MattyW Posted October 11, 2017 Share Posted October 11, 2017 Ok, so I recently sourced a genuine JVC two arm plinth for my JVC TT-71 turntable. I was wondering if anyone knows where in Brisbane I can go to have two new MDF arm boards fashioned? I've the two originals set aside to use as templates. I want to get 6x made up so I can have various arms mounted which I can quickly switch out on the table. I'll end up painting the arm boards in either charcoal or gunmetal grey with a hammertone finish. Link to comment Share on other sites More sharing options...
andyr Posted October 11, 2017 Share Posted October 11, 2017 Why would you want to have them made up out of MDF? (I can't imagine a worse material.) IME, MDF will suck the life out of the music - ply (particularly birch ply) would deliver a better sound. Andy 1 Link to comment Share on other sites More sharing options...
MattyW Posted October 11, 2017 Author Share Posted October 11, 2017 (edited) I had thought that it would prevent external vibrations from affecting the sound. If birch ply is the go then that's what I'll request. Just trying to find out who can do it locally. Edited October 11, 2017 by MattyW Link to comment Share on other sites More sharing options...
andyr Posted October 12, 2017 Share Posted October 12, 2017 3 hours ago, MattyW said: I had thought that it would prevent external vibrations from affecting the sound. Sorry can't see the connection between "preventing external vibrations from affecting the sound" (a laudable aim) and MDF? It seems to me that something that is damped and heavy (like slate) might do a better job on your solid plinth than something that is damped and light (like ply)? 3 hours ago, MattyW said: If birch ply is the go then that's what I'll request. Just trying to find out who can do it locally. Any cabinet maker should be able to do it (with birch ply). As I mentioned above - possibly slate would be better, as you don't have a sprung TT. Another option - the absolute other end of the scale, in terms of weight! - would be CF-composite ... for which you would have to go to a high-tech boat builder! I would've thought Brissie/ the Gold Coast must have a few? Construction would be: 1mm CF skins top & bottom balsa in the middle. Andy Link to comment Share on other sites More sharing options...
MattyW Posted October 12, 2017 Author Share Posted October 12, 2017 MDF is vibration deadening, hence the reason many manufacturers opt to use it for plinth material..... As well as being cheap. Seems like a natural choice, not to mention any number of MDF arm boards that are ready made and for sale for other tables. Seemed a nobrainer. I'll see if I can get in touch with a cabinet maker. Rosewood would be optimal as I've had good results with that in the past on my previous Ariston RD110 SL table. 2 Link to comment Share on other sites More sharing options...
EV Cali Posted October 12, 2017 Share Posted October 12, 2017 (edited) IMO if you are looking for material that will not resonate and pass on vibration, a dense, board like MDF would be better than ply or solid timber. Acoustic guitars have solid timber or ply tops ,not MDF ,for this reason. Either way what you are trying to achieve is quite simple. A strip of material docked to length six times with a round hole in each . Work out the sizes you need and pop in to a local joinery works with your sample and ask nicely if they can help. The job is so small the personal touch of going in may help. You could try this one https://www.allkind.com.au/joinery/ Edited October 12, 2017 by EV Cali 1 Link to comment Share on other sites More sharing options...
MattyW Posted October 12, 2017 Author Share Posted October 12, 2017 (edited) 6 minutes ago, EV Cali said: IMO if you are looking for material that will not resonate and pass on vibration, a dense, board like MDF would be better than ply or solid timber. Acoustic guitars have solid timber or ply tops ,not MDF ,for this reason. Either way what you are trying to achieve is quite simple. A strip of material docked to length six times with a round hole in each . Work out the sizes you need and pop in to a local joinery works with your sample and ask nicely if they can help. The job is so small the personal touch of going in may help. You could try this one https://www.allkind.com.au/joinery/ Awesome, thanks for that. I've a week off work coming up. I'll visit them then. They're quite close to my place too which is great So, wouldn't that make MDF suitable just keeping any vibration within the arm and cartridge itself? As you can tell I don't really know about this. Edited October 12, 2017 by MattyW Link to comment Share on other sites More sharing options...
