Tonearm Damping?

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dlaloum

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Tonearm Damping?
« on: 8 Oct 2011, 06:40 am »
Hi,

I've noted that you suggest (and a number of people use) the HAL-O-Jr's for use with tonearms...

How should these be used?
How does one find the best spot to place them?
what frequencies do they damp?

thanks

David

Herbie

Re: Tonearm Damping?
« Reply #1 on: 8 Oct 2011, 02:35 pm »
Hi, David. HAL-O JR (or Mini Jr. for narrower tonearms) is simply placed on the tonearm, either laterally or by sliding the damper from the headshell end along the length of the tonearm into position.

About 1/3 of the tonearm length down from the headshell is the default position. This usually provides satisfactory results. Ideal positioning, however, can only be determined by experimentation and audition. Sometimes they'll do best closer to the headshell, sometimes close to the pivot. (With each change of position, the counterweight should be adjusted to compensate.) One JR is usually sufficient, though a pair sometimes works even a little better (one near the pivot and one near the headshell).

HAL-O JR damps virtually any vibrational frequency that is present on the tonearm. 50Hz-60Hz frequencies from motor hum are common and these vibrations are usually tamed very well (though this hum might still penetrate the platter). Tonearm tube resonances are usually reduced below any audible level. Higher frequency micro-vibrations that cause glare and other problems are also tamed.

Steve
Herbie's Audio Lab

jostber

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Re: Tonearm Damping?
« Reply #2 on: 14 Dec 2011, 03:36 pm »
Do you have a recommendation for damping of a universal Technics tonearm for the SL-1200 MKII?


Herbie

Re: Tonearm Damping?
« Reply #3 on: 14 Dec 2011, 05:56 pm »
For the SL-1200 MkII tonearm, titanium HAL-O JR.

HAL-O JR

Steve
Herbie's Audio Lab

jimdgoulding

Re: Tonearm Damping?
« Reply #4 on: 14 Dec 2011, 06:02 pm »
Those are good questions.  If you can figure it out, I believe a person can use simple modeling clay tho perhaps not to the same effect of Herbie's.

Herbie

Re: Tonearm Damping?
« Reply #5 on: 14 Dec 2011, 06:29 pm »
Modeling clay is not a good damping material. Rope caulk (available at hardware stores) however, is very good. You can knead it, shape it, press it into place similarly to modeling clay.

Steve
Herbie's Audio Lab

SET Man

Re: Tonearm Damping?
« Reply #6 on: 19 Mar 2012, 11:18 pm »
Hey!

   Wouldn't  the result of using the damper on tonearm also have to do with increasing the total mass of the tonearm and changing the overall tonearm/cart resonance? 

Take care,
Buddy  :thumb:

dlaloum

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Re: Tonearm Damping?
« Reply #7 on: 18 Oct 2013, 08:21 am »
Hi Steve/Herbie,

I left this subject alone for a while, but recently saw a Denon 307 tonearm for sale, and read the brochure for it (on VE) ....

In the brochure it shows a resonance frequency response for a "conventional" arm - with a clear resonance at around 250Hz. (the Denon arm of course has a vibration damping mechanism that eliminates this)

Looking at many Frequency response plots i have made of various cartridges over the last 3 years, it is clear that my JVC S-Arm has a 250Hz resonance ....

So I revisiting this topic with something a little more specific - have you measured the impact of any of your damping solutions when looking at frequency specific issues?

Have you measured the impact of the Hal-O Jr in frequency terms.... is there such a thing as a measured specification chart of damping (in db?) vs Frequency?

I have before me a menu of potential damping methods:
- Heat shrink or tape the arm
- Cotton fill arm tube
- foam ear plugs in arm tube
- Hal-O Jr
- Dots on the arm (at nodal points? presumably nodal points would vary by frequency?)

Unfortunately, nowhere have I seen actual measurements of damping effect for differing methods so I could focus in on the one (or more) most likely to resolve my issue....

thanks & bye for now

David

bardamu

Re: Tonearm Damping?
« Reply #8 on: 18 Oct 2013, 10:25 am »
Hello,
Decades ago i did built my own fishing rods and i remember making ''coils'' from the same material and technigue as used to mount the rod guides would make the rod stiffer. It is a simple technique. Sure something can be found on the internet how to do it. Can use a fabric that has some '' dampening '' character
Sincere greetings, Edward

dlaloum

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Re: Tonearm Damping?
« Reply #9 on: 18 Oct 2013, 10:44 am »
Hi Edward,

yes there are also suggestions using various types of tape (duct, electrical, teflon....) wrapped around the arm - I am sure that would have an influence... the question is what influence?

