halcro, the vta is adjusted using the micrometer ath the top of the post, there is a thumbscrew on the side that you would loosen first, adjust the height and then retighten the screw to lock everything solid. the micrometer has a long rod attached to it that extends to the bottom of the pod. this enables the 1" shaft to be raised and lowered as required.
lewm, i use the 3 thumbscrews at the bottom to adjust for azimuth. it doesn't matter how the armboardor pod ultimately seats, level or not, the azimuth is measured at the stylus using a fozgometer.
don |
Corby, That's quite beautiful work. Do you mean to imply that you adjust azimuth by tilting the whole apparatus via the screw-threaded spikes at the base? Don't you think it's important to have the arm base (=the outboard pod) in a plane parallel to the platter? |
Nice solution Corby.
Can you explain how the VTA adjustment and arm height works via the vertical rod? |
i have been speaking with chris about this thread. he had seen pics of my armpod. you guys are very passonite about this. that's great to see.
my design requirements were to have adjust-ability for azimuth, vta (sra) and flexibility for different arms. the pics show a breuer, but i have already replaced that with a davinci.
i have mounted arms to the armpod that have the wiring come through the pivot point and out the bottom, so a surface mount would not work. i had to use an armboard mounted on a post, on the armpod, to offset the arm. this allows the wiring to exit through the bottom.
pics here:
http://www.canuckaudiomart.com/view_userimages.php?user_id=600
and here :
http://cgim.audiogon.com/cgi-bin/vs.pl?vaslt&1245187375&viewitem&o5
don |
Nandric,
If you buy some aluminium plate (eBay often has various thickness of these at very reasonable prices!) you can make a variety of interchangeable arm plates for the top of your tower(s). The carftsman is therefore only challenged with drilling a hole down the length of the cylinder (55mm in Halcro's and my intended case) and a 30-40mm hole running lower across the cylinder and into the vertical 55mm hole (for the phono cable to run through). That's two holes in total and the weight will be the same as Halcro's.
I already have M6 and M8 taps, drills and footers so no cost there. If not already in possession then, anyone can find these (as I think Chris has suggested) for a very reasonable price from their local hardware store. Three holes tapped for the base spikes; three holes tapped for the attaching armplate. I don't think this is too large a challenge for most on this site. Worth considering I think. |
I have asked some folks who have gone down this path using various metals in an isolated arm pod to post their comments here. I hope they will be able to provide their input.
To me if I had a tonearm with collar - just preliminary thoughts - but anyway to be DIY - You would need to drill collar diameter holes through both the brass cylinder and the top plate and set the spikes high enough to allow the wires to clear. Drilling the holes is easy for a machine shop. The top plate (aluminum?) just needs to be thick enough to allow the tonearm collar to grip and be tightened - then it can be set down on top of the brass cylinder and secured. This could be done by the DIY. Anything more would obviously require a machine shop.
Dear Nandric - I am growing fond of the brass cylinder "as is" and based on what I am hearing am reluctant now to have it taken apart and changed at all.
Cheers
|
To paraphrase the bandit in "The Treasure of the Sierra Madre", you don' need no stinkin' viscoelastic support.
(He said, "Badg-es? We don' need no stinkin' badg-es.")
This is only my opinion, of course.
At least try it both ways, turntable and armpod both mounted on the same inert STABLE shelf with no viscoelastic mounts vs with viscoelastic mounts. |
Dear Dgob, I really hope that anyone will be able to 'go
down the route of Halcro' but I already mentioned Picasso in this context. To accomodate,say, a brass cylinder for
all the purposes (aka 'universal arm pod') the crafstman
need to cut a supstantial part from the cylinder and consequently reduce the weight. Then one will also need the plates ,etc. which add to the unknown costs. One needs some good idea about the cost in advance I should think.
What is possible and what is advisable may contradict each
other. I myself somehow fancy this sturdy brass cylinder and would never polish the thing.
Regards, |
Nandric,
If you go down the route of Halcro (which I am more or less planning to do) with the arm tower design, you can offset your mounting hole to be nearer to any desired edge. This removes all concerns about tonearm length. This will also apply for arms with collars. Remember that I have experimented very successfully with a Morch DP6 and an Audio Craft AC3300 - both of which have collars and are 9" or less in length.
