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  #51  
Old 03-05-2005, 05:14 AM
djnick01 djnick01 is offline
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Darryl

[quote]Originally posted by darrylfunk

acrylic platter = i think i'm the only person to do this.

some of the decoupled heavy weight sound more pleasant but lose detail and speed so its horses for courses.


Could you please tell me more about the acrylic platter? Link maybe?

Also, when you say "decoupled" re; the heavyweight what do you mean?

I have Regas in unmodified condition on my decks and have been saving up a bit to complete the mods. The Incognio rewire kit is
probably first on my list. The counterweight thing has been bugging me a bit. I have even considered just going with a stock Rega RB300
steel counterweight, as its cheap and looks to do pretty much whats
required. Also a bit cheaper. Though thats not really the point with all this

Cheers, Nick
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  #52  
Old 03-05-2005, 10:08 PM
shuglu shuglu is offline
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Hi darrylfunk

The lower centre of gravity offered by both the techno weight and the heavyweight are the same principle, but the heavyweight benefits from fitting closer to the pivot point due to it's mass.

Check the two links below for reviews on both the arm and counterweight. The floating bearing design is a contentious issue within the audiophile market and a good case exists both for and against it, although I must say that I have not yet experienced any negative results.

http://www.6moons.com/audioreviews/o.../silver_2.html

http://www.positive-feedback.com/Iss...eavyweight.htm

Could you explain the benefits of the acrylic platter you mentioned.

S
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  #53  
Old 03-06-2005, 03:32 PM
darrylfunk darrylfunk is offline
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which

which heavyweight counterweight are you talking about.
the expessimo or kerry design one or is it the "Heavy weight" none of these are like either the michell or origin live counterweights.
IME the michell is the best i have tried out of all of them.
i use an acrylic sub platter to better damp the metal platter and reduce the stylus needletalk by improved impedance matching.
acrylic is non crytaline like vinyl too so energy has less physical boundaries to move through.
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  #54  
Old 03-06-2005, 03:53 PM
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dancindave dancindave is offline
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Still curious about the acrylic. Do you replace the entire Technics metal platter with acrylic?
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  #55  
Old 03-09-2005, 05:44 AM
darrylfunk darrylfunk is offline
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hi dancin and shuglu

i use a 4mm acrylic disc with a label sized dished centre and
basically bond it to the metal platter.
it does a few things firstly adds a little mass that helps damp the platter and smooths rotation a touch.
then the thin felt mat rests on top then the record.
the acrylic is closer in material terms to a vinyl record and this means that the mechanical impedance is closer to ideal this means low level signals are tracked better and the difference in quiet to loud signals is improved. better more reduced surface noise and more stable stereo is another effect of this mod.
lots of high end turntables use acrylic in there platters.
michells , origin live , roksan , vpi , sota , townshend , pink triangle , loth - x , scheu , transrotor , pro-ject , reson and many others.
the best emt turntables used a light plastic type material for similar reasons.
not everyone agrees with this usuage some people perceive a softening of sound but i have found that the attack,decay,release and sustain of notes and beats are more accurate and more faithful to the original recording.
by the way first impressions of my new audio technica carts is superb.
will post again soon.
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  #56  
Old 03-09-2005, 01:10 PM
grizz grizz is offline
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Re: hi dancin and shuglu

Quote:
Originally posted by darrylfunk

by the way first impressions of my new audio technica carts is superb.
will post again soon.


yes, please...
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  #57  
Old 03-09-2005, 02:27 PM
shuglu shuglu is offline
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I am intrigued by your reply as it is the obvious step nobody has taken.

Do you or can you produce the acrylic mod to order and what method of bonding have you used. Does acrylic come in differing grades and does this contribute to it's performance.

Have you had the chance at a/b testing against a standard platter, and if so, how much of an impression does the mod have on the first time listener. Is it drastic or subtle.

Just a short last question:

In your experience, what does the 'burning in' of audio cables offer to the DJ. In specific, tone arm cables. Just interested in your opinion.