EV Cali Posted October 12, 2017 Share Posted October 12, 2017 (edited) 7 minutes ago, MattyW said: Awesome, thanks for that. I've a week off work coming up. I'll visit them then. So, wouldn't that make MDF suitable just keeping any vibration within the arm and cartridge itself? As you can tell I don't really know about this. Yes Matt that's exactly what I am saying. You are correct ,if you want a dead material that will not transmit vibrations MDF is better. This is also the reason speaker cab's are made of MDF not ply or solid timber. Guitar sound boards are made of ply and solid timber precisely because they do resonate and for a guitar ,that is what is required. Edited October 12, 2017 by EV Cali 1 Link to comment Share on other sites More sharing options...
Full Range Posted October 12, 2017 Share Posted October 12, 2017 @MattyW Go to “ Wood N You” in Coopers Plains I get them to cut my cabinet panels They also did my Garrard 401 plinth Or I may be able to use or lend my router if you are keen for some DIY 1 Link to comment Share on other sites More sharing options...
MattyW Posted October 12, 2017 Author Share Posted October 12, 2017 I'll give Allkind a try as they're close to home (13 minutes drive according to Google Maps) and keep Wood N You in mind if they're not able to help. If they can use MDF that's what I'll ask for, otherwise I'll go fore Rosewood as that's what was used in the Ariston in the past and that table sounded lovely. I'm looking forward to being able to change between my Fidelity Research FR-24 & 54, Denon DP-70M arm and Mayware Formula 4. I'm intending to use the Mayware for high compliance carts and use one of the Fidelity Research or the Denon arm for medium and low compliance carts. I'm rather hoping that the Denon arm will have comparable performance to the FR arms as I like the idea of autolift at the end of each side..... Means when tired I don't have to resort to digital playback for fear of falling asleep 1 Link to comment Share on other sites More sharing options...
Guest guru Posted October 12, 2017 Share Posted October 12, 2017 56 minutes ago, EV Cali said: Yes Matt that's exactly what I am saying. You are correct ,if you want a dead material that will not transmit vibrations MDF is better. This is also the reason speaker cab's are made of MDF not ply or solid timber. Guitar sound boards are made of ply and solid timber precisely because they do resonate and for a guitar ,that is what is required. Not all speaker cabinets are made of mdf. Quite a few reasonable sounding ones are using ply for a number of sonic reasons. Link to comment Share on other sites More sharing options...
andyr Posted October 12, 2017 Share Posted October 12, 2017 1 hour ago, EV Cali said: This is also the reason speaker cab's are made of MDF not ply or solid timber. Spkr cabs are made from MDF for several reasons - none of which have anything to do with "it creates the best sound possible, for the speaker": it's cheap it's easily machinable it won't warp - in the case of large cabinet panels. 28 minutes ago, guru said: Not all speaker cabinets are made of mdf. Quite a few reasonable sounding ones are using ply for a number of sonic reasons. And some expensive speakers use even more esoteric materials. (I'm thinking the B&W "Nautilus".) Andy Link to comment Share on other sites More sharing options...
EV Cali Posted October 12, 2017 Share Posted October 12, 2017 29 minutes ago, guru said: Not all speaker cabinets are made of mdf. Quite a few reasonable sounding ones are using ply for a number of sonic reasons. Agree It was meant as a generalisation. I could add the word ,generally, if you like. 4 minutes ago, andyr said: it's cheap it's easily machinable it won't warp - in the case of large cabinet panels. Plus a forth dot point , because it is a dense material that does not resonate easily. There are reasons not to use MDF though. One being it is easily damaged. I made some large PA speaker and I made these out of 25mm ply, as they were going to be moved in and out of a van and in to venues regularly and needed to be strong and tough 1 Link to comment Share on other sites More sharing options...
MattyW Posted October 12, 2017 Author Share Posted October 12, 2017 I don't see that being a negative where arm boards are concerned though as I don't see them actually coming into contact with anything. On the other hand it is possible that they could crack if I over tighten the screws..... I'm leaning towards rosewood now for this reason. Link to comment Share on other sites More sharing options...
