View Full Version : Armboards...a neglected subject?
They really matter with many arms. It affects performance to a surprising degree, especially if the arm is a 'stiff' one which transmits lots of energy. I first realised this 20 years ago when dear old Arthur Khoubassarian produced a special board for the newish SME Five. The board was deeply sided and made from a sandwich of materials. It transformed the bass heaviness of the Five on Pink decks and sounded just great. Modern heavy SME arms seem to like brass armboards (which SME use sometimes) but don't work so well on acrylic or aluminium. Worth experimenting. Put the Five on a poorly mayched armboard and you waste the quality of the arm.
No doubt other arms are in the same position of needing a suitable termination. Some sort of 'lossy' sandwich is often a good bet. But I suspect each arm is a little different....each may need different termination.
I've experimented quite a bit with armboard design and materials - including carbon fibre, laminates, aluminium and constrained layer damping; I would agree that armboard design is often overlooked by both users and designers but does make a significant difference and impact upon arm performance. The armboard I use now is an aluminium constrained layer construction.
Yes, constrained layer damping, a 'sandwich' is probably best for many arms. I think that, rather than buy a new arm, people might get a useful improvement by changing the armboard. Something like marine ply is a type of 'sandwich' and might work well for little money. I wonder about the Rega arms, which being a single casting can transmit a lot of energy. They might benefit. When you think of all the time and money spent on things like recabling, I can't help suspecting that the armboard might give a greater return for the effort. Oddly, for this hobby, I don't know of any firms offering replacement upgraded armboards. Aerolam was used by Pink, as sort of aluminium 'bubbly ' construction. I seem to remember they also used a sandwich with balsa wood.
I have no experience of the Linn mountings, but I wonder whether some of the replacement chassis designs, and indeed the 'keel', partially work by offering a better termination for the arm.
freefallrob
25-02-2015, 11:41
I'd imagine that the amount of energy put into the arm by the cartridge has a large effect, some MC's put a lot in to the arm, where as some wobbly high compliance MM put very little in.
Wakefield Turntables
25-02-2015, 11:43
I agree with you and think that armboard design is overlooked. I've used a solid copper armboard on my V to great effect but switching to ebony took it to another level. I've never tried multiple layer designs so that could be something for the future.
The Barbarian
25-02-2015, 11:48
I have an Acrylic spacer, Brass spacer & the original 'P1' SME arm spacer. I prefer the 'P1' as for an arm board i don't have one.
I have no experience of the Linn mountings, but I wonder whether some of the replacement chassis designs, and indeed the 'keel', partially work by offering a better termination for the arm.
That is certainly one of the key aspects of the one I designed (the RubiKon).
Aerolam is a sandwich of aluminium skins around an aluminium honeycomb centre. You can also get a carbon fibre version where the CF skins wrap a honeycomb of aramid fibres (Nomex) and that is one of the CF materials I have used. You can also buy end grain balsa sheets with CF skins bonded to it.
excellent thread and perfect timing,im just about to fit a rega rb300 to my AR turntable,what would you guys recommend i try?
Yup, experience also tells me that arm boards (in terms of what they’re made from and how they’ve been constructed) have a significant sonic influence on the performance of a turntable. Good T/Ts should have arm boards fitted whose ‘sonic signature’ has been factored into the overall equation by the manufacturer, along with that of the other constituent parts of the turntable.
Think about it: if different styles of plinth have a huge impact on the sound of a T/T, then why shouldn’t the arm board that supports one of the key components of the turntable, namely the tonearm (and the cartridge attached to it), do a similar thing? The fact is, different arm board materials have different resonance/damping properties, and so that means they will naturally influence how the attached tonearm ‘behaves’ - and the effect gained will translate itself to the cartridge.
It’s therefore no wonder that upgrading/improving a poorly thought out and/or constructed arm board can result in significant sonic improvements!
In that respect, I would thoroughly recommend the superb (various) types of ‘exotic’ hardwood arm boards produced by Speedy Steve, of Magna Audio, as they can transform the performance of a T/T, especially Japanese direct-drives (such as the Technics SL-1200/1210) that often don’t respond well to being fitted with any form of metal arm board, which can make for a thin and sterile sound.
I couldn’t believe the difference removing an aluminium arm board, and replacing it with a solid ebony one (produced by Steve), made to the performance of my T/T... Therefore, underestimate the importance, sonically, of the humble arm board at your peril! :exactly:
Marco.
I agree with you and think that armboard design is overlooked. I've used a solid copper armboard on my V to great effect but switching to ebony took it to another level. I've never tried multiple layer designs so that could be something for the future.
x37! Good post Acrylic, Ebony, this is where it is at, dunno why manufacturers keep on with metals.... just my 2p worth.
RobbieGong
25-02-2015, 20:03
Yup, experience also tells me that arm boards (in terms of what they’re made from and how they’ve been constructed) have a significant sonic influence on the performance of a turntable. Good T/Ts should have arm boards fitted whose ‘sonic signature’ has been factored into the overall equation by the manufacturer, along with that of the other constituent parts of the turntable.