My nerdy side is unwilling to go ahead with a mod without knowing its outcome .... unless I am doing it for the purpose of measuring the various mods.... a different exercise!

bye for now

David

bardamu

Re: Tonearm Damping?
« Reply #10 on: 18 Oct 2013, 10:57 am »
Hello David,
But the technique used for the fishing rods will gave a good '' connection '' between the wire and the rod so its effect will be bigger. Using the right tecnique it also can be removed easily. With the fishing rods it would be varnished afterwards. Edward

Herbie

Re: Tonearm Damping?
« Reply #11 on: 18 Oct 2013, 02:19 pm »
Hi, David. HAL-O JR and other Herbie's Audio Lab damping products are not frequency-specific. They diminish the whole spectrum of frequency vibrations. Specific frequency/dB ratios will vary somewhat from one vibrational environment to another and among different tonearms. You'll get varying degrees of diminished vibration, not so much a "shifting" of resonance frequency or linearity, resulting in a more faithful musical rendering. Typically, the greater a specific frequency's amplitude, the more it will be diminished.

HAL-O JR will reduce a tonearm's resonance frequency substantially, as well as the full gamut of micro-vibrations affecting the tonearm. A tonearm, like all solid materials in an audio system, does not vibrate only at a specific, dominant resonance frequency, but also suffers micro-vibrations throughout the audible spectrum and well beyond. Oftentimes, it's micro-vibrations of much higher frequency and much lower amplitude that cause some of the glare and grunge, and other anomalies, in music. For essential micro-vibration control, you need to address vibration with a whole-spectrum approach.

Among the materials mentioned in your post, each of the ideas is viable (cotton has perhaps the least potential, though). Plumber's Teflon tape, the kind you wrap around pipe threads, can be very effective at tonearm damping, wrapped several layers thick at a specific location or locations on the tonearm, or around its length. Experimentation/audition is about the only way to determine the most appropriate approach for a given application. What's appropriate for one tonearm/system will not necessarily apply to the next. Trying to pre-predict or pre-engineer a solution can be futile compared to actual trial-and-error auditioning by ear.

Acute micro-vibrations that cause loss of ambient vitality and "live" accuracy are often of such low amplitude that they are imbedded within the noise floor of electronic measuring equipment, so charting them can be illusive, measuring them impossible. Reduction or elimination of these vibrations is readily audible, however, to the discerning listener.

Best regards,

Steve Herbelin
Herbie's Audio Lab

WireNut

Re: Tonearm Damping?
« Reply #12 on: 18 Oct 2013, 04:45 pm »
I've seen rubber washers spaced along the length of the arm. Seems like an easy and inexpensive tweak to try. Shrink wrap seems like it would work also but the thought of heating it up on the arm with those skinny wires inside keeps me from trying it.

 

BrentG

Re: Tonearm Damping?
« Reply #13 on: 19 Oct 2013, 04:31 pm »
I'm interested in trying the HAL-O JR. to dampen tonearm resonance.

I'd prefer to go with titanium rather than PTFE to minimize the additional mass on the tonearm. However, the HAL-O JR. will have to be installed laterally (my tonearm does not have a removable headshell).

Is it possible to slip the titanium version laterally onto a tonearm (perhaps by first removing the damping pads from the ring - and then, of course, reinstalling the damping pads on the ring after the ring is around the tonearm)?

Thanks,
-Brent

Herbie

Re: Tonearm Damping?
« Reply #14 on: 19 Oct 2013, 08:49 pm »
Yes Brent, that's possible. You can also bend the titanium C-ring a little with needlenose pliers to accommodate placement and then bend it back once it's in place.

Steve Herbelin
Herbie's Audio Lab

BrentG

Re: Tonearm Damping?
« Reply #15 on: 22 Oct 2013, 03:44 pm »
Yes Brent, that's possible. You can also bend the titanium C-ring a little with needlenose pliers to accommodate placement and then bend it back once it's in place.

Steve Herbelin
Herbie's Audio Lab

Thanks, Steve.
My order is in.
-Brent