Happy Posted October 12, 2017 Share Posted October 12, 2017 4 minutes ago, MattyW said: I don't see that being a negative where arm boards are concerned though as I don't see them actually coming into contact with anything. On the other hand it is possible that they could crack if I over tighten the screws..... I'm leaning towards rosewood now for this reason. wouldn't that shrink/warp easily? Link to comment Share on other sites More sharing options...
MattyW Posted October 12, 2017 Author Share Posted October 12, 2017 Not sure I can cover everything. What material does everyone suggest? Link to comment Share on other sites More sharing options...
Guest guru Posted October 12, 2017 Share Posted October 12, 2017 17 minutes ago, MattyW said: I don't see that being a negative where arm boards are concerned though as I don't see them actually coming into contact with anything. On the other hand it is possible that they could crack if I over tighten the screws..... I'm leaning towards rosewood now for this reason. Rosewood is a very generic name to a timber supplier, you would be met with a questioning look as to what rosewood are you referring too. Try to narrow the field and you will find they all have different properties which may be beneficial to the specific requirement. Link to comment Share on other sites More sharing options...
EV Cali Posted October 12, 2017 Share Posted October 12, 2017 (edited) 28 minutes ago, MattyW said: I don't see that being a negative where arm boards are concerned though as I don't see them actually coming into contact with anything. On the other hand it is possible that they could crack if I over tighten the screws..... I'm leaning towards rosewood now for this reason. Manufactured boards are less likely to crack because they have no grain or ,as with ply, the grain of each sheet runs in the opposite direction. Screw holes near the edge of solid timber has a risk of causing splits. Especially if you are going to swap the arm boards around. You were correct to begin with, use MDF. Edited October 12, 2017 by EV Cali 2 Link to comment Share on other sites More sharing options...
metal beat Posted October 12, 2017 Share Posted October 12, 2017 Plywood just like the plinth you are putting your table into. Link to comment Share on other sites More sharing options...
Guest Muon N' Posted October 12, 2017 Share Posted October 12, 2017 As usual my thought on this would be.....wait for it.....Bamboo Yeah, I'm a fan Not that I have ever had to make or use an arm board Link to comment Share on other sites More sharing options...
MattyW Posted October 12, 2017 Author Share Posted October 12, 2017 Bamboo would be interesting if they can do it..... I like that suggestions Link to comment Share on other sites More sharing options...
EV Cali Posted October 12, 2017 Share Posted October 12, 2017 6 minutes ago, metal beat said: Plywood just like the plinth you are putting your table into. The plinth looks like layers of chipboard to me. Bamboo, ply , MDF would all be ok . Resonance in is not likely to be an issue with the dimensions of the arm board. 1 Link to comment Share on other sites More sharing options...
Wimbo Posted October 12, 2017 Share Posted October 12, 2017 22 minutes ago, EV Cali said: You were correct to begin with use MDF. I agree with this. Isolation isolation isolation. Then again, any energy that is stored in the cartridge/tonearm is unwanted and needs to be dissipated quickly. So, does MDF act as a sink in this situation? I'm not a mechanical engineer, so cant answer this. 1 Link to comment Share on other sites More sharing options...
swervyn Posted October 12, 2017 Share Posted October 12, 2017 ok, so have googled what an arm board is and it looks like just a board that the tt arm screws to? does it have to be a certain thickness to fit flush into those rebates? Would of thought thickness would be a good place to start to work out best material, ie: mdf doesnt come in 22mm thickness and if you plane one side you lose the structural integrity of the board and it will curl up Link to comment Share on other sites More sharing options...
MattyW Posted October 12, 2017 Author Share Posted October 12, 2017 (edited) My understanding is that MDF isolates vibration though doesn't damp it at all. So vibration from the cart would remain in the arm, which I'd have thought is ideal for sound reproduction..... I do like the idea of bamboo though. If the armboard is 1 or 2mm thicker than the stock arm boards that should still look fine, and will likely help with the 6mm platter mat I'm using.... It's a little thicker than stock Edited October 12, 2017 by MattyW Link to comment Share on other sites More sharing options...
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