Apart from the unspecified and potential costs in needing professional help in drilling the holes, there really appears to be no limits to the arm tower approach and its applications. |
Dear Lew, Glad to have you on board because you was at first very skeptical about this arm pod undertaking. But
you also provided the info about the obtainable meterials,
brass cylinders included. The further development is obvious:a. the direction of Halcro's 'exclusive' arm pod with 'universal' applications qua tonearm type as well as
lenght b. the direction of the cheap solutions and c.
something in between. My preference is for the brass cylinder with 3 holes + thread on each side but there are
obvious limitations: 9'' tonearms are problematic and tonearms with a collar also. However the price is +/-$200. For the adaptation of the brass cylinder for a more universal use one will need the help of one craftsman with
unknown costs.
Regards, |
Geoch and Nandric, Despite whatever you both may think, my remark about Geoch's phraseology was totally sincere. I really did think it was beautiful prose, but I needed that clarification provided later by Geoch.
I cannot help but note that this discussion is evolving in a direction with which I can agree. Notice that you guys are talking about ever heavier and more stable arm pods that do not move with respect to the tt. This is beginning to be OK with me and to be consonant with my galleon analogy, which Nandric continues to throw back at me. If you take the two boats out of the water (the net effect of putting both the tonearm and the turntable on very sturdy supports and subject to the same forces), then there is no problem. There is even some coupling going on, whether you like it or not. |
Dear Geoch - and others - everything we do in this hobby is at our own risk. We have all lost precious needles.
Only when this happens do people do one of three things. Get out of vinyl altogether, buy cheaper cartridges or be VERY careful.
I will source some Jrs. and try them. This will give me some time to get used to the sound of the new arm pod. I finally added a system page and posted a couple of pictures for those reading this thread.
For those of you thinking we are doing something complicated here - I walked through my house at 1 pm est today with the piece of raw brass and no holes for bolts or threads in it. It is about 5pm now and I have listened to 2 lps already. I let the system warm up while I put it together.
But this is my 3rd version really so give yourself one day to setup.
I can say with the ET tuned to about 75% right now it is sounding very very good.
Cheers Chris
|
Dear Chris, the only thing of great concern is how softy you can handle the arm lift. The JR responds quite sharp to an aggressive shock and your fingers must feel only an affectionate touch as like they slip over when queing or lift down the tonearm. If you try them & regret your purchase, I'll be gratefull to exchange them with my Aktyna ARIS every time. A fellow with a Clearaudio arm has the guts to do it first and the other two just have followed. The total weight of the cart/arm is only a small percentage of the 7kgr tower and cannot affect the balance. The height is irrelevant also as one of them uses a tower of over 20cm height for his Gabriel. If you can manage to soften your ET's lift by oiling & handle it with control then I can't see any problem. I guess there are not many TT chassis permitting an independent arm pod & above that most of the people afraid to use the JR's even under their integrated TT's plinth. So, it is normal for most to avoid such an extreme & dangerous option especially when they are used to the convenience of the pivoted tonearms. I don't think there is any guide about the appropriate mass loading of JRs and I have seen them under everything from light weight Tuners to even massive speakers. I realize the difficulty for everyone to accustomed to the swing threat upon every touching of his tonearm, which may cost his precious cartridge. Although one of these fellows trusted his Insider to JRs, I'm sorry but I honestly can't assure you about your stylus safety by first hand. I don't even have an isolated arm pod ... (yet). |
Dgob - I have no problem being the guinea pig. Will try to source some locally first. I have found in the past when talking with some of these manufacturers of these products that their experiences with what we are doing is limited.
They can't seem to say yes or no to me and their feedback is very general and ambiquous.
Geoch and his audio community are obviously there already. His comments are based on the Jrs. actual experiences with people so I trust his input as been unbiased. And besides as you say they are not alot of money - again about the price of a tank of gas :)
Geoch - I do have two questions
Are there any guidelines about the weight. Have your members found there is a minimum and maximum weight with the Jrs. and is there a limitation on the height of the object.
Also you mentioned that these are used by the parallel trackers but why not the Pivot arm or any other - since they are balanced as well.
