Lewm, As you know, Henry, a shelf will be put into oscillation, by energy put into it. I know no such thing. And your common flaw of argument is precisely these types statement of false 'universal facts' without the provision of any scientific evidence. What I do know from a study of acoustics.....is that for any given material (and dependent on its thickness)......the majority of air-borne sound waves will be reflected or pass directly through. Certain frequencies (depending on the material in question) will be absorbed as heat....and/or transmitted in all directions within that material until they are all absorbed as heat. But I repeat....the majority of air-borne sound waves will be reflected or pass through the majority of materials. Every material (including liquids and gases) has a resonant frequency....and these can easily be measured via accelerometers and other more complex devices. The excitations of these resonant frequencies (and their harmonics) can be measured and heard (if within the audible sound spectrum). You have provided no scientific proof that the resonant frequency of my particular shelf (or anyone else's) has been excited by the air-borne sound pressure produced by the speakers? Of far more telling damnation IMO.....is the fact that you still....repeatedly and consistently.....refuse to address the effects of these 'resonant frequencies' on:- 1. The Platter 2. The Spindle 3. The Motor 4. The Pulley/s 5. The Belt 6. The Tonearm 7. The Headshell 8. The Cartridge 9. The Cartridge Screws 10. The Cantilever 11. The Stylus 12. The Record You hyperventilate over a 'resonating plinth' or shelf....which presumably you believe will 'transmit' its obscenities into any or all of the above mentioned turntable parts and thus contaminate the reproduction chain......yet you appear to have no concerns for the 'resonating vibrations' transmitted directly into all these above mentioned parts? Doesn't this in any way appear comedic to you? Or is it just me? |
Dear Raul, The most frequent quote about Spinoza is: 'Omnis determinatio est negatio'. In this 'spirit' Popper arques : 'we should not defend our theories but try to refute them.' Henry is negating the existance of 'some phenomena' which are postulated by Lew. Considering the fact that our forum is about the knowledge how our gear
works I would think that Henry's contribution is very important. This means that your 'scientific inclination' is very questionable. As I mentioned before your,uh, ' phylosphical statements' are also very questionable.This is an indication of your lack of 'phylosophical' education.
Regards, |
Halcro,
*Many scientists believed the Higgs particle exists, before there was evidence to support that.*
**True......but there were observable phenomena which could only be explained by the existence of 'something'?
This lead to a 'thesis' to explain this phenomena and then a search or test to prove the 'thesis'.
Most of Einstein's theories were unprovable at the time he postulated them and 100 years later......there still remain some to be proven?
As far as I know.......none of his theories was subsequently disproven?**
If an audiophile, not a scientist, has repeatable subjective evidence that a phenomena exists, should he postulate a thesis and look for scientific proof before experimenting with this phenomena, discussing it, and assuming it exists?
I think not. It's not his job. His goal is to manipulate the sound of his system and he has subjective evidence to support results. If someone else questions the existence of said phenomena and says it doesn't exist, perhaps this will lead to understanding what is really going on, or not, but requiring an audiophile to postulate a theory and offer proof of a phenomena is absurd.
Regards, |
Henry, You misunderstand me. I really don't give a shit. I am not hyperventilating, and yes, your angry tirades (and one response of mine which was written in anger), in lieu of what could be an interesting back and forth discussion, and your total lack of introspection and self-doubt are indeed "comedic".
I do think there could be some merit in minimizing the plinth (but not eliminating it entirely) for direct-drive, and I do think that a separate arm pod might be a way to go once one has done that, but I would advocate some definitive linkage between arm pod and mini-plinth.
If you don't believe that your shelf can vibrate differentially according to location, take a stethoscope and move it around the surface of your shelf while you wiggle it or tap on it. You will find not only that you can hear the tapping through the stethoscope (not surprisingly) but also that the intensity of the sound will vary from one point to another on the shelf. Where the intensity is minimal, that is a node or close to a node.
Considering the greater scheme of things, I will quote Humphrey Bogart in "Casablanca", this issue does not amount to a "hill of beans". |
Hi Halcro,
I don't know if this is on point, but I am currently experimenting with a type of plinth. My reasoning is simple.
I noticed that using the Precision Pneumatic Footers directly beneath the naked SP10 greatly improves its performance (here, I use the term 'improve' to denote an increased ability to deliver more detail from vinyl) and I have reasoned that this occurs because this approach removes returning vibration that affects all grounded components. This use of footers seems to me to be the greatest aspect of the TT set up that was originally suggested to me by Raul.
