fwiw, I tested the cover grounded vs ungrounded and never heard a difference. I just put the ti shield there on a whim, because I had it and said what the hell. I also have cut pieces of it between the motor cover and the platter. Again: what the hell.
Your word of caution, Lewm, is duly noted. I'm about 2 weeks in and I've not noticed any adverse effects. Fingers crossed. But the differences I'm hearing don't seem to be the type that would result in future unhappiness. For example, it's not as if I'm getting 'fuller bass' or 'extended highs' or a 'sweeter midrange', all of which can potentially lead to dissatisfaction in the long run.
I forgot to mention that pantsing has not changed the start up speed (as Halcro noted on his): mine still very occasionally starts at 33.32. As I noted before, I think it's due, in my case, to using a duster that puts pressure on the record as it gets up to speed. I've not ever noticed it start at 33.32 when I do not dust. |
I agree with all that the metal chassis is a sonic problem and removing it entirely might be a good idea. I am going to try it. I had already come to the conclusion that the "pants" on the DP80 ought also to be removed, but first I am going to try damping the DP80 chassis with two thick strong rubber bands that were gifted to me.
The TI Shield won't do anything down there, especially since it is apparently not grounded. To ground it, just solder a bare wire to it anywhere on its surface and run that wire to tt ground. But in that position, it can't be of much help regardless.
The only downside to de-pants-ing is that it removes the RFI shielding afforded by the ferrous pants. Thus I would be cautious not to interpret changes you may hear in the sound solely to removal of resonances. There could be some RFI contamination via the cartridge. Sometimes any change to the sound that is new is also thought to be good, until you listen for a long while and realize you are fatigued by something irritating in the new sound. I hope this is not an issue, however. |
I cleaned out my bearing as well. For no particular reason other than that Gary made it sound easy--and it was, sort of. My oil was also brown and unsightly. I used Mobil 1 20w-50 motorcycle oil as replacement. One thing to note for those considering doing this is that the screw used to access the bearing is also used to raise and lower the platter. As I found out, the platter needs to be at a particular level to avoid scraping and/or locking. It's not trivial to find the correct level and it's a serious pain to handle the unit and flipping it right side up to check whether one has found the sweet spot. So: I pantsed a la Halcro my Victor a couple of week's back. Before I did so, I listened intently to 3 album sides and then subsequently compared the differences. I changed nothing else. Like Ecir38, I had suspected that the differences Halcro found were due to his new supporting system and not so much to the absence of the metal cover. I'm here to report that my suspicions, at least as they pertain to my Victor, are wholly unfounded. With respect to all 3 album sides I used the changes were the same: the character of the instruments including voice became more nuanced (microdynamics?) and impactful (in terms of scale but not loudness, if that makes sense) than they were. I can better hear the music as a whole. For example, the first movement of Mahler's 9th can sound like a convoluted mess if the musical 'line' is lost. After the pantsing, I could better follow along because certain passages that were relatively obscure suddenly came to life and became 'ready to hand'. Unfortunately for me, my system still cannot reproduce the double bassess accurately--but that's another issue. Ry Cooder's guitar work in 'Into the Purple Valley' has never been as nuanced and transparent. And Paul Desmond's sax in Brubeck's 'Gone with the Wind' has never sounded so right. I am pointing out only the most dramatic cases; there are many more subtle ones. One other difference to note is that everything seems quieter. I don't mean the noise floor has dropped, but rather that I seem to want to turn the volume up nowadays. I think the desire is connected to the decrease in distortions (trademark, Raul) that I was subjected to prior. One potential caveat: I recently changed my headshell leads to Oyaide silver. I had them in during the initial unpantsed audition, but they might not have been fully burned in (if you believe in that sort of thing). I personally don't believe the differences I heard can be accounted for by the leads. fyi: the copper looking thing underneath the victor is a Texas Instruments Shield. I had planned to use it underneath my platter mat but it refused to lay flat--that and I don't currently use anything but a piece of pigskin. Yet another benefit of listening to Halcro. |
I am all for "education and hobby fun", dagnabbit!
The Denon DP80 bearing is also supposed to be "forever", so I've done nothing to the bearing in my DP80, as well. The fact that your bearing fluid was brown indicates it probably was a good idea to change it. However, I personally would be leery of over- or under-tightening that slot-head screw that forms the seal at the bottom of the bearing well (in the TT101). Anyway, you got away with it. The thrust plate might be teflon, probably not "soft plastic".
Did you mean to imply that you needed to access the innards of the bearing in order to install rubber/steel grommets between the motor and the frame? I am not sure why, if so. |
Lewm, the fluid was brown and had particulates in it. The bearing looked fine, the plate is soft white plastic so was dented by the bearing but otherwise fine. I do not recommend opening the bearing up unless you have detected a problem. I thought I had made that point in my narrative. But it isn't a real issue if you do it right, and it also enabled me to put rubber/steel grommets between the motor and the frame. All for education and hobby-fun.