Thinking of the pivot arm I am getting visions of a construction crane on a tower swinging over a job site. |
One 16 lb (7.27kgs) Solid Brass Cylinder - 4" x 4"
$152.55 dollars
Brass bolt to secure tonearm to cylinder .15 cents
Steel spikes / discs to couple the arm pod $20 dollars
Drill bit and tap for making threaded holes for 3 spikes and one bolt. $15
Brass Polish $5 dollars
Unbiased, unsolicited, comments and recommendations from Audigon members - PRICELESS
You can see the raw brass piece here.
http://www.canuckaudiomart.com/view_userimages.php?user_id=5181&image_id=41998
I will try it out this weekend and if it sounds promising I will bring it to a machine shop to round it out and take out the fine scratches
Cheers Chris |
Chris,
Sorry, just one other brief thought.
If you look at the details and approach of the Equarack people, you'll see there is a major concern about mass loading/weight of component to get the best out of viscoelastic supports. As I mentioned above, I had major problems when trying noted components on one of my Symposium platforms and so you might want to look into this weight compliance factor in making your decision. Athough, at only $90 you might just think it as well to just get them and experiment!?
Either way, I look forward to hearing how it performs in your rig. |
Chris,
I failed to notice that the original suggestion was to try the rollerblock "juniors". These should indeed be far more stable under mechanical interactions than the normal rollerblocks (which I use). Nandric is correct that you'll have to suck it and see and I thjink you are right to give them a go. Maybe you could even talk to the people at Symposium first. Anyway, there is a set of juniors for sale on eBay now ($90).
Good luck with your experimentation and do let us know how it goes. |
Dear Lewn - you can have the most precise and accurate platter/motor assembly - but once you put that crude piece of vinyl on top with all its imperfections - all bets are off.
I have found through this approach that all you want the platter/motor to do is maintain correct speed and drain its own resonances.
Once the isolated (armpod, tonearm, cartridge, stylus) picks up that signal from the vinyl - its on its own merry way and says bye bye to the platter in a continuing cycle.
If your tonearm is mounted on the same platform as your platter/motor, you need to ensure your system is able to deal with the returning vibrations/resonances from the tonearm. Hence we have some very elaborate systems as a ways of doing this.
This is too complicated and cumbersome and $$$ for me and the reason I like the simple isolated armpod approach. Once my armpod gets rid of resonances, the last thing I want is the resonances returning to play havoc.
Sorry for not presenting this in a more scientific way for some of the members here but this is what I understand to be happening.
We break that resonance loop with the isolated armpod.
The members here using this approach have heard the difference between the two. |
I needed to think about this over night.
I took the soft activity to be any and all the movement that occurs outside of the normal cartridge/stylus retrieval of the signal that needs to occur for us to hear the sound. The tonearm (any type) moves up and down and side to side in normal use. The actual physical movement of the tonearm is itself a soft activity and necessary. Likewise at the other end (arm pod) movement is happening in the armpod with the resonances we just cant see it in the material as the vibrations are either absorbed or passed on. With the symposium jr. you are able to see it more clearly.
The footers of an armpod are like the foundation of the house. They however need to be such that they support the structure but also provide for passing of resonances into the platform below not to return up again or absorption of some of those resonances thereby dissipated. This can be done at least in two different ways from what I have learned.
Hard spikes/disks that allow the resonances to pass through and not go back up. Or they can be of a design soft and hard to absorb some or all of the energy / heat of the resonances and also allow for the remainder of the resonances to pass through. It sounds like the Jrs use this principle.
I have to admit the first time Geoch described this I had visions of a tower shaking during an earthquake. But then if you think about it as it moves as long as returns to position in time before the stylus is on the groove it should be fine. We accept the toearm movement as part of the normal movement why any different at the other end ?
A personal experience (not audio related) but that relates I believe to this bear with me. I have a contractor doing renovations to an old property that uses a large copper drain pipe. Whenever hot water is used it would go down the pipe putting energy into it from the heated water expanding it (causing noise) then when the water was stopped, the pipe would again (make noise) as it went back to its cold form form. We were able to cure this by cutting a couple of inches from a section of the pipe and replacing it with a rubber clamp. Now when the hot water is run the energy does the same thing and goes down the drain pipe but the energy makes its way to the rubber clamp (like the Symposium Jrs.) where the energy is absorbed. Drastically reduced noise. For our hobby this energy in the pipe is like those vibrations and the Jrs. are absorbing and passing it onward.