Well, my thinking is that the improvement in grounding (or the limitations of its impact through pneumatic intervention) might be able to do a similar job on the tonearm. Hence, I decided to build a floating plinth that will couple tonearm and TT in a potentially optimised way. For me, if it improves the subsequent analogue performance, the case for a plinth (albeit, a floating one) is proven. If it performs at a lower level, the case for a totally decoupled tonearm and TT is proven: at least to my satisfaction.
I should reiterate that I am wholly in the camp of decoupled set ups and that I am currently enjoying a level of analogue that I have simply never experienced before. Still, an open mind leads me to want to settle this matter to my own satisfaction and I recall that that was all that was being asked of the plinth-free and decoupling sceptics. Surely, at the end of the day, music lovers are the real winners if either solution is found to be the better option under equivalent conditions.
As always... |
I can recommend floating the motor/platter in Jello. Dont knock it until you have tried it.
I found raspberry rather nice under the platter, but preferred melon fusion under the arm ( its a unipivot so it has eccentric taste ). My only concern is that I felt wild cherry opened up the bottom end on hard rock, but have settled for the more rounded and harmonically complete raspberry.
For my vintage Tannoys I found feather and down pillows fluffed up the sound just right. The trick is to place them asymmetrically to break up unwanted resonances.
For the amps, hydrogel works a treat. I used breast implants for a full and ripe sound. If you want the best the Tibreeze brand are excellent. These have a titanium coating but were discontinued in 2004 and are hard to find.
I'm still working on the cable solution at the moment. |
I'm still working on the cable solution at the moment My personal choice for isolation from ground hum is using cold coins below them. Best sound is from Krugerrands, 3 coins stacked, US Gold $ is next best, I can imagine that they have similar results below Direct Drives. YMMW of course |
Hi Dgob,
Unless you have the turntable and armpods located on a solid wall-hung shelf.....structure-borne feedback is likely to be a problem.
Every suspended floor (even concrete ones) will suffer from this to some extent.
If I had to locate my TT on a floor-mounted rack....I would ensure that it was on an isolating platform like a Vibraplane of Minus K. Not sure about Dover's Jello however :-)
Your 'floating' plinth idea sounds like an attempt at similar isolation.
It should work to some degree depending on the severity of your structure-borne feedback problem?
Please let us know how you go with it?
Regards |
Halcro -
Have to concur with the wall hung shelf. This is one of the best bang for the buck upgrades for TT's of all persuasions in my view and well worth the time and effort. Biggest difference I noticed was a cleaner and more transparent bottom end. |
Dover, This is one of the best bang for the buck upgrades for TT's of all persuasions in my view and well worth the time and effort. Amen. The audiophiles I really feel sorry for are those who live in modern high-rise apartment buildings like those in Singapore, Hong Kong, China and Australia. Many of these are built using thin prestressed concrete slabs as the floors. Being thin and 'stressed'.....these floors are similar to trampolines and are continually in a state of motion. If you put electronic instruments at various locations on these floors.....you can actually hear them 'singing' although most of the 'singing' is sub-sonic. To make matters even worse........the dividing walls of these apartments are of often lightweight soundproof construction supported not on the wall below......but on the flexing thin prestressed slab. This means that a wall-mounted shelf will be afflicted with the same structure-borne feedback issues as the floor itself? |
Lew,
What you are hearing when you 'tap' on the shelf.....is the effect of the structural stresses within the shelf.
These stresses differ throughout any material depending on methods of support, locations of maximum and minimum bending moments, locations of maximum and minimum shear stresses and locations of all the various deflection points.
These stresses will also differ (in the same location) throughout the DEPTH of the material....normally compressive stresses at the surface, changing to tensile stresses on the bottom (reverse these for a cantilever).
These stresses will normally not affect the material's reaction to air-borne sound transmission.....most waves reflected or passing through.
Tapping a shelf to test for air-borne acoustic performance is similar to the infamous 'tap-test' employed on turntable plinths by some incompetent reviewers.
I liken it to the analogy of tapping on one's head to test for hearing ability? :-)
Regards...and peace |
Thanks Halcro,
And I will of course feedback on my findings. I think the grounding issue really is a major one, despite my use of wall shelf mounting and experimentation with a number of platforms and methods of isolation. Walls rarely seem as neutral to vibration as I would wish and even wall mounting carries detectable vibrations - listening through my system within a fairly solid 19th Century English home. Along with decoupling tonearm and TT (arm-tower/pod), the use of pneumatic footers was (as I suggested) the most marked improvement to the quality of analogue reproduction in my experience: quality of system, hearing sensitivity and expectations not withstanding. That this is the case is simply beyond doubt for me and so my only questions are:
1. Does the decoupled arm/TT really offer the ultimate feasible set up? and
2. Will pneumatic decoupling of a coupled (or, 'plinth based') arm/TT from the grounding/platform really offer the ultimate feasible set up?