Think about it: if different styles of plinth have a huge impact on the sound of a T/T, then why shouldn’t the arm board that supports one of the key components of the turntable, namely the tonearm (and the cartridge attached to it), do a similar thing? The fact is, different arm board materials have different resonance/damping properties, and so that means they will naturally influence how the attached tonearm ‘behaves’ - and the effect gained will translate itself to the cartridge.
It’s therefore no wonder that upgrading/improving a poorly thought out and/or constructed arm board can result in significant sonic improvements!
In that respect, I would thoroughly recommend the superb (various) types of ‘exotic’ hardwood arm boards produced by Speedy Steve, of Magna Audio, as they can transform the performance of a T/T, especially Japanese direct-drives (such as the Technics SL-1200/1210) that often don’t respond well to being fitted with any form of metal arm board, which can make for a thin and sterile sound.
I couldn’t believe the difference removing an aluminium arm board, and replacing it with a solid ebony one (produced by Steve), made to the performance of my T/T... Therefore, underestimate the importance, sonically, of the humble arm board at your peril! :exactly:
Marco.
+ 100 :)
x37! Good post Acrylic, Ebony, this is where it is at, dunno why manufacturers keep on with metals.... just my 2p worth.
It depends on the turntable, Andy, and what effect you’re trying to create. On some T/Ts, metal arm-boards work a treat :)
Marco.
I haven't experimented with armboards as I have simply used what came with the Thorens 124 turntables (as the designer intended). In most cases these are made of a hardwood. I say "a" hardwood since they are painted black, except where the arm fitting has been cut, where one can see they are solid wood rather than plywood or any composite sandwich.
One of the armboards for my SME 3012 is made from acrylic, however I do not use it preferring a wooden armboard. From what I have read, the use of acrylic as a material for armboards is not generally recommended. At one time I thought about having a aluminium armboard machined for me, but decided that maybe it might not have the desired properties. Some arm manufacturers have recommended acrylic (SME) or metal (Keith Monks), but this goes back to the days before people thought about these things, or even plinth construction.
Not being a mechanical engineer, I am not quite sure what is required from an armboard. If the idea is to dump unwanted vibrational energy from the arm into the mass of the deck, then the connection to the deck needs to be made rigid. This suggests a stiff material like acrylic or metal. But if the connection is an acoustic mismatch energy will be reflected back to the arm, so maybe wood is better having some form of self damping. Linn use (or used to use) a thin plywood layer sandwiched between two layers of hardboard. Perhaps I ought to have an experimental armboard having such a construction made for my Thorens 124s. :scratch:
My fourth deck is an EMT 930 where there is no armboard as such: the arm collar is fitted directly into the deck. Despite appearances, the deck is made of Bakelite, chosen by EMT for its acoustic properties. There is little room for experimentation here.
I'm not a fan of acrylic for armboards.
I dislike acrylic too. I had an acrylic armboard on an Oracle Delphi and my V5 boomed terribly. Maybe a different arm, on a different deck would suit plastic material.
What strikes me is the lack of research into this, you'd think there would be a little list somewhere on the forums outlining good combinations. But I've never seen one. My instinct is that a good 'lossy' board will avoid energy being reflected back up the arm. But it's guesswork really. So many variables.
Incidentally,for what it's worth, SME use heavy brass armboards on the 'series 30' models but compacted aluminium on the 10/20 ranges. I'm told brass is time-consuming to machine.
It depends on the turntable, Andy, and what effect you’re trying to create. On some T/Ts, metal arm-boards work a treat :)
Marco.
Prolly true mate, but l do believe SpeedySteeve may be on to something with his Ebony arm boards- having said that my Gert Pedersen armboard tweak on my Gyro lifted performance a good deal l have to say.:)
hifi_dave
26-02-2015, 17:47
It's horses for courses. Various arm and turntable combinations need different armboard materials. There is no right or wrong, it's a matter of taste.
There is widespread misunderstanding/confusion regarding material choice for armboards. For example, wood is an extremely varied material under a rather misleading banner - birch ply is very different to ebony... If you look at the stiffness to mass ratio of ebony it is much closer to aluminium than any softwood. Also, how the materials are used makes as much difference as what materials are used.
Exactly, but to my ears with ebony, you get the rigidity of aluminium without any other the often nasty, ‘peaky’ resonances of metal….. On a Techy, wooden armboards definitely sound more ‘musical’.
Here’s an example of one of Steve’s beautiful solid-ebony armboards, fitted to Rich B’s Techinics SL-1210, with an Audio Technica AT-1005mkII arm :
http://i727.photobucket.com/albums/ww272/speedysteve7/hifi/Armboard/IMG_5604.jpg (http://s727.photobucket.com/user/speedysteve7/media/hifi/Armboard/IMG_5604.jpg.html)
http://i727.photobucket.com/albums/ww272/speedysteve7/hifi/Armboard/IMG_5613.jpg (http://s727.photobucket.com/user/speedysteve7/media/hifi/Armboard/IMG_5613.jpg.html)
Awesome! :)
Marco.
ive bought some ebony today to try on my AR turntable,should be better than the stock mdf :)
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