Thoughts ? |
Dear Lew, you are very difficult to satisfy or please. Even
the 'soft activity' is refused on theoretical grounds alone despite this saying about the pudding. Only the argument is changed from 'galleons' to a movement in concert with the platter. As I suggested (03-20-11) in relation to an brass cylinder you will be able to afford
the most exotic 'spikes' imaginable and those Rollerblocks
JR look to me very appealing. You can eventualy also use them to 'soft absorber' those tube amps of yours.
Regards, |
Dear Lewm, sorry about my English it is obvious that I'm using the dictionary mercilessly. This is what I meant :
The forces created by the cartridge and the tonearm during play, cannot cause any motion to the armpod, as they are received & collected like resonances & not like forces that can cause a displacement.
When we push accidentally an armpod that uses spikes as footers, the disposition even if it is slight, it is also permanent. When the footers in use are these Rollerblocks JR, the displacement of the armpod is quickly self-corrected and the whole moving mass is coming back again to it's exact position by smooth & progressively reduced circular move.
This activity is taking place from the moment that we release the arm lift and continues decreasingly so, as the arm tube is falling to LP. But it comes to an end before the cartridge reach the vinyl surface. Any further remaining activity that left, are only the resonances that caused by the usual suspects during the listening session & not by the Rollerblock JR which is way more gifted than spikes in draining these resonances. |
..."in normal careful use, the great mass of the armpod impedes any disposition and restrains it to a soft activity." Geoch, that is beautiful English, worthy of an erudite 19th century scientific journal entry. But what is "soft activity"? Any activity, if activity means movement or motion, is a bad thing if the platter does not move precisely in concert. |
The "JR" has some advantages over the more expensive std Rollerblocks :
They have 1.86" disc plates on both! levels that are both! threaded at the outer side and are also both! curved inward. So, we can permanently fix them in the desired place at the upper level (armpod) and at the lower level (shelf). The disc plates are shelf centered with great precision by gravity as long as the shelf is allready dead leveled on horizontal plane. The 1.86" threaded disc plates can provide further leveling adjustment and their contribution is admirable in contrast to spikes/thin discs. The movements by accident are terrifying indeed, but in normal careful use, the great mass of the armpod impedes any disposition and restrains it to a soft activity. The remaining faint movement is progressively die out very quickly before the cartridge touch the LP. Of course it is a matter of the end user to value the pros & cons of this option, but the disadvantage of the careful operation & handling is an accustomed practice anyway to the parallel tracker's user. If you have a friend by which can borrow a set of 3 Rollerblock JR and see if you can manage to handle their lateral movement, it is definitely worth a try. |
Dear Geoch I am trying to understand the benefit or reason for using the Rollerblock Jr.
Based on what Dgob is saying and the fact the Rollerblock use bearings how much weight are we really talking about when you say really heavy loaded.
I ask because I have two 2 ET tonearms. If there is one thing I have learned about that air bearing - is that it is very sensitive. It is set at 19 psi and it needs to be totally rigid and parallel once set and not move or it will introduce coloration, and distortion that is audible.
But I also think that this would apply to other "pivot" arms as well - any movement at all is not good ? |
Here in Greece it is common place the Rollerblock JR under really heavy mass loaded free standing arm pillars when we are using parrallel tracking arms. |
Geoch/Chris,
I'd be careful about using Rollerblocks beneath an arm tower. The ball bearings are not secure enough and movement when lifting and placing the arm would almost certainly create ongoing alignment problems. In fact, the only place that I find the rollerblocks ideal is beneath my CDP, where mechanical movement is minute enough to never create a problem and yet the benefits can be easily heard. |
Dear Chris, I present to you my reservations about the possibility of ringing. The 7mm Brass is a lengthy piece and the porpotions are not quite ideal for doing this "air" mounting. Furthermore I believe that the 3 tiny bolts are not so absolute idea in terms of controlling the resonances, even if they can provide the convenience of alignment, the threaded holes together with the asymetrical body of the tiny bolts , are not comparable with some pretty harder & perfectly round bearing balls in order to detune the armboard resonance & above that, in terms of rigidity are more secure.