That's what I'll be looking into in a suitably empirical way and that's really all that I'll be able to report back on. What others choose to make of that or 'believe' will obviously remain beyond my compass.
As always... |
I should just add that not all pneumatic supports offer the same degree of isolation and that my most positive experiences relate using to the Audio Technica AT616 Precision Pneumatic Footers in particular. |
Dear Lewm: ++++++ " With the big Micro Seiki's, and since we are all about building new or modifying original products to suit our beliefs and desires, isn't is possible to get around their perceived problems with the armboard mount by using (i) an outboard armpod, or (ii) a modification of the original cantilevered design? Since those tables reportedly have many virtues (never heard one myself), wouldn't this be worth the effort? " +++++
I don't think is worth the effort because the MS RX-5000/8000 has more defects than virtues on design, IMHO is a faulty TT design and other that good lokking because the shiny weigthy golden platters there is nothing to admire but its marketing.
The design comes with out any TT isolation for external internal resonances/vibrations, anything goes and stay inside degrading the audio signal. The heavy platters ring like a bell, MS choosed to seat the cantilevered arm boards exactly at the plinth footers where these footers has no isolation and everything is transmited to those arm boards, the motor came from Matushita but the control circuit not only has poor parts but not a good design.
I bought mine because I was a newbie/roockie with the MS TTs that have behind an unjustified fame but we audiophiles are " believers ".
Today I really don't use it any more, I learned on those MS TTs.
Other persons " die for it ", well they like the MS distortions: not me any more.
Regards and enjoy the music,
R. |
Dear Raul, What you write makes perfect sense. I note that most of the MS users have modified their tables to get to where they are happy with it. Along those lines, I would have thought that an outboard arm pod would at least defeat that very real issue you cite about mounting of the OEM arm boards. On top of that, I noticed that some guys use thick mats of various kinds, and other devices, to reduce platter ringing. Further, many use more modern motors, as even the real diehards agree that the MS motors are not so great. By the time one is finished, not much is as original. But I cannot criticize the result, because I never heard one.
One might say that we Lenco users do the same thing; many factory parts are typically discarded and replaced in a well tweaked Lenco L75, but we start with a $300-turntable that is fundamentally sound, not a $5000 (and up) one. |
Dear Lew, There are huge differences among people regarding
the 'force'of their imagination. From your writings one can
deduce that you can imagine every single component without
any experience with the 'thing in casu'. Why then do you need
so many TT's, arms ,carts, speakers, amps., etc.,etc.?
Regards,
|
Dear Henry, Re your last post. First, can we be clear that I am NOT talking about air-borne vibrations? You keep going back to that in order to debunk something or other that I've written, and I keep reiterating that I am not so concerned with that phenomenon, because any audiophile with sense will have arranged his or her equipment so as to avoid or mitigate this potential problem.
Second, I completely share your doubts about the efficacy of tapping on a shelf to assess its goodness as a shelf. But in order to assess how a shelf does react to mechanical energy, entering from the support structure, from the floor, from the whole house shaking because a heavy truck is passing by outside, etc, or even downward into the shelf from turntable motor vibrations, any of which phenomena can set it into vibrating, tapping is as good as any other way to do it. The only purpose for the tapping is to be able to locate the nodes, and to prove they do exist, where the shelf essentially does not move. (As noted, you need a stethoscope for this.) My whole point was about the fact that the shelf will vibrate or resonate at a certain frequency, depending upon materials, mass, etc, and that at that frequency, the shelf does not physically move in the same way everywhere on its surface. There will be minima and maxima of movement. This was my argument regarding the pitfalls of using an outboard arm pod. And for the reason just described, a shelf makes a rather poor plinth. (You COULD use a 1000-lb block of stone, as is done for electron microscopes and other very motion sensitive instruments; I admit that very high mass and using non-resonant materials are ways to approach this problem.) I thought it was a reasonable thing to discuss, but it seemed to anger you instead. Encoding music into wiggles in a piece of vinyl and then converting mechanical energy of motion induced by the grooves into high quality audio is really a primitive notion; there are no perfect ways to do it.
By the way, I re-read your original post. Wouldn't you say that declaring the cartridge to be the center of the vinyl universe is more akin to the Ptolemaic view of the actual universe than to the Copernican one? And did you know that Copernicus merely revived an idea of the ancient Greeks about a heliocentric universe? (I did not know that; did some further reading.)