S

Last edited by shuglu : 03-09-2005 at 02:31 PM.
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  #58  
Old 03-10-2005, 03:11 PM
kingk kingk is offline
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Re: hi dancin and shuglu

Quote:
Originally posted by darrylfunk

then the thin felt mat rests on top then the record.
the acrylic is closer in material terms to a vinyl record and this means that the mechanical impedance is closer to ideal

Hi Darrylfunk.

Do you still benefit from impedance matching if the felt mat isolates the record from the acrylic platter ? Do you have a link with some theory on this matter ?
Do you think it's a good idea to isolate the Origin Live armboard from the TT base ? I have found a picture of the Gyrodeck armboard isolation. The same thing can easily be done with the OL armboard.



By putting an acrylic + rubber ring under the OL armboard the height can be adjusted at the same time (I know you are not a fan of VTA adjustment, and you are probably right).
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  #59  
Old 03-10-2005, 03:28 PM
darrylfunk darrylfunk is offline
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well here we go

my explanation is as follows....
i think tonearms should be rigidly mounted due to the fact
they are measuring the groove. any give means losses.
the turntable itself should be able to resist vibration.
secondly.
of course a felt mat reduces the impedance match but its still of a magnitude better to be on due to its self damping properties.felt is rigid at high frequencies and decouples at low frequencies.
i will post some links up for you including one were you can get acrylic platter tops at the weekend.
cheers guys.
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  #60  
Old 03-10-2005, 03:45 PM
kingk kingk is offline
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Thanks. Looking forward to the links and pictures.
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  #61  
Old 05-17-2005, 06:30 AM
shuglu shuglu is offline
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Isonoe appoint first US agents

Having posted the pictures of my modified SL1200 a few weeks back, I received a couple of PMs asking if the Isonoe Feet could be purchased in the US, rather than have to import a set from the UK.

Although the link isn't yet on the www.isonoe.com site, Kevin at KAB: http://www.kabusa.com/frameset.htm?/isonoe.htm now has them in stock. Alternatively, the www.choosefte.com organisation are selling them to the installation market as well.

Hope this info is helpful.
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  #62  
Old 05-17-2005, 11:37 PM
JOEY MADONIA JOEY MADONIA is offline
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Thumbs up

You should check out the isolators called, the ELIMINATOR.
Made in the U.S.A. (www.custommade.cc)
You don't have to give up the original adjustable foot that comes with the your turntable. And, it is adaptable to just about all makes of turntables.

LOL
Joey
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  #63  
Old 05-18-2005, 04:22 PM
thermionic thermionic is offline
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See attachment
Attached Images
File Type: jpg technics-foot2.jpg (35.1 KB, 440 views)

Last edited by thermionic : 05-18-2005 at 04:35 PM.
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  #64  
Old 05-18-2005, 04:24 PM
thermionic thermionic is offline
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Excuse the lengthy post, but we need to clear up some issues relating to the standard plastic Technics feet:

If plastic is such a good compound for the suppression of resonance, why do the world's finest tone-arm manufacturer (SME) use magnesium alloy?

Have you ever seen a bass-bin made from plastic?

As Darryl asserted earlier in the thread - in order to prevent the transmission of vibration, an ideal material should have the highest ratio of stiffness to mass (i.e. the highest stiffness for the least weight) – magnesium alloy has one of the highest ratios out of any available compound, and is favoured by tone-arm manufacturers for this reason (can anyone think of a more critical application for a material that keeps resonance at bay than a tone-arm?).

I have attached a picture in the above post showing exactly what's inside a standard SL foot...(Hi-tech huh?)

The standard foot is absolutely useless – once loaded, the spring compresses (try pushing your TT downwards to see how much movement there is), thus offering zero compliance – vibration is free to travel straight through the foot into the deck (with a decent gauge of compressed steel spring to ensure plenty of energy is transmitted), without any suspension / compliance to damp it whatsoever.

If the standard plastic SL feet were any use at all, no firm would have to bother making anti-vibration accessories…

There are numerous links on the Internet explaining why materials such as plastic should not be used in anti-vibration products, try this one for starters: http://www.fabreeka.com/tech/practic...iderations.pdf (It is not from an audio company, but the principles are the same)

Taken from link:
Quote:
For an isolator to provide vibration isolation, it must be able to deflect. REMEMBER: NO PROTECTION WITHOUT DEFLECTION. In general, the more the mount deflects, the more vibration isolation that will be provided. However, if the support structure below the mount or the equipment support below the mount is too soft, the structure will take some of the deflection which is intended for the mount. This reduces the effectiveness of the mount, and may also result in fatigue problems in the structure

Please note that I'm not trying to start an argument here, merely endeavouring to minimise the propagation of misinformation.

