[hciman77]

Before I give up on Vinyl I want to see if I can do something to isolate my TT. At present I have my turntable sitting on a fairly solid but non-decoupled wooden table with tubular metal legs, the option for a separate floor-based stand/table such as my old Sound Organization Table or specialist rack or shelf does not exist at present and is not likely to in the near future.

With that as a given , despite its supposed low noise figures I am getting a lot of regular low frequency noise , I take this to be either rumble (which would be annoying as both TTs have low rumble figures -78db) or some form of acoustic feedback, I listen on headphones so it isnt from speakers. It is the same on both turntables.

I was looking at some spikes that could be fitted to the base of the TT, would these help at all ? or is there some other way of reducing this noise feeding back with my present set up, cheaply ? would a heavy slab of something help ?

EDIT: Would Sorbothane half balls work ?

 

[Herandu]

Have you tried a drop of TT oil in the center spindle?
See this article:
http://www.audioorigami.co.uk/MainBe...structions.pdf
You can also get the oil on that site. I initially thought it to be just another bit of snake oil, but I tried a few drops after a friend of mine bought a bottle. The oil really dampens the rumble noise after I used some of it. So I now got a bottle of my own. And you get a money back guarantee!!!!

 

[jwilldermood]

A target or apollo wall shelf is a very good solution for around 100 bucks. Even cheaper is to cut some handballs in half and put them under your TT, sorbothane would work better. Also check the tracking weight of your cart and adjust it.

 

[hciman77]

Quote:

Originally Posted by Herandu /img/forum/go_quote.gif Have you tried a drop of TT oil in the center spindle? See this article: http://www.audioorigami.co.uk/MainBe...structions.pdf You can also get the oil on that site. I initially thought it to be just another bit of snake oil, but I tried a few drops after a friend of mine bought a bottle. The oil really dampens the rumble noise after I used some of it. So I now got a bottle of my own. And you get a money back guarantee!!!!

Ha, now I remember, sewing machine oil - that always used to be the answer, I have duly ordered some from Amazon - thanks for reminding me.

 

[hciman77]

Quote:

Originally Posted by jwilldermood /img/forum/go_quote.gif A target or apollo wall shelf is a very good solution for around 100 bucks. Even cheaper is to cut some handballs in half and put them under your TT, sorbothane would work better. Also check the tracking weight of your cart and adjust it.

I have ordered some Sorbothane Hemispheres. The tracking weights are correct to the best of my judgment, I spent a while carefully balancing the arms and aligning the cartridges.

 

[Herandu]

Quote:

Originally Posted by hciman77 /img/forum/go_quote.gif Ha, now I remember, sewing machine oil - that always used to be the answer, I have duly ordered some from Amazon - thanks for reminding me.

I actually used to use that stuff when I 1st got into turntables. Don't forget the lint free cotton buds and some pure alcohol to clean up any previous grease etc. The only problem I find with the sewing machine oil is that it is too thin. I find turntables need a heavier viscosity.

 

[hciman77]

Quote:

Originally Posted by Herandu /img/forum/go_quote.gif I actually used to use that stuff when I 1st got into turntables. Don't forget the lint free cotton buds and some pure alcohol to clean up any previous grease etc. The only problem I find with the sewing machine oil is that it is too thin. I find turntables need a heavier viscosity.

Well I just ordered a cleaning kit as well so I will see what the effect of cleaning, isolating and lubeing is. I had forgotten what a fiddly business Vinyl was , hmm maybe this was one of the reasons I went digital in 1984 after all

 

[derekbmn]

SAE 30 oil seems to work the best for me . Run down to the local gas station and see if they have some.

 

[JadeEast]

Also many people rave about
http://www.tufoil.com/

Most budget isolation I think I had good success with
was bags of sand zipp-locked and taped shut with
a piece of wood on top. Without stuffing the bags
totally full I was able to get the board absolutely level
with just a bit of tweaking.

 

[memepool]

Quote:

Originally Posted by hciman77 /img/forum/go_quote.gif Well I just ordered a cleaning kit as well so I will see what the effect of cleaning, isolating and lubeing is. I had forgotten what a fiddly business Vinyl was , hmm maybe this was one of the reasons I went digital in 1984 after all

These are direct drives though so I would proceed carefully as regards lubing. Did you get a manual? Have you tried contacting Denon as they are still selling pretty decent new direct drives and should be able to advise on lubricants as I doubt they've changed their motor design since the 80s.

I think you hit the nail on the head with acoustic feedback. Remember DDs are designed around the principle of high mass supports so really they need to be on a solid plinth or concrete floor. The cheaper ones with plastic composite plinths like you have even more so.

If you can't do this then layers of dense material like marble or granite (chopping boards) with foculpods in between will help.

Also removing the lid whilst playing will help.