Dear Nicola, As is sometimes the case, I cannot tell whether you are mocking me or paying me a compliment. But can you please give me a specific example to prove your point, if you are serious? This thread is really about ideas, so I am offering ideas. I usually try to admit it,when something I write is based on hypothesis or a thought experiment, rather than direct experience. |
Well,dear Lew, I am of course not serieus. I was however in my youht when I thought that the philosphers are the guys with ideas and even ideas about ideas. One need to start somewhere so the ideas of my first philosopher were such that I thought that every single sentence was, without any question, true. This wonder happened in the same way with my second philosopher and also the third but by this one there was a problem. According to him the two 'earlier' philosopher were in total disagreement with eacht other and
even contradictory regarding nearly every subject matter.
Not sure if because of Freud or the mother nature who provided us (hopefully) with some defense mechanism I decided that 'all' philosopher are a kind of magician with words with the difference that they do not perform their act before some audience but write books instead. This way I was able to keep my own selfestime intact and also decided to become a lawyer. There are some of them which are called 'the best attorney' whom only few can afford. No philosopher ,even Popper, were able to earn this kind of money. But as is so often the case I also neither become 'aviator' nor attorney.
BTW with your imagination can you not reconsile the two: the mocking and the compliments? I admire you really but also like to tease you. Is this 'not done' according to some of Kantian imperatives?
Regards, |
|
ah, I see all the great champions in this analog world are coming together. welcome back gentlemen. yes it is worth talking about armpods and the possibility of exchanging arms quickly. I would miss my universal original Micro Seiki armboards so much that I even mounted one on my EMT. I now learned that Raul is not using his MS turnable anymore. No wonder - No system change on TTs in 10 years, you might feel like in a storage room of old unused audio equipment. Don't laugh, I have seen this sometimes. People keep their units but only use one TT all the time. They have many arms but use only one. Why not?
If this might enable the owner to have a profound knowledge on comparing TTs and arms and also assess the quality of armboards in certain environments I doubt. |
Dear Nicola, We're good. In the vernacular of Italian-Americans, "fuhgeddaboudit". Same goes for Henry, actually. |
Dear Lew, Our 'teasing relationship' started with your beloved Mark Twain , the 'rumour' about his death and my slip of the tongue with guy versus gay . I then just started to write English. With Henry the case was different. I referred to his beloved Australia as 'a developing country' which caused him to refer to me as a 'little man' from a 'little country'. You was then more sportsmanlike then he was. But at present I love you both equally.
Regards, |
Did I really call you a "little man from a little country" Nikola?
Haha............
I must have had a sense of humour in those days?! :-)
Love you too......
Lew?......not so much.....:-) |
Dear Henry, Yes you deed and this is not called 'humour'
but 'belittle' in literally sense. Humouros on the other hand
was Lew's response. I wanted to make him a compliment
but made a typo: 'this Lew is a smart gay'. His answer was:
'the rumour that I am a gay is exaggerated'. He borowed
this phrase from Mark Twain who was suprised to read
in the paper that he passed away: 'the rumour that
I am death is exaggerated'. Aussie humour? You must be joking .
Regards, |
Lewm did you know that Copernicus merely revived an idea of the ancient Greeks about a heliocentric universe Yes: Aristarchos the Samian. Info acquired recently thanks to my kids... Until then, Samos was an island (it still is) and produced very goodwhite wine (muscat, "AOC Samos"). |
To be precise: "Rumors of my death are exaggerated."
Henry, I may start calling you "Hank". |
To be precise: what a niggling correction. According to
Frege the same tought can be expessed in different ways.
Otherwise we would need to surpass computers in exact
repetition of the words sequence. I should not use
quotation marks however. But for the foreigners among
us; what is a Hank?
Regards, |
Hi All,
One of the useful sources that I have found for designing my own (experimental) floating plinth is: http://qualia.webs.com/plinthbuilding.htm.
Although obviously not the last word on the subject it has some useful suggestions that might help other explorers.
As always... |
"Hank" is an apparently American nickname for someone whose given name is "Henry". Thus, the famous baseball player, Henry Aaron, is better known as "Hank Aaron". Now you mention your unfamiliarity with "Hank", I am not sure that they use it as a nickname in Oz, either. By the way, there is nothing pejorative about it. Henry/Hank is probably off somewhere with a pint of Foster's, ever since Adam Scott won the Masters. One of my Australian friends emailed to me that he was in tears over this victory, the first for an Aussie. |
Correct Lew, my father's name was Henry and everyone called him Hank. |
Hi Dgob,
Unfortunately your Link does not lead to the page you suggest?
Are you able to re-load? |
'Hank' is purely an American epithet for 'Henry'.
Whilst I would have preferred it whilst growing up.......in Australia, it simply doesn't exist.
