Sources of noise and how to deal with them....

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Wayner

Sources of noise and how to deal with them....
« on: 21 Jul 2010, 03:00 pm »
I thought this would be a good thread for everyone, including newbies. As we all know (or should), vinyl is a very mechanical medium. It uses mechanical waves on a disc, converting mechanical energy to electrical energy. The problem is, there usually are more things vibrating then just the stylus, but get captured by the pick-up coils anyway. The coils can't interpret the difference between music and something on the table vibrating, so it gets thrown in with the rest of the mix. Of course, this clouds and distracts from the original musical content, and in severe cases, destroys the re-creation all together. How do we stop the unwanted noise from entering the music stream?

For starters, I recently purchased an AR ES-1 tonearm. It was in wonderful condition, but had a few issues. One significant issue was the VTF dial on the counterweight. You, know the one. Almost every table has this dial. It's used as a reminder to indicate the current tracking weight. Well, mine was very loose. I originally packed some plasticlay in 3 spots to shut it up, while I was working on my TT project, but now I decided that the plasticlay had to go. The solution was some sewing thread. I wrapped some thread inside in the gap between the dial and the counterweight and tied a knot. I then continued to wrap more thread around the shaft in between the dial and counterweight. Then I tried to see if the dial tightened up. Oh, too much, so I backed some thread off and kept testing the dial until it was to a point where I could move it somewhat freely, but it would not rattle. I tied another couple of knots and cut off the excess. Mission accomplished.

This is just one of many noise makers found on TTs. I bet you guys have some of your own stories and hopefully some remedies to share.

Wayner

neobop

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Re: Sources of noise and how to deal with them....
« Reply #1 on: 22 Jul 2010, 01:15 pm »
Seems to me the potential for mechanical noise are almost limitless. All it takes really is for 1 loose bolt or screw somewhere to compromise performance. Things we normally take for granted like oil or grease in the main spindle bearing or motor lube every year or 2, can also turn into a problem. Physical isolation and acoustic feedback are also considerations.

The potential for electronic noise is also greater than high level sources because of the need for much higher gain. Any noise is amplified more, and the tiny phono voltages are more susceptible.

I was somewhat reluctant to reply with anecdotes, because they are so numerous (I used to set up TTs professionally), nothing really stands out as being a common problem, except oversight in general. You've just finished aligning your new cart, when the phone rings. After a lengthy conversation you forget to tighten down the cart mounting screws, and can't figure out why it doesn't sound so good. That sort of thing can happen, and does.

Now that I've scared off potential newbies, let me say that many problems are common sense things that are easy to figure out and rectify. Every once in a while check things like the arm mount being secure, arm movement unhampered, and those cart screws. Recently I bought an old Denon 1250 table with a Magnapan Unitrac arm. The nut holding the arm in place was loose and I didn't realize until the base moved slightly LOL.

If you check your spindle and motor oil every 3000 mi, and clean and dress your belt every once in a while between replacements, and generally take a hands on approach for any loose ends, you can have yrs of trouble free performance. BTW, to clean a rubber belt - use alcohol. After it's dry put some talc in the palm of your hand and pull the belt through - both sides. Then shake off the excess. Clean the pulley with a Q-tip and alcohol.
neo


BobM

Re: Sources of noise and how to deal with them....
« Reply #2 on: 22 Jul 2010, 01:24 pm »
Well, there's airborne noise, there's noise transmitted through the floor/stand, there's surface noice, there's other mechanically generated noise from the TT or arm itself, there's compressor noise (for those who have vacuum hold-down or a linear tracking arm), there's tube rush noise, there's ground loop and transformer hums, etc. Each one has it's own set of suggested solutions and each is very different from the other.

There's also musical companions who won't shut up noise, farts (with accompanying noise and smells), snoring noise (for those bored with the music), kids running around noise, spousal task-list reminder noise, telephone ringing and Blackberry e-mail arriving noise, humidifier/dehumidifier noise, dog barking and scratching and whining for food noise, inner ear ringing noise (I sympathize with anyone who suffers from this one because the solution doesn't exist), and those voices in the back of my head noise telling me that something isn't quite right and I need to tweak the system to correct it.

All of these just suck the enjoyment out of our hobby. Or is it all of these keep us coming back to our hobby to get away from it all for a while and add to those moments when we just sit back, relax and enjoy it all the more?



bside123

Re: Sources of noise and how to deal with them....
« Reply #3 on: 22 Jul 2010, 02:18 pm »
Here's a simple one and relatively effective for possibly 2 kinds of noise: Remove the hinges from the dustcover and the table. When playing a record, use the TT with the dustcover completely off. When finished replace the dustcover. 1) No hinges - no potential rattles... less screws, hardware, etc. 2) No dustcover - less vibrational resonance (feedback) in contact with the deck. Cleaner highs, greater resolution in the bass, more detail in the mids.

Ericus Rex

Re: Sources of noise and how to deal with them....
« Reply #4 on: 22 Jul 2010, 02:56 pm »
After it's dry put some talc in the palm of your hand and pull the belt through - both sides.