Peace,
Justin
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  #65  
Old 05-19-2005, 01:22 PM
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daveg daveg is offline
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Stiffness

In respect to tonearms, stiffness is good thing but the natural resonance of various materials and how they interact with each is going to be a issue also.

I take it we are still on turntables used in high SPL enviroments?

Justin, Please now cut up the rest of the deck including tone arm as Technics might have got it wrong?

There is lots of rubber in there also

I'm sure the isonoe is OK though and a improvement. Are those the industrial mounts mentioned in RS cat. mentioned?
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  #66  
Old 05-19-2005, 04:01 PM
thermionic thermionic is offline
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Re: Stiffness

Quote:
Originally posted by daveg
In respect to tonearms, stiffness is good thing but the natural resonance of various materials and how they interact with each is going to be a issue also.

I take it we are still on turntables used in high SPL enviroments?

Justin, Please now cut up the rest of the deck including tone arm as Technics might have got it wrong?

There is lots of rubber in there also

I'm sure the isonoe is OK though and a improvement. Are those the industrial mounts mentioned in RS cat. mentioned?

With regards to the "natural resonant frequency" issue - the criteria are the same, be it a tone-arm, or support. You don't want your arm to "ring", nor the supports... (The standard Technics arm is magnesium alloy btw)

Rubber (Sorbothane is obviously better) makes a great compound for preventing the transmission of energy, but for it to work at maximum efficiency, it needs to be supported by a material that is extremely rigid and preferably light (check the equation in the link from last post). In order to concentrate on the compliant damper part, which is where the decoupling will come from, you have to make sure the supporting strut is highly rigid, or compromise efficiency of the damper. You also need to ensure that the strut supporting the compliant part has as high-a-resonant-frequency as possible, so as to minimise transmission to the damper in the first place.

A tone-arm "supports" the cartridge, therefore it needs to be made from a material that is exceedingly rigid, dense and light at the same time. The criteria for choosing any kind of "support" (that is required to be inert acoustically) are the same as choosing a tone-arm material - you want the densest, most rigid material available, but it needs to be light for energy transfer reasons (to save me getting RSI, read Darryl's earlier post).

"Oak cone" feet have many advocates for monitor-support duties (including Pink Floyd's "Astoria" studio - one of the most hi-tech studios in the world) for similar reasons - oak is rigid, yet light.

There is no middle-ground here - you want a soft, compliant material for the damping, and something stiff but light to support the damper.

I suggest you take a blade to the Technics foot for yourself. As previously stated, once the foot is loaded, the spring becomes extremely hard due to compression, and is therefore unable to do its job, and instead of acting like a compliant suspension (its intended purpose), it becomes a direct pathway for vibration to travel.

I am an outspoken admirer of Technics' design - the only fault I can see with the SL is that it's built to a price, and I guess the market is considered too small for the development of a "high end" model.

Not sure if I posted this link before, but check it out to see earlier Technics models, before mass-production was a concern: http://de.geocities.com/bc1a69/technics_eng.html

Taken from link:
Quote:

National/Technics is one of the pioneers in developing Direct-Drive turntables. This was the brand name under which the big japanese company Matsushita became a big player in the audio business back in the 60s. 1969 Technics introduced the first direct-drive deck, the Technics SP-10. Successfull as it was Technics developed a number of decks in the 70s that are considered among the best Direct-Drives ever built. In common sense the sonics of the quarz-controlled models of the second half of the 70s are better than their ancestors. Besides the famous SP-Series which were all offered without a plinth there was also the SL-series with some of them offered without a tonearm which will make for quite a good deck even today.


That would be my sentiment exactly.

One comment I will make is that I find it surprising to see so many discussions relating to electronics, yet if vibration disturbs the pickups, the performance of the electronics will be irrelevant, even if you have the finest mixer and amps in the world.