Although we do have a certain eccentricity in knowing the famous actor Tom Henrys who appeared in Sleepless in Seattle? |
Hi Halcro,
I don't understand why it wont load. However, if you google Audio Qualia you can find the relevant plinth related sections. I've also found some use in 'The Practising Scientist's Handbook', written and compiled by Alfred J. Moses (Van Nostrand Reinhold Company, New York, 1978) as cited at http://www.soundfountain.com/amb/sp10plinth.html.
Some explorers tend to emphasise that plinths were seen as a 'necessity' in order to keep the motor and innards of old TT's in place: as well as offering aesthetic advantages. With many of our models and concerns, this is obviously not a requirement and this (along with my own extending listening to a decoupled, plinth-less set up) leads me to suspect that the pneumatic footers and stand-alone arm tower for the Technics SP10 might be the optimum option - from a performance point of view. Anyway, I will give the plinth option my best efforts in order to adequately clarify the/any performance differences.
As always... |
Sorry,
Just to note that the use of pneumatic footers has its antecedence in the Mitch Cotter approach that found such acclaim decades ago. However, we're adding the potential benefits of the decoupled tonearm - in our current plinth-less and decoupled set ups.
Very little seems new regarding mechanical management (the use of pneumatic footers and magnetic footers aside) but new developments regarding materials (Panzerholz, aluminium/acrylic sandwiches, viscoelastic materials and the like) do offer interesting possibilities to such old discoveries. But I begin to ramble.
As always... |
Dgob, Just as the peritoneum was once seen as a necessity to keep the stomach, spleen, liver, intestines in their proper place. I am keeping mine.
Henry, Good one, re "Tom Henrys". |
Dgob: your link has an errant period at the end of the url; delete it and the page loads. |
The Mitch Cotter that I'm familiar with had a sprung suspension just like a Linn, only more springs and controlled better with foam inserts, no pneumatics involved.
The main thrust of his design was to remove all the extraneous crap from the direct drive ( motor covers and controls etc ) which removed resonances, and the use of an extremely rigid and inert aluminium/polymer laminated chassis to bolt BOTH the arm and DD motor drive.
Some great ideas embodied in that design in terms of energy control and maintaining a closed rigid loop between platter and arm.
|
Banquo363,
Many thanks
As always... |
Dover,
Yes, and thanks for helping with my ongoing considerations, research and experimentations. Of course, Cotter's floating (aluminium/polymer laminate) baseplate and attached platter was decoupled from the main chassis. My point was that the polymer fillers and springs that sat against the baseplate served a similar function (albeit in a far less efficient way) to the pneumatic footers against the bottom of the SP10 regarding resonance control.
I didn't discuss the dismantled motor that many have already considered regarding Kenata's design etc. I do feel that the potential gains of that aspect of Cotter's approach are accommodated in a simpler way by the already noted plinth-less and pneumatic support approach, however.
Much more reflection and experimentation to be had but progress seems promising.
As always... |
Lewm,
All too confusing an analogy for me. The SP10's peritoneum would surely be the motor case rather than the additional plinth!
Designs seem to vary but operational excellence needs to be assessed in the light of the object and function under consideration: 'just as' arthropods function well with an exoskeleton but I function best 'keeping mine' internal.
I'll just press on with my efforts to discover how the SP10 and its associates function best. Who knows, when all is said and done, I could end up sharing your anatomically grounded perspective. Time will tell.
As always... |
Dgob, Sometimes I go for humor ahead of substance. Just kidding. We all know where I stand on the issue of plinths. I have done the work to reach my conclusions, so I feel ok as regards my own preferences and my own system. However, I am beginning to think about an inert plinth that provides a lot of mass mostly under the platter/motor assembly, so there is a minimal "deck" extending out around the platter periphery. Then a pod for mounting the tonearm, like the ones some of the guys have built, that would be firmly mated via a structural member, back to the main plinth. A few commercial products are built that way. I do not back off my contention that a closed loop connection between the tonearm bearings and the tt bearings is desirable, as Dover mentioned. |
Lewm,
It sounds interesting and I'd be interested to hear about the outcome of your experiment. The closed loop arrangement is precisely what I'm trying to test while optimising the isolation in light of other decoupled approaches.
Experientially, (as everyone is probably aware) I am convinced by the performance of an SP10 on pneumatic footers with a decoupled tonearm arrangement: the sound is exceptionally good and greatly exceeds all of my prior analogue experiences. However, I am really only interested in obtaining the optimum performance from my gear and that could very well lead me to share your beliefs - even though I remain quite dubious. I will give it my best shot and see what that brings.
As always... |
Lewm,
And the humour was appreciated.