Gary |
Aigenga,
In the TT101 Service Manual it explicitly states that the bearing needs no service, which would include periodic lubrication. Bill Thalmann also strongly advised against trying to "lubricate" it. You may fairly respond, and I would agree, that Victor probably did not envision a 30-year lifespan for the product. Therefore, at this point in history, some attention to the bearing may be merited. What did you see when you first accessed the bearing? What was the condition of the lubricant, the bearing, the thrust plate? I am just curious; I don't think what you did was necessarily "wrong" in any way. What lubricant did you use when you serviced your bearing? Thanks.
Halcro,
I think what you have now is a "plinth" by my own definition. Many if not most of the best belt-drive turntables are built with solid, heavy bases that do not afford an open deck surrounding the plane subjacent to the platter; I always thought that was a good idea, as is yours. If I had it to do over, I might have fashioned my own slate and wood plinths in a more minimalist way, but I am not about to do it over. By the way, my Lenco most of all benefits from its dense slate plinth. Why re-open the argument? |
Halcro.
We are both blessed with having music rooms that have concrete floors sitting on mother earth.
My definition of a plinth is likely a little wider than yours. To me it is.. "the structure that maintains accurate dimensional stability between the record surface and the tonearm". I am sure that you will agree that dimensional stability in this area is critical. I have also called this structure a "loop" in an earlier post.
By that definition your very nicely built stainless steel motor support, the shelf(or floor) and the equally nice arm pod are all parts of the plinth.
It would be reasonable to expect a change in the sound, if you were to change the stainless steel support for say a large diameter cardboard tube. Likewise we could expect a change in sound if the arm pod was made from say balsa wood. I suspect that your choice of these materials was based on experience and sound logic.
Since substitution of different materials would likely alter the performance, it can be inferred that your "plinth" does have a sound. |
Richardkrebs, I imagine its possible to define an object into existence to suit ones argument
.but Im not sure where it gets you? To define a plinth as a shelf allows for a rack, a platform and of course the floor to also comply with that definition. It gives us the situation where audio items like power conditioners and DACs and SUTs and preamps and amps are all on plinths? And for those with a REAL turntable plinth on a Minus K stand on a shelf on a rack on a floor
..we have a plinth on a plinth on a plinth on a plinth
..? It would also seem logical that different shelf materials, size, shape, support method, spikes, et el would make a difference. This would only be logical if one could conclusively prove that there was stored energy within the shelf or within the object ON the shelf which REACTED to the materials, size, shape, support method, spikes, et al in a way that affected the motor, bearing, platter, record, stylus, cartridge and arm in a turntable system for example? Despite the availability of accelerometers and other devices designed to measure and quantify vibrational energy and its transfer within materials
..I have seen no scientific evidence to support the many statements made by audiophiles on the nature of vibration draining in regards to turntables
.and any quantification of such? The vast majority of audio systems are supported on the floor of the listening room albeit on racks or stands of some sort. The vast majority of those floors are suspended timber frame or suspended concrete slab
..very few are concrete slab-on-ground. All suspended floors (be they timber, steel or concrete) are under bending stresses of various magnitudes which create low frequency acoustic energy within the structure. This low frequency energy (often resulting in movement) is transferred to the rack/stand/shelf supporting the equipment and results in higher frequency energy transmission and movement which is passed through to the equipment supported thereon. With all this low frequency energy swamping the stands, racks and shelves
it is no wonder that differing methods of support and differing materials all have an effect on the transmission and damping characteristics? But you are mistaken to assume that those who have absolutely no structure-borne feedback will also experience the same phenomena. My floor is a reinforced concrete slab-on-ground topped with polished granite and is totally bereft of any structure-borne sound. My turntables sit on a stressed-skin MDF shelf cantilevered from a masonry structural wall supported on that reinforced concrete slab. The turntables sound identical whether they are sitting directly on the polished granite floor or up on the cantilevered shelf. I have tested many methods of support for the turntables including an additional independent shelf on top of the cantilevered one
.sorbothane feet, Delcrin footers, Stillpoint Ceramic feet, Stillpoint Ultra Minis, ceramic cones, aluminium cones, steel cones, plastic cones, brass spikes, steel spikes and stainless steel spikes. I have placed various materials between cones/spikes and the supporting shelf including metal coins, plastic, cardboard etc
and with all and every variation
..there has been zero change to the sound. When there are no Structure-Borne feedback problems
there is nothing to affect the turntable adversely (other than Air-Borne feedback
..but that is another can of worms). In fact a sure way to determine whether your room suffers from Structure-Borne Feedback is to see if changing the spikes, rack, footers etc results in an audible change? But back to the plinth
Im sure you have much to contribute to a discussion on a real plinth into which a turntable like a DD or Idler may be mounted? :-) |
Halcro.
You are using a plinth.
It is the shelf upon which your TT sits via the spikes you are using.
It would also seem logical that different shelf materials, size, shape, support method, spikes, et el would make a difference. |
I was thinking last night
because Aigengas TT-101 is nude and mounted on a wall-hung shelf like mine
I know exactly what it sounds like?