I'm with Halcro at this. You better try the massive & solid approach -as the more secure way- that is also more tolerant to some crafting inaccuracies. Also keeping the project simple is always the better way. I agree with your choise of Al plate / Brass pod / Steel spikes for your next project. (Although I prefer the Symposium Rollerblock JR instead of spikes) |
Dear Chris,
The stainless steel pricing looks better than the brass. The only down side is it is harder to mill yourself so you might need a professional machine shop?
I'd go for 316 grade rather 304 as it does not tarnish and is definitely non-magnetic.
I can't quite follow the 'air' reference to the top-plate? I personally would want the top-plate connected to the mass of the armpod as securely as possible. In fact the only reason for a top-plate IMO is to allow clamping of the tonearm and connection of the Din cable, otherwise I'd happily screw or clamp the tonearm directly to the armpod.
Cheers
Henry |
Dear Geoch and Henry thank you for providing very valid points for consideration. My current armpod has served its purpose - it was built to determine if this approach was valid. It was not expensive to make as materials are available and cheap where I live. I am ready to setup up the next one.
It can be done in stages and allow me to use at each stage. I enjoy the DIY approach so would like to continue this way - Thinking of a 4 diameter brass cylinder pod and to mount my Tonearm directly to the top of it with three steel spike couplers on the bottom. This would be the first stage.
I then would make a decision on whether to add a top plate of aluminum to the brass. I need to think more about what has been said here about this.
I was speaking to Bruce of Eminent Technology who informed me that my tonearm uses Cone Point Set screws to level itself to the base. These come in many lengths and diameters.
http://www.radax.com/store.asp?pid=15198
I could mount the top aluminum plate on the brass using the same approach. 3 of these screws close to the perimeter to level it. 2 or 3 bolts would then be placed just outside of the footprint of the tonearm base that it will sit on it to secure it to the plate. The plate would ride on air as well as the tonearm. Do you feel this air is an advantage or does it not matter ? Can I get your thoughts on this.
From a DIY point of view - It seems to make more sense if adding this plate to just have it touching the brass at specific touch points with the set screws and bolts and making sure no movement and it is rigid.
I did some research today on materials and pricing.
Metal Supermarkets is located in Canada, the US and the UK.
http://www.metalsupermarkets.com/MetalGuide.aspx?CategoryID=BRASS&ProductID=TUBE_ROUND&ProductSubCategory=360
Prices are for solid brass and SS armpod cylinders. Prices are in Canadian dollars.
4" diameter brass (360 grade) 4 inches high - $152.55 (16 lbs)
3 diameter brass (360 grade) 4 inches high - $79.91 (9 lbs)
4 diameter Stainless Steel 4 inches high - $94.81 (15 lbs)
3 diameter Stainless Steel 4 inches high - $59.71 (8.5 lbs)
3 or 4 (7 mm - approximately ¼ inch) brass top plate is about $10. |
Dear Nandric,
the "trumpet" attached to Thuchan's TAD-2002 driver was designed by me and I prepared the technical drawings to have it fine milled from one solid piece in a 3D-CNC-precision milling facility here in Bavaria.
It was not easy.
It is however kind of Thuchan's property now.
Furthermore it only works with the bandpass of his X-over, the TAD-2002 and within and in conjunction with the whole Bavarian Voice-system.
Nothing that can really be copy-paced and transferred to another speaker.
Cheers,
D.
post scriptum: Halcro is right - it shouldn't be all that problem to find tooling-facilities around any major city in europe or the US who can handle milling work on solid metal (or wooden ) pieces to create nice armpods. |
Dear Halcro, Thanks for the lecture reg. 'structure-and air born(sound) transmission'. This is done in the context of the arm pod formulation but, cause of the generality, must also apply to the TT's. We can see, so to speak, two
opposite approches: Raven, Brinkamann, Kuzma XL ,etc. on
one side and ,say, Thorens and Linn-LP12 on the other.
But the last mentioned use springs while the other don't.
Does and how 'mass matter' in this context? BTW this is a
kind of reformulation of my earlier question.