As always... |
Lew, you just described what I have evolved to with my own design. Hopefully now my local woodworker can turn it out for me. |
2 1/2 years since the last contribution and yet nearly 1.3 million views...😎 In the time since my first enthusiastic proclamation, I realise I may have been a little cavalier in my concentration on the arm-pods at the expense of the platter/motor itself. As most of us have realised after decades in audio......EVERYTHING matters.... I initially designed and had made, the solid bronze arm-pods and merely placed the platter/motor on tiptoes http://i.imgur.com/Xp97BF8.jpgWhilst the sound produced by this arrangement seemed to prove my thesis....others looked to improve on my platter support http://i.imgur.com/sPdkMWn.jpghttp://i.imgur.com/8BTXLIL.jpgRealising that the flimsy metal shroud protecting the motor unit was able to 'flex' as the platter spun....I designed a stainless steel cradle to more rigidly hold the turntable http://i.imgur.com/UuEyECm.jpghttp://i.imgur.com/Ui6trXd.jpgThis was an immediate improvement and I discovered that the Victor DD decks actually sounded better 'nude', without their protective metal shroud. In the intervening years I became a little frustrated at the tendency for this lightweight 'cradle' to be moved whenever I re-aligned a new cartridge (which was rather often 👅). The arm-pods at around 11Kg each, would NEVER shift on their spiked feet. I needed a 'cradle' with more mass, and thus was born the polished granite cylinder http://i.imgur.com/S97uGns.jpghttp://i.imgur.com/qUyVNA2.jpgThis change was as much a revelation as the bronze arm-pods.... It seems that even the SS cradle was able to 'twist' under the constant centrifugal forces of the spinning platter and this resulted in a loss of ultimate transparency and lower register control. No wonder the latest 'rave' turntable (Kronos) utilises counter rotating platters to neutralise this twisting force. https://s-media-cache-ak0.pinimg.com/736x/62/64/dd/6264dd2057a9132a141c8cfda552102d.jpgI feel a little foolish to have overlooked what must have appeared obvious to many for all these years....but the lessons have been learned. Not only must the arm-pods be massive and immovable....the platter/motor must also be held in a vice-like grip. Mass is one method of achieving this but there are obviously others....... A few problems were discovered during this last design exercise and they may be peculiar only to the Victor decks...❓ Whilst the 'nude' motor unit sounded better in my system....when I mounted it in the first granite cylinder http://i.imgur.com/xIGWxmM.jpgelectrical feedback of the 50/60Hz became apparent with the two tone-arms which were not in the 'normal' platter/arm universal relationship. http://i.imgur.com/ieD1q6s.jpgHere you can see the DV507/II tonearm/cartridge passing directly over the motor transformer. This was the most affected tonearm. The solution was to screw on the metal shroud which apart from protecting the delicate electronics and circuitry....acts as a Faraday Cage to block the RFI/EMI for the cartridge http://i.imgur.com/UAEMFj7.jpgAnother important cure for this feedback problem is to connect the ground wire from the chassis to the preamp. With all systems go.....time to sit back with a good Scotch and enjoy the fruits of my journey...🍹🎼 |
halcro
Another important cure for this feedback problem is to connect the ground wire from the chassis to the preamp. Are you referring to the ground added to the pcb board or the external cage connection point? |
Are you referring to the ground added to the pcb board or the external cage connection point?
The ground wire attached to the PCB did nothing to mitigate the RFI/EMI interference. With the Faraday Shield (metal shroud) in place and the ground wire attached.....the problem appears to have vanished. I'm not electronically/electrically savvy so can only report the effects.....it appears that the Faraday Shield 'absorbs' the electrical energy emanating from all the electronics (particularly the power supply) and the ground wire dissipates it from the screen. I used to keep the motor 'powered on' (but not operating) when mounted in the SS cradle as it tended to sound better than fully 'cold'. Within the constricted enclosure of the granite cylinder.....I found that the build-up of electrical energy if the motor was left on (without the Faraday Cage) totally destroyed the sound of the turntable rendering it unlistenable. As a precaution to the bouncing around of this electrical energy off the reflective granite enclosure.....I lined it with cork sheeting in the latest version to try some absorption.....🤔 |
Inna, Despite the fact that Freud is dead we all(?) know that he would say
something about our 3 ego's. I myself fear the ''it'' the most. The other two
can impossible explain the number of my carts and arms.
|
It's seven years since I began the Nude
Turntable Project and thus also formulated "The Copernican View of
the Turntable System".
In that time I have learned a great deal through practical experimentation and
listening.
The lessons are many but the most significant one I believe, is this:-
- Isolated
armpods around a 'nude' turntable is one of the most difficult (and
problem-frought) solutions to the turntable design imaginable...