Same with Banquos nuded Victor.
But I also know what most Raven AC turntables sound like (assuming they are not plagued by uncontrolled Structure-Borne feedback) and Rega Planar 3 turntables and Linns and Caliburns.
And if I was familiar with the big Micro Seiki 5000 and 8000 models
..I would probably know their sound as well?
But I have no clue how a re-plinthed SP-10 Mk2 or Mk3 sounds or how a re-plinthed Lenco, Garrard, Thorens et al would sound and I cant imagine how anyone else can?
If every plinth can sound differently depending on material, sizing, construction, damping, resonance-draining and footers
.how does any example sound like another?
And if they all sound slightly differently
..who decides which is more accurate and how is this decided?
From a purely objective and somewhat logical viewpoint
..if a self-contained turntable like a direct-drive model (and to some extent Idlers) can perform their function without being encapsulated by a plinth
..why is it not reasonable to conclude that any changes to the sound resulting from the addition of a plinth is a colouration
an addition or a deduction or a corruption?
How do the plinth advocates reconcile the fact that no two examples can possibly sound exactly the same? |
Halcro, I am happy for any (if any) role I played in inspiring your creativity. In our crazy hobby, everything matters and often it is impossible to figure out what does what to our precious sound.
Audpulse, Sorry but no pics available on this one. Here is my best info:
1. first why do you want to adjust the thrust plate - is there a problem with how the platter turns? If not then sit back and think about it some more.
2. if you want to go forward keep this in mind: the pressure on the plate is not random, not at all - if you get it wrong the platter either won't turn or it might make it harder for the table to get a grip and get spinning. Which I think might have happened to me.
3. The TT101 has a center screw that is easily visible and accessible from underneath once you remove the bottom can. To do this it is critical that you first remove the platter, then turn the tt upside down onto a bowl that is broad enough to sit stably as you work.
4. The center screw provides the pressure on the thrust plate. It is screwed in to an exact spot - don't forget that. It is also sealed with Loctite or some such sealer which you will need to scrape away and replace when you replace the screw.
5. Once you take out the screw you should replace the oil in the well - about 1/2 ounce will do. I suggest synthetic motor oil. You can wipe it out with a clean cloth. Careful in that there is a loose ball bearing sitting there and you don't want to lose that.
6. Reassembly is just that, but don't forget to seal that screw or your oil will leak out.
I hope that is useful to you. Questions? |
|
Thanks Aigenga..........I knew the looks would not be to everyone's taste....and initially scared me somewhat :-0 But now I think the covered 'guts' look stodgy in comparison. As Ecir said above.......I think it looks "wicked" :-) I really admire the way you have supported your TT-101 on the wall-hung shelf....and its interesting to read about your use of the central 4th spike? I remembered well your 'damping' of the outer metal casing and following your advice, I bought 2 bungy straps on Ebay and wrapped them around the outer casing....without however hearing any differences? It was your reported improvements in damping the outer casing which encouraged me to remove it completely :-) And the improvements have indeed been audible....but how much is due to the removal of the casing or the better supporting steel cradle or the decoupling of the deck from the cradle support....I don't really know? |
Which part interests you - the leveling or the thrust plate adjustment? |
Aigenga wrote---"This excellent support - perfectly leveled (plus I did another adjustment to the height of the bearing thrust plate) has solved all of the start-up problems it was having. It starts immediately and runs at exact speed without hesitation at the push of a button - just as it should".
Is it possible to explain further how this is accomplished and also post some pictures to help a layman like me to fully understand what you have done. |
I haven't been on this site for a while and just caught up with Halcro's brave changes. I admire your "out of the box" thinking, Halcro. I could never feel comfortable looking at the electronic guts hanging out of my TT.
My TT-101 is now seated on a "SolidSteel WS-5" brand wall shelf - which is bolted to a brick wall. This wall shelf is a heavy steel perimeter frame supporting an mdf shelf which is leveled by 4 spikes into the steel frame.
This excellent support - perfectly leveled (plus I did another adjustment to the height of the bearing thrust plate) has solved all of the start-up problems it was having. It starts immediately and runs at exact speed without hesitation at the push of a button - just as it should.
The turntable sits on that mdf shelf using it's original steel can resting on 3 perimeter brass heavy points and a 4th heavy point sitting dead center under the can. That 4th point is a drain for the can and is important even though the can is damped.
I have discussed at length how the can is a major problem and needs extensive damping. Mine is lined with bitumen damping sheets (about 1/4 - 1/3 of the venting holes remain open) and has a heavy rubber strap around the top where it mounts to the structure of the TT. Even though only a fraction of the ventilation holes remain in use there is no heat build up - the can stays cool to the touch after spinning for hours.