If you absolutely need to site it on a table then a suspended subchassis design is much more suited.

 

[hciman77]

Quote:

Originally Posted by memepool /img/forum/go_quote.gif These are direct drives though so I would proceed carefully as regards lubing. Did you get a manual? Have you tried contacting Denon as they are still selling pretty decent new direct drives and should be able to advise on lubricants as I doubt they've changed their motor design since the 80s.

Good Idea, I have a manual for the DP35F - there is no mention of a need for ort indeed how to lubricate - I will shoot Denon a line.

Quote:

I think you hit the nail on the head with acoustic feedback. Remember DDs are designed around the principle of high mass supports so really they need to be on a solid plinth or concrete floor. The cheaper ones with plastic composite plinths like you have even more so.

The 30L is much heavier than the 35F but the "rumble" is the same on both , if it were a bearing issue I would have expected the noise levels to be different but I am remembering my rega which was belt drive I guess DD dont have the same thing ?

Quote:

If you can't do this then layers of dense material like marble or granite (chopping boards) with foculpods in between will help. Also removing the lid whilst playing will help. If you absolutely need to site it on a table then a suspended subchassis design is much more suited.

Sadly yes a table is my only option at present. Say I sell both the Denons and have $200 (absolute final not a penny more) to spend could I get a half decent subchassis TT (used) with cart for that.

I have already sunk more into this than I really wanted to what with the phono stage, the NAD3020 cos they have decent phono stages, the step-up transformer cos I didnt notice the NAD was 240V (Doh !) , the Rotel RX303 (which had a terrible phono stage causing me to buy a separate phono stage), the Nikko NR700 (okay, I like Nikko amps and cant blame anyone for that) , the Sorbothane Balls, the replacement stylus, the sewing machine oil, the record cleaning kit, oh and $20 plus shipping for 130 LPs, including 50 Beethoven LPs, I also wish some LP sellers would be more accurate with their descriptions - VG++ my arse !

Oh, I am probably going to need a new cart to sell the DP30L - what could/should I get for $30 used off ebay ?.

The funny thing is that if I ignore all the spuriae the sound isnt bad at all

 

[Publius]

Turntable manufacturers use a weighted figure for rumble, IIRC. So -78db may wind up being higher unweighted.

What exactly does it sound like? Is it just a lot of noise at the deep bass regions (30hz and below)? Or is it at higher ranges than that? Are you using a sub?

FWIW, I have quite monstrous rumble from my MMF5+AT440ML when I look at a spectrum plot, but it doesn't effect music listening for the most part.

 

[hciman77]

Quote:

Originally Posted by Publius /img/forum/go_quote.gif Turntable manufacturers use a weighted figure for rumble, IIRC. So -78db may wind up being higher unweighted. What exactly does it sound like? Is it just a lot of noise at the deep bass regions (30hz and below)? Or is it at higher ranges than that? Are you using a sub? FWIW, I have quite monstrous rumble from my MMF5+AT440ML when I look at a spectrum plot, but it doesn't effect music listening for the most part.

Just out of interest what is the scale of the rumble you are getting ? - I had a Rega back in 1984, still have in storage, and that is a similar design (?) and that was always very noisy.

Off topic my local record store had a MMF2.1 and it seemed very noisy with a similar low end rrrrrrrrrrrrumble, mind they had it turned up to ear splitting volumes.

On the Denons It seems to be a constant low frequency rrrrrrrrrr sound but not a hhhhhhhhhum, a sort of rolling sound, definitely low end...Once the music starts getting loud it is masked but for classical music where there are lots of quiet passages it breaks through a lot.

I listen on headphones only (HD580) so there is no speaker related feedback. My feeling was that it was the motor vibrations bouncing back from the table and thence being picked up by the cart/arm.

Of course it may be that with headphones I can hear even -78db rumble which I would miss on speakers, dunno, my old Nikko amp barely hits -70db SNR yet this is never noticable on speakers with rock music, but it is hiss rather than low end noise

 

[JadeEast]

What happens if you listen to your TT with no power to
the deck & just spin it by hand. Just curious if you are possibly
hearing phono stage noise.

 

[hciman77]

Quote:

Originally Posted by JadeEast /img/forum/go_quote.gif What happens if you listen to your TT with no power to the deck & just spin it by hand. Just curious if you are possibly hearing phono stage noise.

Do you mean with the cartridge on the record ?, I will give it a try.

In any case the phono stage is definitely noisier than I had hoped, despite its supposed 85db SNR, with the amp on full the noise is quite audible both with and without the TT connected but not playing - with the phono stage disconnected the amp is silent at all volumes - however when I adjust the volume down to normal listening levels the phono stage noise doesnt seem to be audible, nevertheless I will experiment with that some more. Having said that I am also going to be experimenting with a couple of amps (NAD/Nikko) with built-in phono stages.