There are only two advantages I believe, for this solution:-
- Ability
to easily adjust geometry for every (and any) tonearm
- Potentially
better sound
The pitfalls are numerous:-
- Stability
of the turntable
- Isolation
of the turntable
- Levelling
of the turntable
- Stability
of each armpod
- Isolation
of each armpod
- Levelling
of each armpod
- Maintenance
of the geometric relationships
- Elimination
of ground-loop hums
- Elimination
of EMI/RFI interference
- Cost
The fact that it has taken me seven years to fully resolve
all these issues (and the multitude levelling processes are still not perfect)
should be enough to discourage all but the foolhardy from following....
HERE is the final resolution
of my Copernican Nude Turntable...
You will notice that the whole assemblage now sits on a Herzan TS140 Active Isolation
Platform which weighs 28.5Kg(62.8lbs).
This platform in turn sits on a propped and cantilevered 33mm wall shelf made
of laminated stressed-skin MDF.
The circular blue plastic discs under the spiked footers are poker chips which
were needed to prevent a ground-loop hum caused by all the armpod and turntable
metalwork, conducting through the Herzan aluminium top-plate to the electronics
below.
These poker chips are Superglued to the Herzan aluminium top-plate to prevent
movement and 'lock' the overall geometry in place.
The Herzan provides sub-hertz active vibration isolation in all six degrees of
freedom.
Performance Details:
- Active
vibration isolation from 0.7 – 1,000 Hz
- Passive
vibration isolation from 1,000 Hz and beyond
- 90%
vibration isolation at 3.5 Hz
- 99%
vibration isolation at 10 Hz
- 99.9%
vibration isolation at 20 Hz and beyond
- Up
to 55 dB of vibration reduction beyond 20 Hz
This Active Isolation Platform has highlighted a major
weakness in the Copernican philosophy....
Because the armpods are separated from the turntable motor, they are all
subjected to the maximum Structure-Borne Acoustic feedback experienced by the
supporting floor/shelf/rack system.
With a 'normally' designed turntable.....the
tonearm mounting points are attached to the turntable's plinth and are thus
'shielded' from structure-borne feedback by the turntable's own isolation
footers and mass/material of the plinth design. The levelling of the arm
supports is also integrated with that of the plinth.
Here is a readout of the vibrations experienced by the Herzan with the Isolation 'OFF' and the
turntable/arm at REST.
The top line is vibration in the vertical plane and there are two directions of
horizontal vibrations below.
These vibrations are purely Structure-Borne Sound Transmission caused by the
flexural stresses in the supporting shelving material and are entirely ultra
low-frequency (2-10Hz). They are there ALL THE TIME....
These ultra-low frequencies can pass through and affect ALL materials
regardless of their mass or densities, and they are not successfully absorbed
or reflected by normal isolation stands, footers or springs.
Only specialised stands designed for applications such as electron microscopes
(able to provide isolation down to 2Hz or below) can prevent these damaging
frequencies affecting the turntable/platter/arm/cartridge interface.
Here is a readout with the Isolation 'ON' and the turntable at REST.
You can see how the Herzan has 'actively' absorbed and nullified these ultra
low-frequency vibrations and prevented them entering the turntable system.
All the following readouts contain vibrations of higher frequencies (mostly
above 1000Hz) which are able to be absorbed, reflected or dissipated (to a
degree) within the normal provinces of footers, stands, isolation devices and
depending on design....within the plinth, platter, feet and mass of the
particular turntable.
Here is a readout with the Isolation 'OFF' and the turntable
REVOLVING.
Here is a readout with the Isolation 'ON' and the turntable
REVOLVING.
Here is a readout with the Isolation 'OFF' and MUSIC PLAYING.
Here is a readout with the Isolation 'ON' and MUSIC PLAYING.
The Herzan has been integrated in my system for 6 months now, and not only is it the final 'piece' of the jigsaw for the 'Copernican'
puzzle.....but it singularly is the most significant contributor to the elimination
of 'distortions' and the elevation of sound quality that I have experienced in 40 years of
audio.