I believe that I have reached a stable point and will leave well enough alone. Ella Fitzgerald is scatting in agreement. |
The Gyro testing table had 6 cast iron legs. Five of them were height adjustable with wooden decoupling pads. The sixth leg had no adjustment and it directly coupled with the concrete floor. Interesting gave this more thought. My current version Sp10/Armpod testing TT is different from the Gyro as it is a rigid structure bolted into the base/plinth. No provisions for height or level adjustments. All height and leveling adjustments are done by the three adjustable AT-616 pneumatic footers under the base/plinth. In this case the actual TT system feet are these footers and I use three. As noted earlier the ET2 tonearm has its own leveling system independent of these feet for final leveling. I level the platter as best as possible then the tonearm. My SS legs are acting as supports and are not the actual TT system feet. I would want to keep all four for stability and rigidity. Sounds to me like trying this out means changing out one of the AT-616's for an alpha leg ? The one under the tonearm in the pic ? |
Halcro/Pryso
We are in agreement on the "stability" of 3 feet.
My comments on stability are in the context of draining unwanted energy using single point mechanical grounding. I also assume the tripod is correctly designed for weight distribution to give stability and deal with rotational energy around the central axis. I also assume we are not driving the TT down to the grocery store and we are not in the habit of sitting on it.
Very few surfaces that the gear is mounted on are truly level, and in that context 3 feet will naturally load predictably, whereas with 4 or more feet they will have to be adjusted precisely to provide predictable loads through each foot. This is almost impossible unless you have pressure pads under each foot. The Mana stand manufacturers' recommended set up procedure for their 4 legged stands were to adjust the 4 feet with a stethoscope and tapping technique. Imagine doing this on each shelf as well as the feet ! And if you have a wooden floor that moves, you'll need to retune them each season.
In my 30+ years of audio I have applied the Goldmund mechanical grounding principles on all my components ( and many others ) and in all circumstances converting equipment ( TT's, amps, speakers ), speaker stands etc to 3 feet, single point mechanical grounding has yielded significant improvements in clarity, focus and the removal of resonances and tonal distortions.
In the Goldmund amplifiers, the mains transformers are grounded directly by bolting the transformers to the Goldmund footer, and the transformer is attached to the chassis by lossy connectors. The electronic circuitry is directly coupled to another of the 3 feet for optimum grounding and that foot has a lossy connection to the chassis. The net outcome is that each of these sources of resonance are single point mechanically grounded, and separate from each other, even though they exist in the same chassis. The chassis is decoupled from the others and grounded through the third leg. With non Goldmund amps the "alpha" leg is best placed under the mains transformer which is usually the largest source of resonance.
|
Hi.
The Gyro testing table had 6 cast iron legs. Five of them were height adjustable with wooden decoupling pads. The sixth leg had no adjustment and it directly coupled with the concrete floor. |
Thanks Halcro, you beat me to it. .^) |
Hi Dover,
"A tripod is inherently more stable than 4 legs." I've read variations on your statement many times. But I wonder under which conditions it is true?
Is a tricycle more stable than a (4 wheel) wagon? Think about which one would be easier to tip over if making a sharp turn. But if that is an unfair example for a stationary object, then which one would be easier to tip with a shift in loaded mass while otherwise stationary.
As for camera tri-pods, I believe there are two reasons for their design. First, they are lighter and more portable than quad-pods, all else being equal.
But it is their second design feature that really gives the advantage. The three legs are splayed well outside the center point of the mass they support by angles. And I think it is the angles of the legs which provide the stability, rather than the number three.
Said another way (sorry, I'm trying to find the best way to express my sense of this issue and my question), if we have two small tables of the same weight and height, one has three vertical legs, the other four vertical legs, which will be more stable? If you push on the edge of the top surface, midway between any two legs of both tables, which one is more likely to tip? |
A tripod is inherently more stable than 4 legs. Not true........try sitting on a 3 legged stool? Four legs is generally accepted for stability in chairs.......but in office chairs on castors.......even 4 castors is not sufficient for stability with 5 castors being mandated for safety in the workplace. The reason 3 supports is often used for turntables......is that the 3 supports will ALWAYS make contact on the supporting structure. With 4 supports......depending on the load of the turntable.....only 3 may be making full contact. With 4 legged chairs......a person's weight will 'spread' the bottom of the legs so that all 4 legs are weight-bearing whilst without the load of an occupant......only 3 legs may be fully in contact with the ground? |
Thanks Dover. Sometimes I get ahead of myself when I get hold of an new idea. I tend to get a little giddy and feeling like a little kid. My version 5 will support 3 legs not a problem as they are screwed in on both sides. Project added to the overall list. Its no. 14 right behind no. 13 Build wife new kitchen :^( I am thinking of outsourcing this project so I can play with my audio stuff more this winter. |
09-02-13: Ct0517
Richard thanks for turning me onto the alpha leg :^)
I may try it with the sp10 setup later. One Stainless Steel leg and 3 PVC or other slower material legs. With regard to your proposed 4 legged experiment, it appears that the physics and engineering principles underpinning the optimal mechanical grounding principles have been overlooked. A tripod is inherently more stable than 4 legs. A tripod distributes the weight evenly around the centre of gravity across its 3 legs. This is why cameras and theodolites are usually mounted on tripods, they are more stable. Note also your Verdier TT uses 3 feet to take advantage of this principle. The use of a grounding leg plus 2 non grounding legs to achieve a single point mechanical grounding works far more effectively with a tripod ( 3 legged ) configuration. The Goldmund Reference Technical Report in the Absolute Sound magazine, issue 51 has an informative discussion for those wishing to understand the principles of mechanical grounding. |
Richard thanks for turning me onto the alpha leg :^)
I may try it with the sp10 setup later. One Stainless Steel leg and 3 PVC or other slower material legs. The JN Lenco uses 3 bear paws. I cant even begin to imagine how many development hours Jean Nantais has into this table. It is very much about absorption of resonances and works well. So I am reluctant to try it here. Its 100 pounds doesnt help. If JN is perusing here and sees this maybe he can attempt it. Something tells me he won't looking at a thread with a title that used the word Nude for any ideas :^)
Maybe I will email him.