Cheers,
Justin

btw, I would never recommend industrial supports because they will be optimised for a much heavier load - if the pressure from the TT is say, 4KG, you want the damper to be in its most efficient region at that load - industrial supports that can handle 100KG will never be optimally effective at 4KG.
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  #67  
Old 05-19-2005, 05:26 PM
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Turntable Mods

A tone-arm "supports" the cartridge, therefore it needs to be made from a material that is exceedingly rigid, dense and light at the same time. The criteria for choosing any kind of "support" (that is required to be inert acoustically) are the same as choosing a tone-arm material - you want the densest, most rigid material available, but it needs to be light for energy transfer reasons (to save me getting RSI, read Darryl's earlier post).

The above comments and other always point towards somewhat questionable mods which junk parts of exsisting designs and replace them with parts from alloy and perspex. These mods always seem to geared towards making a stiff structure.

My point is which I try to make frequently is that a Techinics arm is Headshell/rubber ring joint, alloy arm ,cast alloy bearing section, rubber rear stub section, alloy sleave, rubber ring and counterweight.

Check the rubber and number of parts. My opinion is that the arm was designed that way to reject vibration.
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  #68  
Old 05-19-2005, 05:38 PM
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Industrial Mounts

The RS mounts I was thinking of do go to low mass items. There was also the type of mounts for avionics electronics which I seem to remember seeing but these are miltary spec cost no object items. These used springs and a damping material to stop things going wild.

The Technics is semi-pro by original design, but wow! What other modern semi-pro item is anywhere near the quality?
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  #69  
Old 05-19-2005, 05:45 PM
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Vibration

We talk about vibration disturbing pickups!

I found a good copy of Shures audio test record, with a Stanton 680 it makes your teeth itch! I see why Stanton never did a test record!

As this is a DJ forum, perhaps it should be noted that our DJ carts suck in a major way.

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  #70  
Old 05-19-2005, 06:10 PM
thermionic thermionic is offline
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Quote:
My point is which I try to make frequently is that a Techinics arm is Headshell/rubber ring joint, alloy arm ,cast alloy bearing section, rubber rear stub section, alloy sleave, rubber ring and counterweight.

Check the rubber and number of parts. My opinion is that the arm was designed that way to reject vibration

That is an identical concept to the way the Isonoe feet are designed, and corresponds exactly with the theory in the last post I made - i.e. A stiff but light structure, coupled to a soft compliant damping component (It even includes the ball-bearing concept).

From a technical perspective, I fail to see where we're in disagreement Dave?

Fact: The Technics is built to a price, and fitting cnc-machined feet, or a "boutique" arm to it would jack the price right up (have you never heard of people fitting more powerful engines, or better brakes to a car? A touring car is far quicker than its road-going sibling, yet retains the basic monocoque - is it "questionable" to tune a car for a race? Would they be better off with a standard one from the high-st? Why should a TT be any different?).

Fact: Numerous clubs have solved feedback issues by retrofitting Isonoe feet.

Fact: Numerous hi-fi users have reported significant improvements in clarity when fitting Isonoe feet (particularly in the HF region where groove information is tiny, and highly susceptible to disturbance from vibration - check the link earlier in thread).

Fact: Numerous users (including Plastic People and Shorty / Stereo) have reported improvements by fitting Origin arms.

Fact: You may not like Origin arms, and are entitled to your opinion.

Please don't dismiss something as "questionable" unless you have a technical theory to back it up.

Peace,
Justin
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  #71  
Old 05-19-2005, 06:14 PM
thermionic thermionic is offline
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Quote:
The Technics is semi-pro by original design, but wow! What other modern semi-pro item is anywhere near the quality?

I couldn't agree more - it's a true classic, designed in the '70s before accountants took over.

Few products in the modern marketplace have as much integrity as an SL, and I believe the stock TT is under-rated for its performance, given the price-point.

J
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  #72  
Old 05-20-2005, 07:36 AM
darrylfunk darrylfunk is offline
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hear hear

just to second justin's comments.
regards.
darryl butcher.

p.s. the original technics arm is not as bad as some people say.
to prove my point , put a denon dl 103 moving coil on the standard deck and arm combo. it sounds fantastic.
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