What does the talc do?

WGH

Re: Sources of noise and how to deal with them....
« Reply #5 on: 22 Jul 2010, 03:26 pm »
Some turntables have an internal transformer, moving it to an outboard power supply can eliminate another potential source of hum and vibration. The Harman Kardon tables benefit greatly from this mod, the result is increased clarity and focus.

Wayne

rcag_ils

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Re: Sources of noise and how to deal with them....
« Reply #6 on: 22 Jul 2010, 04:27 pm »
And there's something called inherent motor noise, certain type of turntable design have the platter sitting directly on top of the rotor, making the platter part of the rotor. Since there's no such thing as noiseless motor, ALL mechanical devices make noise, even the air around the motor being moved while the motor's turning makes noise. When the motor's energized, the magnetic field makes noise right below the platter in such design. The only way to get rid of such noise is replacing the turntable as a whole.

TheChairGuy

Re: Sources of noise and how to deal with them....
« Reply #7 on: 22 Jul 2010, 05:25 pm »
Great topic!

As a primarily mechanical device...there are lots of places where 'noise' can enter.  The neat thing is that even mere mortal, non-technical types can dial out various sources of noise with time and attention. 

While digital is a set-up and forget medium - there's little most of us mere mortals can do about noise or other issues - we can and do with turntables.  A turntable is a tweekist heaven and nightmare all in one!

Feedback is the biggie I find.  The more you can do to isolate our table from airborne sounds reverting back to the table...the better your analog front end will sound.

There's a large list of other sources of noise that I want to expand upon later when I have more time to write.

Great topic and help on something we all experience in this oft-frustrating hobby of ours.

John

Wayner

Re: Sources of noise and how to deal with them....
« Reply #8 on: 22 Jul 2010, 07:17 pm »
I found another source on my new TT project I call ARCom. It made a rattle when I would tap the plinth and after some investigating, it was the outer platter, rattling against the inner platter. With 3 very small beads of plasticlay at 120 degrees on the mating surface, I was able to knock that completely down.

Wayner

neobop

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Re: Sources of noise and how to deal with them....
« Reply #9 on: 22 Jul 2010, 07:49 pm »
What does the talc do?

The talc conditions the surface of the rubber after cleaning. Not sure exactly how, but it seems to work. Ever leave a rubber band laying around then try using it months later? Ouch!! Well, talc is to rubber like lotion is to skin.
neo

drphoto

Re: Sources of noise and how to deal with them....
« Reply #10 on: 22 Jul 2010, 08:12 pm »
Cool discussion.

For the most part, I'm really happy w/ the iso I've gotten from the Mapleshade stuff.

However, this post did make consider whether I should have tried keeping the 'lil SS phono pre I'd bought (and sold) and putting the TT in another room and running super long IC's to the line pre. (bypassing the bulit in phono section....I'm must supposing you can't send those low level signals very far......but I'm obviously no expert)

And if so, where would one find such long IC's? Custom made or DIY I'd guess.

Anyone gone this route? That maybe the only way to totally knock down the vib problem, but at what cost? (Sonically, not monitarily) If you boost the signal to line level near the deck, can you then run 10-12 meters worth of cable to the pre?

BTW: I'm seriously loving the vinyl return. Big time fun. I seem to find about 3 out 4 of the used records I've bought sound great. That's not a bad batting average.

Thanks for your consideration of this issue.

j

Wayner

Re: Sources of noise and how to deal with them....
« Reply #11 on: 22 Jul 2010, 09:00 pm »
The talc conditions the surface of the rubber after cleaning. Not sure exactly how, but it seems to work. Ever leave a rubber band laying around then try using it months later? Ouch!! Well, talc is to rubber like lotion is to skin.
neo

neo,

AR always recommended talc on the belts to actually promote slippage, which in turn, helped their underpowered motor to spin up and eventually drive the platter. I think it also helps the life of the belt as you have said. I think even VPI recommends this for their round belts, at least I thought I read this some where.

Cool discussion.

For the most part, I'm really happy w/ the iso I've gotten from the Mapleshade stuff.

However, this post did make consider whether I should have tried keeping the 'lil SS phono pre I'd bought (and sold) and putting the TT in another room and running super long IC's to the line pre. (bypassing the bulit in phono section....I'm must supposing you can't send those low level signals very far......but I'm obviously no expert)

And if so, where would one find such long IC's? Custom made or DIY I'd guess.

Anyone gone this route? That maybe the only way to totally knock down the vib problem, but at what cost? (Sonically, not monitarily) If you boost the signal to line level near the deck, can you then run 10-12 meters worth of cable to the pre?

BTW: I'm seriously loving the vinyl return. Big time fun. I seem to find about 3 out 4 of the used records I've bought sound great. That's not a bad batting average.

Thanks for your consideration of this issue.

j

drphoto,

Longer leads can be had, by companies like www.bluejeanscable.com, but remember, as cables get longer, especially with MC cartridges, you will have high capacitance and resistance will become a factor. High capacitance will start to affect high frequency response of your music (acting like a cross-over network) and the high resistance from the long length may affect small voltages like .3mv stuff.