Regards, |
Dear Halcro, I can't see even one point in our texts that indicates any dispute. The armpod is by nature isolated once it is free standing & not attached to the TT chassis. Other than this isolation, not me, neither you we were willing to recommend any farther (ie: under the spikes' discs, or even in between the metal layers) as long as we can verify the ability of the shelf to drain the vibrations that intruding from air & floor, and also the effectiveness of the 6x1cm steel discs to drain the resonances coming from up through the spikes. But I feel that we must perceive the spikes as couplers. Theoriticaly we use to refering as decouplers all those viscoelastic materials that we want to avoid. I think as its going till now, this project is promising. Have you noticed any contradiction in the process so far ? |
I'm sceptical about all this 'isolation' of the armpod that is being discussed?
Sound is transferred in only two ways:-
Structure-borne transmission
Air-borne transmission
In both these cases, we are interested in transmission in two directions......from armpod to tonearm and from tonearm to armpod.
With the tonearm mounting to the arm pod in the first instance, if there is any 'transmission' from the tonearm base, this indicates 'movement' in the tonearm base which is 'information lost' from the cartridge.
The aim of the tonearm is to have zero friction at the pivot point which means no transfer of any movement to the arm base. The arm itself must
be rigid enough to allow the cartridge to transfer all the stylus movement
to the tonearm wiring only.
In the other direction, the base upon which the armpod sits needs to be stable and immovable. The armpod needs to be 'decoupled' from this base (unless the base itself is acoustically decoupled and levelled) via spikes and the armpod must be absolutely level. With the mass of the armpod (at least in my situation) so large, any structure-borne transmission which somehow transmits across the spikes, is so small and high in frequency, that it is easily absorbed as 'heat' by the armpod.
With the air-borne transmission, please remember that the tonearm and the cartridge assembly themselves, are both directly affected by these same sound waves and are far more susceptible to vibrations (because of their more delicate masses) than the tonearm bases and armpods.
Again if one employs mass-loaded armpods, the amount of sound at varying frequencies which can be reflected and/or absorbed as heat is far more than that of any tonearm or cartridge.
If one wishes to employ a combination of dissimilar materials to counter the transmission of certain frequencies, I see no harm in that as long as visco-elastic ones which allow movement to occur, are avoided?
The above is simply my opinions based on the physics, acoustics and materials science with which I am familiar as well the 'in-field' experience of my Project. As usual YMMV? :-) |
The SME type base of my Pluto 9A tonearm is covered with a very fine velvet textile, but has greater mass & height for it's small dimentions, is made of titanium that is bonded to a brass lower level & furthermore has 4 bolts that compressing the thin textile underneath and eliminate the possibility of compliance. To use only 2 big bolts its risky for this option as is also dangerous for the 3 bearing balls solution. There, you change the resonance freq by tightening the 2 big bolts, but they leave a free & lengthy surface that remains open & undamped to the mercy of any remaining vibration. |
Dear Geoch excellent post. You have provided me with three clear options that I understand and am thinking about.
you can cover the entire underside surface (except the 2 holes) with a very fine velvet textile (extra thin without compliance) in order to damp the 2 metals that are coming in contact.
This would be an easy solution and I can experiment with different velvet textiles.
2 bolts may not be enough for the 3 coupling spikes option and can provide space for ringing or even worst a possible diformation of the Brass platform.
Excellent observation.
I could add 2 more bolts to form a square around the 3 spikes? I can make the Brass plate smaller as well ? The ET tonearm post covers a very small area on the armboard.
replacement of the upper coupling spikes under the Brass armboard by very tiny bearing balls (if you decide to try this option, by this way becomes easier. I'm anxious about the proper amount of tightness by the big bolts
I really like this option - picking up some ball bearings is easy but just like torquing special wheels on cars - how do you know how much torque to use on the bearing. I guess I would start with a low torque and listen to familiar recordings tightening a little at a time. When I used my TNT belt drive I would adjust the SDS by tone so I trust my ears for this.
You have to choose by trial & error these 3 options unfortunately we cannot predict the results
Everything we are doing in this thread is uncharted watersfor me that is the allure of it the discovery the learning first hand how resonances work in my vinyl setup. We only need to please ourselves. This makes the improvements very satisfying.
I have learned alot by your post.
thank u Chris |
Dear Chris, IF... (and this is very important)... you keep the 2 big bolts also, to maintain the contact firm, then...
the spike couplers under the 7mm Brass armboard are using the same logic of Orsonic headshells & Midas Touch indermediate headshell weight : They provide a clean (rigid coupling without soft materials that have any compliance) but short path and thus allowing only a fraction of the resonances to pass through the next level.