Cheers |
Dover - Been around since the Mycenae age - the 16th to 12th centuries BC. Had I been around at that time I would have used it in my first TT. I believe that Mr JC Verdier took the concept of the Platine Vintage Granito from this period. He just improved on the remote motor a bit. It used to be a human pedaling back then trying to keep speed stability. Granito is a material composed by little pieces of marble of very different origin agglomerated inside a mold with cement. Machined and polished. The resonance of the plinth with its suspension is about 5Hz and it is well absorbed by the air cavities." Mr. JC Verdier So there are different ways to go about this. You can try to pass resonances through and hope it is one way. Or you can absorb them. The Platine has been scientifically analyzed, studied, and has passed the hardest test of all - time. The way this Platine is made, I feel you could probably place it on any decent kitchen table and get good sound. My Verdier manual provides three options for installation. hard wearing furniture, wall mount, sandbox. My Vintage Granito is on a solid maple platform which utilizes an elongated sandbox, on the concrete floor. Not as pretty and "audiophile" as a vibraplane. But I don't have to worry about maintenance and adjustments due it going out of level and leaky bladders :^). I also don't feel a need to please other audiophiles....just myself. But I am my worst enemy. Glad I am a hobbyist and not in this business. Now with my other hobbies I can see getting into one of them on a business level later. cheers |
The table must have been 20 years old back then. Meaning the concept is at least 50 years old. Ah yes - the tripod. A tripod provides stability against downward forces and horizontal forces and movements about horizontal axes. The positioning of the three feet away from the vertical centre allows the tripod better leverage for resisting lateral forces. Been around since the Mycenae age - the 16th to 12th centuries BC. Had I been around at that time I would have used it in my first TT. |
Yes the concept works. I used it in my first Home built TT, back in the late 70's. The idea was borrowed from an ancient Gyro testing table I saw at Air NZ. It had adjustable feet with wooden pads connecting the floor and one fixed cast iron foot. Cast in one piece into the chassis.
I asked my supervisor why?
His answer "to keep it still"
The table must have been 20 years old back then. Meaning the concept is at least 50 years old.
My comment about not truly working was around the " road block" probably not being absolute. There is likely some leakage thru the softer feet.
Cheers. |
08-26-13: Richardkrebs
From reading here it seems that those that prefer hard supports make them all out of the same material. I believe that this arrangement can be improved, if your goal is to wick energy out of the TT structure. By using, say, three identical hard feet you are creating multiple paths to the shelf (ground). This is the electrical equivalent of an earth loop. This is certainly not new. The seminal article for mechanical grounding in audio equipment as applied to turntables was the Technical Report by Martin Colloms of the Goldmund Reference published in Volume 51 of The Absolute Sound magazine in 1988. Colloms undertook a complete dissection of the design of the Goldmund Reference including the single point grounding methodology that Goldmund employed. I would highly recommend anyone interested in TT design obtain a copy for reference. Some of these mechanical grounding principles were deployed to their entry level products such as the Goldmund Studio that richardkrebs owned. Each time there is a change in materials some energy passes through and some gets reflected back. For example if you have a mat on a platter, then some energy will pass through from the mat to the platter, but some energy will reflect back to the record/stylus and smear the sound. This is basic materials engineering. Providing properly designed pathways to drain unwanted energy from the stylus, record interface through the platter to ground in order to prevent coloration from energy reflecting back into the record and stylus has been around since the 60's, moreso in Japanese audio circles. The Final Audio Parthenon from Japan released in 1971 is essentially a nude turntable with defined energy paths from stylus to ground. The designer Kitamura explains that the amount of energy generated by the interaction of stylus and groove is much higher than required to drive the coils, and therefore unless the balance of energy is drained to ground, it rebounds and resonates the turntable, arm and cartridge, superimposing resonances back into the playback. This is documented in a review of the Final Audio TT in TAS Volume 8 #30 in 1983. The absence of resonance, which results in a clarity and density of tone unparalleled by other TT's I have auditioned such as the Goldmund, Micro Seiki's. SP10's, L07D's etc is one of the primary reasons I purchased the Final Audio Parthenon. 08-29-13: Ct0517
If I understand you are using three leg supports under your triangle TT.