It's just generally not a good idea. Try to keep them 1 meter long if possible, 2 if you really need it. The bluejeans cable is about 12pf per foot, very low, but other brands may be that per inch.

Wayner

drphoto

Re: Sources of noise and how to deal with them....
« Reply #12 on: 23 Jul 2010, 12:48 am »
Wayne, what I was suggesting, was to use a stand alone phono pre that would be near the deck to boost the low level signal up to live level and then go through the long leads to the line pre.

neobop

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Re: Sources of noise and how to deal with them....
« Reply #13 on: 23 Jul 2010, 10:28 am »
Wayne, what I was suggesting, was to use a stand alone phono pre that would be near the deck to boost the low level signal up to live level and then go through the long leads to the line pre.

Hi Dr,
Yes, you can do that AFTER the phono stage, but I think you'll find that it's a pain to have to go to the next room to turn over the record.

Abandon the idea of a wall shelf ?? Installing one does require a bit of work, but it's much more effective than anything else (in room). Of course you have to be able to locate it in an appropriate place.
neo


95Dyna

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Re: Sources of noise and how to deal with them....
« Reply #14 on: 23 Jul 2010, 03:46 pm »
neo,

AR always recommended talc on the belts to actually promote slippage, which in turn, helped their underpowered motor to spin up and eventually drive the platter. I think it also helps the life of the belt as you have said. I think even VPI recommends this for their round belts, at least I thought I read this some where.


Hi Wayne,

Great topic and of universal appeal.  You are right about VPI recommending the talc on their round belts.  I just installed my new VPI Classic and ran accross it in the manual.  BTW, if you are buying a new table and want to greatly minimize and/or eliminate many of these noise problems the VPI Classic is worthy of your consideration.  For starters it is its own isolation device.  Harry Weisfeld tested it sitting on a garden variety 2" butcher block shelf sitting next to a speaker with 2-15" woofers and could detect no measurable resonance.

Bill

drphoto

Re: Sources of noise and how to deal with them....
« Reply #15 on: 23 Jul 2010, 04:23 pm »
Haven't given up on trying a wall mount. I was just thinking out loud here.

Wayner

Re: Sources of noise and how to deal with them....
« Reply #16 on: 23 Jul 2010, 05:00 pm »
Wayne, what I was suggesting, was to use a stand alone phono pre that would be near the deck to boost the low level signal up to live level and then go through the long leads to the line pre.

Drphoto, I have to tell you that even doing it this way may cause problems, even tho you are now at line level voltages (1-2 volts), if you have long interconnects with high capacitance, you will alter the sound even out of your preamp. I think most will agree that the golden rule is short as possible leads all around.

This brings up another good point. Power amplifiers and preamplifiers all have transformers in them (toroidal or core and coil) and these generate large magnetic fields. Lesser shielded cartridges can take advantage of some distance from amplifier just to get away from it's magnetic field. Now you might need a 1.5mm interconnect, and it's a good trade-off to better isolate the TT from the transformers.

Again, life teaches us that there is no pure answer, but a series of best option compromises, favoring that remedy that causes the least harm.

Wayner

drphoto

Re: Sources of noise and how to deal with them....
« Reply #17 on: 26 Jul 2010, 04:03 pm »
I'm still getting noise from my phono pre. I just ordered 3 more pairs of tubes to try to find a really quiet set. When I first got the Tung-Sol, I thought the problem was solved as it was so much better than what I had. But more careful listening, especially at higher gains slows it's still there. The low rumbly stuff is much more of an issue than hiss.

I might have to revert to the stand alone phono pre option again, if this doesn't work.

Just something for others to look into, if you have mysterious noise.

I also remove the dust cover while playing a disk. Rega says leave it on, but it acts like a big resonance chamber.

TheChairGuy

Re: Sources of noise and how to deal with them....
« Reply #18 on: 26 Jul 2010, 04:14 pm »
I also remove the dust cover while playing a disk. Rega says leave it on, but it acts like a big resonance chamber.

Totally - remove it entirely.  I do with all of my decks....it's a cinch to re-insert back into hinges after playing a while even on decks with them (most Japanese decks had them neatly integrated and standard)

In my experiments of the past...I found fluid damping very helpful to tame a certain type of low frequency noise (perhaps that's rumble?) from nearly every cartridge. It helps warp tracking...tho warp issues can be ameliorated with the use of outer ring clamps nowadays.

A thick maple block with brass feet pointed straight down into it from the table seems to erase a layer of grundge with all tables tried for a cleaner presentation.  I suspect that absorbed energies...which translates to a certain type of noise we experience with vinyl.

Ditto for the wonders of plast-i-clay.  If your deck is hollow inside...it's begging for a clay treatment.  You will be glad you did, afterwards...as was explained recently to me, it's shifting the higher frequency sounds inherent in your deck to lower frequencies not altogether eliminating it (cause you cannot, unless its converted into something else like heat or light), but it helps a ton in removing a type of 'noise' that you wouldn't know otherwise existed lurking in your deck.

John