It must also have been a revelation to Frank Kuzma (who shares the remote armpod
design philosophy for his TOTL turntable) as in May 2017 at the Munich
High End Show he demonstrated a Herzan
(Table Stable) as a recommended part of his system. But as I mentioned....the Herzan is the last piece of the 'Copernican' jigsaw. Some of the initial 'pieces' have proven to be naive....for instance, originally I had the Victor motor unit (with its metal shroud) supported directly on Tiptoes. Whilst the sound was still good....I was disturbed that there might be movement of the turntable with this primitive supporting method. I thus designed a skeletal stainless steel cradle which I thought would prevent any possible movement. It didn't....and in the process I had removed the motor's original perforated metal shroud. This shroud (it turns out) was acting as a Faraday Shield (with ground wire attached) in protecting the platter from the motor-induced RFI/EMI which now beset the installation. It wasn't until I designed a new 8.1Kg (18lb) polished granite plinth, that I was able to reinstate the metal shroud (complete with ground wire) onto the motor unit and eliminate - Movement
- Ground-loop hum
- EMI/RFI problems
Now all of you are shaking your heads at my stupidity in not having a solid, heavy plinth as the 'de facto' starting position, knowing how many Threads there are extolling the virtues of heavier and heavier Panzerholz, slate, granite and lead-lined plinths..... I'm not sure if heavier and heavier is necessarily better and better.....but I may be wrong 🤔. In the current design, 8.1Kg of granite is the best I can do and I think it's adequate.....🤗 It's only necessary IMO, for the cradle/plinth to be heavy enough to prevent the constant centrifugal forces of the revolving platter being able to induce 'movement'. For Belt-Drive or Idler designs...I can imagine these forces (and thus mass of plinth necessary) to be greater. One thing I DID get right at the beginning, is the size and weight of the 11Kg (24lb) solid cast bronze armpods which surround the motor unit. These are immovable monoliths and are successful in keeping each arm motionless and rigidly clasped whilst providing total immunity from motor/plinth/platter noise and vibrations. This isolation of the arm-mount is a known phenomenon which Continuum tackled in their Caliburn turntable, by suspending and isolating with magnets, the tonearm mounting plate from the plinth proper. There are other isolated armpod designs which use lighter, taller and flimsier pods which, apart from defeating the purpose of the 'Copernican' concept....may be susceptible to accidental and/or vibrational movement. Those designs I don't accept, as conforming to the principle 😱. There are detractors of the isolated armpod solution (and some of them have been prominent in their opposition here, on this Thread). The theory behind their opposition is valid.....rigid connectivity between the platter spindle and the tonearm pivot is a 'sine qua non'. I agree with them..... These theorists usually share two traits:- - They have never had a functioning isolated pod in their home system
- They refuse to accept that the shelf/rack/stand/base on which the turntable and armpods sit, together with 'gravity' are sufficient to maintain a 'rigid' enough connection
They are entitled to their views and I am not about changing these... I however DO have a functioning isolated pod system in my home (alongside a normal 'all-in-one' turntable) and believe that they are wrong.
If the turntable 'base' and isolated armpods are sufficiently heavy, gravity is indeed enough (as it is with all the buildings in the world) to RIGIDLY maintain the required geometry without the detrimental effects of transmitted vibrations from the motor/belt, bearing and plinth to the tonearm. There are some notable advocates and adoptees of the 'Copernican' theory:- I don't believe that anyone could call these designers and manufacturers (especially Frank Kuzma and A.J.Conti) fools...... So here I am......seven years later with a turntable system I can honestly attest, is the best I have heard. And I have heard most of the acknowledged 'greatest' of all time....... Now I don't positively know whether it's because of the isolated armpods, the superb Victor DD motor unit or the Sub-Hz Active Herzan Isolation Stand that the results are so good....? It's most likely a combination of all three 🤗 Would I recommend others go down this same path....? In hindsight....only if an Active Isolation Stand was a 'sine qua non'.....and this elevates the cost greatly. But consider this....even WITHOUT the Active Isolation Stand....the sound quality is capable of exceeding that of 'Digital' by a large margin 👅 My turntable system (complete with admittedly expensive tonearms) is in the realm of US$30,000 (with the Herzan close to half the total). Expensive compared with the average turntable...yet not outrageous when compared to 'Uber Decks' like the Caliburn, VPI Direct, Kronos, Walker Proscenium, SME 30/2 or any of the 'Copernican' decks mentioned above. I think I'm finally done and am happy to offer help/advice to anyone brave or crazy enough to venture down the same path.....😎🎶 Happy listening.....
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All the following readouts contain vibrations of higher frequencies (mostly above 1000Hz) which are able to be absorbed, reflected or dissipated (to a degree) within the normal provinces of footers, stands, isolation devices and depending on design....within the plinth, platter, feet and mass of the particular turntable.
Here is a readout with the Isolation 'OFF' and the turntable REVOLVING.
Here is a readout with the Isolation 'ON' and the turntable REVOLVING.
Here is a readout with the Isolation 'OFF' and MUSIC PLAYING.
Here is a readout with the Isolation 'ON' and MUSIC PLAYING.
Halcro, If I look at the Herzan readouts with and without the music playing, the correction is different. This would appear to show that the Herzan is effectively modifying the music signal playback due to the vibrations of the stylus by imparting a corrective response that has taken into account stylus vibration generated into the platter/TT. Thus the measurement of the groove by the stylus is no longer accurate because the Herzan is responding to the music and thus polluting the signal.. Could you give some consideration and response, thanks. Dover |