One is the "alpha" leg the leader for energy transmission, while the other two are slower followers? Are you not worried about energy in the plinth getting built up in those two areas with the pvc legs? Did you have a way to test this other than by listening?
08-29-13: Richardkrebs
Like your Alpha leg analogy. Actually, with the other two feet, we are trying to block energy transmission as much as possible although in practice I doubt that this can truly be done. Actually it does work. With electrical grounding the signal always finds the path of least resistance. With a mechanical ground, as discussed, providing a single path to ground results in a cleaner dissipation of energy. Mechanical resonances and disturbances will find the path of least resistance to some degree, but there must be a logical path in terms of materials selection, transmissibility etc from platter to ground to minimise backward reflections. In the richardkrebs example the resonant behaviour of the hard footer will result in a specific resonance absorption and transmission/reflection profile, whereas the soft feet will attract a resonance absorption and transmission/reflection profile that is quite different. If one were able to put together a mathematical model of the structure and materials composition, then minimising the resonant behaviour and backward reflections can be calculated quite easily and would be more reliable than listening since no system exists without colourations due to room or other equipment.. |
Chris.
Like your Alpha leg analogy. Actually, with the other two feet, we are trying to block energy transmission as much as possible although in practice I doubt that this can truly be done. The PVC feet are softer than the plinth and the shelf, acting like a road block.
I have tried this approach on all of my home brew and some commercial TT's, it doesn't seem to matter if there is weight asymmetry.( That said, my current triangular TT is virtually weight symmetrical) In all cases IMO, the one spike and two "feet" arrangement was better than 3 spikes. A trend is that, for a conventional plinth type TT, the spike goes close to where the tonearm is. I don't see any issue with energy build up in a suitably rigid, hard chassis.
The idea is to get mechanical energy out of the system quickly and cleanly.
Also I don't think that there would be any issue with this approach on an air or magnetically levitated platter.
No figures to back all of this up. Just listening.
Cheers.
|
heavy "weight bias" to the front left when viewed from the front maybe its the front right side now that I think about ..... its been too long. |
Hi Richard - thanks for sharing those ideas.
If I understand you are using three leg supports under your triangle TT.
One is the "alpha" leg the leader for energy transmission, while the other two are slower followers? Are you not worried about energy in the plinth getting built up in those two areas with the pvc legs? Did you have a way to test this other than by listening?
My sp10mkII when being set up on my SS legs clearly shows a very heavy "weight bias" to the front left when viewed from the front - where start/stop switch is. Is the Sp10mkIII similar in weight distribution?
Would this mean the alpha leg goes on the heavier corner of your plinth ?
also I am curious.
Do you have an opinion on how your theory would work with a turntable that does not use a thrust bearing?
Air Bearing or Magnetic propulsion for levitation?
thanks |
Hi Lewm - you posted Lewm - From the photo, and the two smaller inset photos which I cannot get my computer to enlarge for me, I think I see that the SP10 sits on spikes that are inverted such that their pointy tips are going up into the threaded bolt inserts on the bottom surface of the SP10 escutcheon. I don't see anything "compliant" in that. Sorry for the confusion. The photo was my feeble attempt at a type of collage showing the latest setup Version 5. But the previous pic also showed the previous version SS legs which confused things. Here is an updated pic. http://cgim.audiogon.com/i/vs/i/f/1377781727.jpgVersion 4 is the bottom right pic. Moving clockwise Version 4.5 can be seen and then the latest Version 5. Version four uses the pointy Solid Stainless Steel legs - the points are matched to the indentation of the cone footers They are heavy enough couple pounds each; add in the sp10 weight - and you easily indent the shelf they are placed on. In this case its a Mennonite made maple block (acting in the plinth role in this setup). The threaded flat holes at the other end of the SS pointy legs use a threaded joiner and that side gets screwed into the sp10 (in all versions) Various different materials can be wrapped around the threaded joiner before inserting and will affect sound. The latest setup shown - bigger pic - has everything rigidly bolted in SP10 and Armpod. The SS legs in this version have threaded holes both ends (with threaded joiners at both ends for bolting into the sp10 and the black shelfl which in this set up, is now in the plinth role. The same maple block is no longer playing the plinth role and has been decoupled. My definition of a plinth (so no confusion with my post)the immediate base structure that holds all the TT system goods. :^) You had posted earlier Just by eyeball, your brass pod appears to be canted with respect to the SP10 platter surface. Probably an optical illusion. isnt this whole hobby a sort of audible illusion ? Its probably the phone camera shot in low light but even if it was a mini version of a leaning tower a pisa it would not matter. The ET2 mounted on it has three leveling spikes and can be leveled on any surface. I have also had the top mounted Dynavector tonearm on this solid brass armpod. Now a tower of pisa would be a problem with it. I'd like to mention a small but very significant point. I add some oil in the one hole at the top of the brass arm pod that is used to secure the ET2. I hear the difference. I believe the oil works (with resonances) in a similar fashion to the actual damping trough on my reference ET 2.5 which is in my main room. Cheers |
Another design philosophy that one might consider is to minimise the number of joins and material changes, hence transmission speeds, between the LP/platter interface, around the loop to the arm and cartridge/stylus. Empirically it would seem to make sense that a join between dissimilar materials could do some damage to the integrity of this loop. This could include CLD techniques which, while very effective, should be implemented with this in mind.