This is not counting as an isolation (rigid coupling of metals) and it seems that it works for cartridges !!!
Now I'm thinking an alternative : As the 2 bolts are allready provide a path from Brass armboard to Aluminium armpod, you can cover the entire underside surface (except the 2 holes) with a very fine velvet textile (extra thin without compliance) in order to damp the 2 metals that are coming in contact. This is a very different option from just applying the silicone oil to the same surface. You have to choose by trial & error these 3 options unfortunatelly we cannot predict the results. Depending by the mass of the armboard, (and especially the tolerances in execution) the 2 bolts may not be enough for the 3 coupling spikes option and can provide space for ringing or even worst a possible diformation of the Brass platform. I would prefer : ability adjustment only at the bottom spikes, the steel discs about 6cm diameter and replacement of the upper coupling spikes under the Brass armboard by very tiny bearing balls (if you decide to try this option, by this way becomes easier. Although the marking points of the Brass armboard & the Al armpod by the bearing balls is of no concern 'cause they can only form a round scuff, I'm anxious about the proper amount of tightness by the big bolts).
Of course anything soft under the discs makes the whole armpod isolated from the shelf, interrupting the passing of resonances from armpod to the ground and it needs experimental verification also, since it is only depended by the shelf prorerties. |
Hi Chris, Is Panzerholz effcted by humidity or dry conditions? Im assuming it would. Directions point out helpful guide lines , one being after cutting seal cut edges.
This being a product designed for multipal applications in heavy industry it being in your home used for delicate duties I so far found no issues over a year in use.
It is extremally dense stuff dulling high grade carbide cutting edges very quickly.
For use as arm pod or plinth material for sure. Is it like other material commonly used in audio, No.
Is a plinthless table a good sonic step forward, Yes
Is a table set into a panzerholz plinth a sonic step forward , Yes
Cheers |
|
Dear Halcro, I know that you are a very 'smart cookie' but
clairvoyant? Well as you presupposed I was able to find a
craftsman with an CNC lathe in Holland and I really enjoy
to look how he works with this 'monster'. However Thuchan
is a different 'cookie'. He is an entrepeneur with a clear
thought of what he wants and has the capability to organize all the needed work. Dertonarm is btw a close friend and they are at the moment adjusting the Bavarian voice (aka speakers). So obviously he was also in the position to find all the needed professionals in Germany for the job. So you made a good quess. I am in particular interested in this 'trumpet' in front of the TAD 2002 driver but even Daniel was not able to explain to me what
the 'clue' is . My shortcoming of course.
Regards, |
Dear Inshore - look forward to seeing a picture of the armpod. Just curious as you mention humidity - Is panzerholz affected by humidity as other woods - maple, oak and birch?
Cheers Chris |
Dear Geoch - thank u for your recommendations. I use the discs under the spikes. I have however been experimenting with different materials under them. The most recent pics in the site link show the discs along with the removal of the armboard top plate.
Will consider the 7 mm brass top plate but have a question.
I like the design of the ET post mount which has one bolt holding it with 3 leveling threaded spikes surrounding it. It can be seen in the link here.
http://www.canuckaudiomart.com/view_userimages.php?user_id=5181&image_id=41907
How do you or others here that have looked into isolation between metallic materials feel, on whether the top brass plate you recommend is attached firmly against the armboard below (easy to do) or if it should ride on air like the ET post mount. More difficult but still easily doable. I would just need to find a place that sells the threaded spike couplers to use with it.
Then the top two levels of the armboard would be riding on air.
Henry - it appears your arm pod top plates are screwed directly to the armpod ? Did you consider this ? What if that top plate was riding on air like the pic in my link ? Would it increase resonances or provide more isolation?
Any thoughts on this ?
Cheers Chris |
Dear Nandric,
Thank you, that's very flattering but I can only 'design' the armpod.....I can't make it.
For that I need a good foundry to make the mould and cast the bronze after which I need a good machine shop to make the aluminium top plates and to drill and tap all the holes so that a good automotive paint shop can finish the job with 2 pack polyurethane.
Here in Australia we are lucky that there are many places which will readily do small quantities or 'one-off' jobs like this.
