707. It should, considering it was originally rated >60db vs >80db for the PL-707 and is probably 10 years older. I'm not talking pops and clicks, just low level groove noise.

So are there any tweaks for this issue, or is it hopeless?

Damp the arm?

Isolate the motor?

Isolate the tranny?

Balifly
10-28-2009, 03:44 PM
Have you try using the turntable without the dust cover ?

jimreeves
10-28-2009, 03:49 PM
Yes, I always use it without the dustcover. It's really very enjoyable as is, just wish I could get a little lower surface noise out of it.

Balifly
10-28-2009, 03:58 PM
Isolate the tranny?

Any ideas on how to do that ?

Would dampening the platter help?

JohnVF
10-28-2009, 04:14 PM
Is there any place under the plinth to put some Dynamat? That also looks to have a pretty light arm, is the DL-160 a good match? Just curious, thinking out loud here.

Balifly
10-28-2009, 04:22 PM
There are some cavities or indentations in turntable platters, under the mat.
What do you think about putting some type of insulation foam or gel into the metal platter cavities?

Brett a
10-28-2009, 04:38 PM
Make sure the main bearing is clean and properly lubed.

Dynamat is a good suggestion, but can be overdone, killing the sound of a TT. I'd look at putting it between the source of vibration and the pickup, for instance under the platter between the spindle bearing and the rest of the LP.

I'm not familiar with your particular table, but I also surrounded the motor on my Rega with it as well as the tonearm mount, figuring these were sources and destinations for vibration.

Here's my thread on Dynamat and my Rega:
http://www.audiokarma.org/forums/showthread.php?t=228361


A sandbox with a lightweight load panel can drain away some vibration.

Here's my post on that:
http://www.audiokarma.org/forums/showpost.php?p=2396080&postcount=35

Keep us posted. (with pics preferably!)

jimreeves
10-29-2009, 07:38 AM
Thanks for the suggestions guys! I snapped some quick pics of the PD-277, it's unsprung wood plinth with a stainless steel top plate. The direct drive motor and the tonearm are hard-mounted to the plinth. I added some rubber gromets to the transformer which was also hard-mounted but haven't noticed a difference. I could isolate it further by extending the wires and removing it from the plinth altogether.
I just put my spare Ortofon OM-20 on to see how it sounds but haven't had time to try it yet.
It has a heavy aluminum platter which could be damped underneath with some sort of spray on damping material though it doesn't ring with the mat in place. I could try to soft mount the motor/platter but I'm not sure how I'd go about it.
I suspect I'm getting a bit of resonance from the arm with the DL160 cart, I'll know better once I've tried the OM20.
The adjustable feet are hard-mounted to the bottom 1/2" mdf base board and the feet aren't very flexible. They're plastic outers with a rubber insert that has a threaded steel stud and felt bottoms, no springs.

eteller
10-29-2009, 12:28 PM
I packed about 5 lbs of modeling clay in the plinth of my Technics SL-D3's nooks and crannies, sprayed the bottom of the platter with truck bed liner, it no longer 'rings'.

Brett a
10-30-2009, 04:31 AM
.


That big metal plate that the main bearing is mounted through would be my first target. Try damping that. I bet you'd hear a difference.


http://www.audiokarma.org/forums/attachment.php?attachmentid=176553&d=1256818804

Although no one has mentioned the cost of it in this thread so far, I have heard people complian about the cost of Dynamat. I was a bit hesitant to spend $25 on two 12" sheets. But in retrospect, I'm glad I did. You may only use one sheet on the 'table. Looking at it that way, it's a pretty cheap tweak.

This just in!
Amazon is selling these $25 packs for $10 right now.
http://www.amazon.com/Dynamat-10415-Xtreme-Speaker-Sheets/dp/B00020CATC/ref=sr_1_7?ie=UTF8&s=automotive&qid=1256895199&sr=8-7

...

eteller
10-30-2009, 06:38 AM
Dynamat is pretty much like Monster Cable, you're paying for marketing. Checkout ebay for Fat Mat,etc. I did a whole car for about $75 that way.

jimreeves
10-30-2009, 03:29 PM
I don't have any Dynamat, is it a semi-flexible sheet? Not sure how I would attach that to the bottom of the platter. I do have a 12"x12", 1/8" thick sheet of sorbothane I was thinking of using as a sandwich between the motor and the plinth. The modeling clay and bed liner spray sounds interesting.

The main bearing is sealed and has no means to be lubed according to the service manual.

Has anyone found a good product for tonearm damping?

I'd also like to upgrade the feet in some fashion but haven't figured what to use yet.

Tedrick
10-30-2009, 03:41 PM
Try an aftermarket TT mat. The Way Excellent II mat from Herbie's Audio Labs is not expensive and very effective at damping the platter, tightening up the bass, and cleaning up the treble.

Brett a
10-31-2009, 05:39 AM
I don't have any Dynamat, is it a semi-flexible sheet? Not sure how I would attach that to the bottom of the platter.
Dynamat looks and feels like a sheet of tar. The newer varieties have a layer of aluminum on one side and the the other open side is adhesive. You stick it on what you want to dampen and then press or roll it firmly onto the surface.

The difference between Dynamat and say, sorbothane, is that Dynamat is made to deaden the resonant vibration of the object it's stuck to, whereas sorbothane is great at absorbing energy that passes from one side of it to the other.

Sounds like sorbothane would be worth a try between your motor and plinth. Keep in mind how it might change any alignments though.
I do have a 12"x12", 1/8" thick sheet of sorbothane I was thinking of using as a sandwich between the motor and the plinth.