Something for consideration? |
Nice one Richard, makes pefect sense to me. Something I will keep in mind for future projects.
I have always found it difficult to find adjustalbe footers for turntables to my liking. I like the ones that trans-fi makes that I use on my garrard but they are just too large for most tables. He uses o-rings on the bottom of the protector disc so should be easy to try by removing one.
I would think your method would be easily adopted to a table with fixed armboard compared to a table with multiple pods. Suprised the market hasn't adopted this method yet that I know of. |
Halcro.
Part 2.
The same reasoning would suggest that there should be only one path from the LP surface thru the chassis, shelf, to the tonearm and on to the stylus. Your present iteration has more.
Thanks. |
Halcro.
My TT uses one fixed duralium foot with a central tungsten carbide ball which contacts the shelf. This gives a point contact much like a spike. The other two feet are PVC discs 80mm in diameter with a rebate such that the circumference only touches the shelf. These are adjustable. See a pic on my web site www.krebsupgrade.com
The triangular TT where you can see the adjustable feet.
My view on this is that having multiple paths to a mechanical earth creates a smearing effect that is clearly audible. "Earth loop" was perhaps not the correct description. The common electrical paradigm is that a component must have only one path to earth. My view is that the same holds true for mechanical systems.
So, yes, if you use spikes only one should have direct contact with the shelf (earth). The other two should be coupled to the shelf with a slightly softer material than the spike itself. I am not advocating anything that would be considered compliant here, just something softer than the spike, maybe a hard plastic.
Simply another point of view.
Thanks.
|
Richard,
agree with you. i would also go for something between the spikes and the shelf. Harmonix has fantastic small plates to put the spikes on (not that much expensive). Does it change the sound? Yes, definitely!
Or you end up with putting the table on a Harmonix RSB-1 platform. Does it change the sound? Yes! Does it change your budget? Oh yes... |
Richardkrebs,
I'm not sure if I understand you correctly?........
Are you proposing using spikes with only one of them contacting the shelf material directly....whilst the other two have plastic discs placed under them?
And could you please explain what you mean by an "earth loop" in this situation? |
Hi.
Typo in my last post. Please substitute the word "mechanical" for "electrical".
Thanks |
Gentlepeople.
The debate between those that like compliant type supports and those that go for the hard supports has raged on forever. My view is that if you have a suitably still shelf, hard is the way to go. From reading here it seems that those that prefer hard supports make them all out of the same material. I believe that this arrangement can be improved, if your goal is to wick energy out of the TT structure. By using, say, three identical hard feet you are creating multiple paths to the shelf (ground). This is the electrical equivalent of an earth loop. I have experimented with identical and dissimilar feet on my TT and have settled with one fixed using a tungsten carbide ball, and two adjustable using large PVC discs. The PVC discs are softer than the plinth material and in theory tend to slow and impede transmission. The single TG ball is fast and creates one clean path to ground.
Just another view on things. |
Chris, Without getting into the debatable issues, I am trying to figure out how your own description of that SP10 matches with what I think I see in the photo. From the photo, and the two smaller inset photos which I cannot get my computer to enlarge for me, I think I see that the SP10 sits on spikes that are inverted such that their pointy tips are going up into the threaded bolt inserts on the bottom surface of the SP10 escutcheon. I don't see anything "compliant" in that. Then I see also that you are a Copernican; your tonearm is on a heavy brass pod. Is all of the above correct? Just by eyeball, your brass pod appears to be canted with respect to the SP10 platter surface. Probably an optical illusion. |
What we really need......is for Banquo to remove the outer sheet and report what he hears as his leg supports are under the turntable rim like mine now are.......and his has always been like that. |
You may be right Ecir?
But I think the sound changes are more complex than the simple support?