I'm sure in Holland you could also find places?.......look how Thuchan was able to have his new speakers made so professionally?
Of course.......price may be a factor and that's why Chris and Lew are looking at commercially available billets of brass and stainless steel which may be available in the States.
Solid billets of the sizes I designed are simply not readily available in Australia.
There are many people who can 'draw' like Picasso...........there are very few who have the IDEA of what to draw?
That's the difference between a 'craftsman' and an 'artist' :-)
Regards my friend |
Dear Chris, It will change for sure, but you need an intermediate level of different material in order to break up the resonances. If I was in your position, I would start with a 7mm Brass top plate for armboard, and Steel for the discs under the spikes. By this way you have the Goldmund's list & sequence of metals. I'm not supporting their option, but you may want to try something that is so much praised by them.
Kind Regards |
Dear Halcro, I am truly glad to hear this;we are cool now.
But your arm pod remind me somehow about Picasso. 'Look',
he said to a friend, 'how easy drawing is'. He then draw with a single stroke a pigeon. 'Anyone should be able to do this'. He added. Now an arm pod is of course a'different
animal' but do you really think that we can make the same as yours? If so I don't believe that I am able to understand anything about Australians. Except of course that they must be onbelievable optimistic kind of the human kind.
Regards,
Regards, |
Dear Geoch - thank you so much for your thoughts. You are absolutely correct - I can eliminate that wood layer totally and mount the ET directly to the armpod with the one bolt. The mounting post rides on air with 3 of its own couplers. The plate I am using is dried oak and it is firmly held on with 2 - 1" inch machine screws. I used the plate to allow for ease of changing arms but I will be making other pods for those arms so it is not required. Now the important part - how much will it change the sound by removing it.
I will think more about the second part. The adjustable AT616 footers are at their lowest point right now and they adjust much higher to accommodate a higher pod. My problem is at the pod side I will need a taller one.
So for the interim I think I will replace the AT616s with the lower mapleshade spikes I was using previously this will give me the room to experiment with the pod and that layer.
Henry My VPI 12 arm mounts directly on top with phono cables out the side. It is very easy to drill a hole into the armpod to accommodate the bottom cables especially if aluminum. But it still wont look as good as yours. Our imagination is the only limit here. Many ways to skin. |
Dear Nandric,
I'm certainly not angry with you :-)
A little disappointed that you didn't understand my sense of humour about your 'Australia' remark which I found very funny :-)........so I thought you took offence?
I hope we're 'cool'?
Regards
Henry |
High Density & CLARITY are BFF |
Hi Chris, I think the decoupling offered by the wood plate is a very drastic solution, applied in desperate situations. My concern is about the strength & tightness of the surface that couples the arm pillar with the arm pod.
I'm sure it works OK, but from the theoritical point of view, I would be more comfortable if you choose a more solid upper fixed point, in order to modify the ET arm pillar, as if it is one piece with the first block of the arm pod. Even if it is applied at the bottom* (the decoupling by wood), may not be necessary -in your case- considering there is a film of air in between the arm tube & the arm pillar.
* Steel at the top plate, your own Al main block, Brass as a foundation or intermediate level. Especially the discs that rests the spikes must have great hardness. You can close the microscopic open moleculars between the metal surfaces simply by applying some silicone oil without bonding or bolts. Easy if you uplevel your main wood shelf with a second & preferably denser platform only for the TT and so, you will have the apparent hight for steel, brass & discs. Just a thought. |
As I understood the manual, any armboard will do. Part of it will be drilled onto the pod and the part with the larger hole where the tonearm mounts into would protrude beyond the dimensions of the pod itself. So, this would be different than Ct0517's set up but would still work for pivoted arms. In fact, that's what I did the first go around, but instead of using a metal foundation, I used red oak.
My current pods are similar to Halcro's; but, sadly, far less cool looking. |
Dear Geoch, 'life is to short' but it is never to late to learn. So as soon as I get my engeneering degree I will
respond to the 'demping question'. Meanwhile you can direct
your inquisitive mind to Vidmantas and ask any question about cork you like (Ruta@reed.lt or Vidmantas@reed.lt).
I am very reluctant to ask Halcro to bring some 'light'
in this 'mass matter' because I think that he is angry at
me.
Regards, |