And the fact that the speed read-out hits 33.33 rpm straight off every time instead of hitting 33.32 rpm for 3 seconds before moving up to 33.33 rpm.....indicates an electro-magnetic improvement to me? |
isolated/decoupled or coupled. Chris looks to me you have the best of both worlds on your SP10. As a basis a table that uses pods I would couple, a table with fixed armboards I would decouple. But nothing is fixed in stone since it would be hard to compare any two situations for any examples in this thread, just too many variable independent to each users platforms. i.e. Halcro, it looks to me that your TT is decoupled from its steel structure sitting on those rubber pads which has given you a positve result. I would suspect the changes you are hearing are not so much the metal shield but more from how the deck is now suspended. |
Hi Chris, You will also hear more difference if you put a shelf just big enough to hold the TT and armpods on your existing shelf and decouple it further. Differences can be dangerous? There are many things in this strange hobby of ours which can make our systems sound different? This is really not what I am after
.nor you I think? I am after a closer approximation of fidelity
.a truth to source and a decrease in the many distortions which so easily manifest themselves? 35 years ago
.I read that someone found putting solid rubber balls (cut in half) under each corner of the speaker
decouples the speaker and resulted in better sound. I bought 4 rubber balls the size of tennis balls and cut them in half and placed each half under the corners of my speakers. I must admit I didnt hear a vast difference
.but I listened like this for over a year until I read the theory of rigid speaker de-coupling via spikes? Ralph Karsten of Atmasphere states quite eloquently
.that with an outboard phono-stage, if the sound changes depending on interconnects used
..then one or both sets of interconnects is wrong and is adding (or subtracting) its own colourations. You may be right that placing my whole turntable system upon another shelf which sits on isolators will change the sound? If I then proceed to change those isolators
.most likely the sound will change again? Why is that better?
.and who determines that it is? I bought a complete set of Stillpoint Ultra Minis and placed them under my TT-101 instead of the spikes. The sound changed not one iota! That was a good sign :-) This is a test that you should do Chris
and also Dgob? Anyone wanna buy a set of Stillpoint Ultra Minis? :-) If your system is indeed improved by the added shelf and footers
I suspect that placing a Minus K stand under your turntable will make a bigger difference? One that may be
hard to let go. Something to consider Chris? At some stage
.we all need to be comfortable with the choices and compromises we have made based on experience, learning and intellect. The never-ending quest for fidelity goes on :-) |
Hi Henry - just as you heard a profound difference with the change in TT support and spikes on your masonry wall shelf.
You will also hear more difference if you put a shelf just big enough to hold the TT and armpods on your existing shelf and decouple it further. I used the word decouple not compliant. But I did reference the at-616.
This is what I meant by a dedicated shelf and I was selfishly wondering what it would sound like to you.
Just curious. I thought it would be fun.
I have found many times in this hobby that going against your beliefs can lead to interesting results.
As an example my old VPI JMW 12 tonearm never sounded better than when it was sitting on an armpod which sat on 3 symposium roller block jrs.
With the sp10 setup I showed. I can go from a spiked setup to a bolted in one in a couple of hours.
btw - Have you seen Des' (Dgob) most recent setup?
His sp10 is also on the wall. Guess what lies under it ?
Once you have used the AT-616's its hard to let them go.
probably work great under big amps too.
Continue to have fun and inspire ...
Ecir38 - I just saw your pics. very cool too. nice looking project.
Cheers |
Dear Lew, I forget alas your quote of the comment by Twain about Wagner but I have similar comment about our moderators. They are not as bad as they look. Propably little bit 'prudish' but well sportsmanlike because they allowed my post from 08-23-13 which was not very nice for them. However I fear that my panishment with moderator
approval is meant for life. They obviously have no idea how old I am. |
Chris,
Pneumatic or 'compliant' footers are designed solely to try to prevent the passage of Structure-Borne feedback into the turntable plinth/bearing/platter/tonearm/cartridge system.
Suspended turntables are an attempt to achieve the same result and can be somewhat successful compared to the alternative?
Suspended floor systems....whether timber-framed, steel-framed or reinforced concrete.....are all subject to Structure-Borne feedback which can suffer frequency transmission between 4-10 Hz and depending on amplitude.....can cause physical movement in the flooring system.
The more a compliant footer is compressed....the less successful it is in attenuating these low frequencies yet the less the footer is compressed....the more movement (in all planes) is possible.
That's why a Minus K stand is 'tuned' to specific weights and is able to move alarmingly when pushed?
Because of the problems in effectively designing an integral 'compliant' or 'sprung' footer system for turntables.....most new racks and shelving systems utilise a Stillpoints type of ball and cup isolation as well as constrained layer damping.
This Stillpoints type of footer is used for turntables, speakers and even amplifiers these days.
As you know that my turntable is placed on a masonry wall-mounted shelf and avoids any form of Structure-Borne feedback......I'm puzzled by your suggestion to 'improve' my set-up by using compliant footers?
In my situation....all this will do is introduce possible movement of the footers due to weight shifting of the tonearm and cartridge as well as temperature and humidity variations?
There is no possible 'up-side' to compliant footers if there is no Structure-Borne feedback.
Now if your system is sitting on a suspended floor-mounted rack or shelving system........there may be advantages to your method of support? :-) |
Lewm - Halcro, Good on you that you did not agree with Ct to use compliant footers. We are not so far apart in our thinking. Lewm/Halcro please tell me how my SP10 TT setup is compliant ? The SP10 is bolted into the base at both ends as is the 20 - lb armpod using a recessed bolt. Both the SP10 and the Armpod are easily converted to spikes. Here is a pic for you. http://cgim.audiogon.com/i/vs/i/f/1368395046.jpg Interested in your comments on how to improve it. Its been a neglected TT for too long. I haven't got around to making an aesthetic base for it yet. cheers. |
