Powerglide Posted August 19, 2018 Share Posted August 19, 2018 (edited) I've been contemplating building a dampening table for one of my TT's for some time, I'm in an older two story double brick house with suspended timber floors, my music room is upstairs and I get a fair bit of footfall noise reach the cart on approach when changing an album which suggests I'm getting other unwanted vibration during play. The TT I'm referring to is a Sansui SR 525 and at the time of contemplation had a Denon DL 110 fitted, a few months back I swapped out the Denon for a Rondo Bronze which dramatically reduced the footfall noise. As the 525 is my second string TT it kind of gets what's left thrown on it, a recent phono purchase saw me needed the Rondo's higher output and ment an Ortofon Rohmann ended up on the Sansui, this tightened things up even more and spookily closed the gap between my TT's (pre new phono) I still think there is room of improvement with a "Dampening" table, I won't say isolation with the fear of getting chastised but that is the goal. Design: MDF sandbox on spring type feet, I've put a hollow rubber tube on the edges to contain the sand and center the TT platform from hitting the sandbox Lucky for me I have a few odd tools in the carport cutting the board to size on Elmo "that tickles"I'm going to paint finish the table so I use a satin finish melamine, this is 10 x smoother than raw MDF and negates the need for multiple high build undercoats, I mitre all joints, this increases the surface area of the joint and the bond is MDF to MDF, butt joints alway crack. cutting the mitre's, bit hard to cut and photo, blade is on a 45, I set up the rip fence on the waste wood side so every cut becomes the same the rubber seal is used in timber door frames as a weather seal, it fits into a 2.5mm groove which is close to the blade thickness cutting the grooves 5mm deep components ready for assemblyI lay them out on a flat bench and tape together with a good quality masking tape turn over, glue the joints and fold together, tape the corners, no mechanical fixingspeel the tape off the next day, I added a pencil round on the TT platform this softens the look and gives the paint something to stick to, if you left it sharp the paint will chip I just gave the sand box edges a heavy aris, not seen but I'm going to paint anywaybeing a prototype I realised I could improve on the design. Do away with the rubber top seal, which I only put in to contain the sand, and add an additional board to the underside of the platform. This means I can lower the sand level and reduce the spill risk, I don't even really need the side seals.lucky for me I have a spray booth, but forgot to take action photos. I went with full gloss piano black and they came out mint.the feet should get here this week and I'll put it to the test, no equipment, just ears I have a CNC router and wish I'd engraved the Sansui logo in the face, next time! I may also make another platform in Walnut or American Oak I'll post a pick of the set up unit once the feet get here rubber seal Edited August 19, 2018 by Powerglide Rubber pic 9 Link to comment Share on other sites More sharing options...
Citroen Posted August 19, 2018 Share Posted August 19, 2018 Looking very sleek! Is the idea of the tt platform just to hide the feet? Otherwise most sandboxes just use the insert on top of the sand as the platform. Link to comment Share on other sites More sharing options...
BATMAQN Posted August 19, 2018 Share Posted August 19, 2018 Nice work mate you have skills and good tools hope it works nicely for you. Link to comment Share on other sites More sharing options...
Powerglide Posted August 19, 2018 Author Share Posted August 19, 2018 2 minutes ago, Citroen said: Looking very sleek! Is the idea of the tt platform just to hide the feet? Otherwise most sandboxes just use the insert on top of the sand as the platform. Yeah, hides everything and gives a floating look nice win last night Cliff, I was at the game and a bit nervous at half time Kia Kaha Link to comment Share on other sites More sharing options...
Powerglide Posted August 19, 2018 Author Share Posted August 19, 2018 32 minutes ago, BATMAQN said: Nice work mate you have skills and good tools hope it works nicely for you. Thanks Seb, told you I'd be trying something, just took 6 months. From what I've learnt recently it was bad advice from me on cart choice for your 929, not that you took it! I have a feeling a lower MC would be bettter, what did you end up doing? Link to comment Share on other sites More sharing options...
perth_artist Posted August 19, 2018 Share Posted August 19, 2018 Looking good, excellent craftsmanship Quite the workshop you have ! Looking forward to seeing how it looks all finished. Link to comment Share on other sites More sharing options...
wasabijim Posted August 20, 2018 Share Posted August 20, 2018 (edited) can't wait to see the outcome Edited August 20, 2018 by wasabijim Link to comment Share on other sites More sharing options...
Powerglide Posted August 27, 2018 Author Share Posted August 27, 2018 OK the feet arrived Friday, same as @Happy put on the chopping boards, originally I was looking at sorbothane hemispheres but heard the good wood on the springs. They were a little taller so I routered them in 12mm so the cover would come down nice and low set up time: I used a premium silica sand I had left over from an epoxy floor, the granules are a bit larger than the norm with the smaller particles sifted out. Should settle in quicker and leave more air between the grains? lid on I levelled with a laser, probably need to check in a week or twoRohmann digging out Beck's Morning Phase definitely reduced the footfall tenfold got a bit of experimenting to do, give the dust cover a good tap and the needle jumps a track, easy fix don't tap it! I took out the centre spring on each foot as suggested maybe could go a few more to get it on the hover verge. SQ? hard to tell this early on, I only use this TT one record in ten so I'm not that in tune with it. I'll see if I can hear a difference with the Rega in a month or so. Fool for your stockings is sounding mighty fine 7 Link to comment Share on other sites More sharing options...
perth_artist Posted August 27, 2018 Share Posted August 27, 2018 You should be proud of yourself, it looks amazing, well worth all the effort. Link to comment Share on other sites More sharing options...
flanders Posted August 30, 2018 Share Posted August 30, 2018 Wow, nice work! With those skills and workshop, you should make a whole turntable! Link to comment Share on other sites More sharing options...
Powerglide Posted September 4, 2018 Author Share Posted September 4, 2018 Thanks for the kind words, I'd like to refurbish a set of classic speakers one day. always too busy doing other people's shyt. Not sure of any sonic benifit of the sand box appart from fixing the footfall speaker wobble, truth is the biggest plus has been changing an album is easier on the back! Link to comment Share on other sites More sharing options...
Peter_F Posted November 23, 2019 Share Posted November 23, 2019 A good effort but the sandbox use in hifi is IME useless. IME you would have been better off attaching the decoupling feet directly to the turntable. 1 Link to comment Share on other sites More sharing options...
THOMO Posted November 23, 2019 Share Posted November 23, 2019 28 minutes ago, Peter_F said: A good effort but the sandbox use in hifi is IME useless. IME you would have been better off attaching the decoupling feet directly to the turntable. Yes a great job but Australian Hi Fi tested a range of isolation platforms and found sand boxes did not work..I reckon ditch the sand and replace it with swimming pool noodles cut to length and stood up in the box.Bunnings have them for $2 each so it would be a cheap experiment. Link to comment Share on other sites More sharing options...
Powerglide Posted November 24, 2019 Author Share Posted November 24, 2019 I definitely tighten up the woofer wobble I was experiencing pre sand box, but yes probably just the sprung feet component, which I latter swapped out for hemispherical silicone feet. I get the sand approch, being the air gaps between each grain is the dampening component for wave transfer between the grains. With this in mind I had thought of swapping the sand for shredded or granulated rubber that would also add an absorbtion factor. I couldn't track down where to buy the product, I was thinking something like the recycled shredded tyres they use on equestrian rinks. The closed cell foam may be the go @THOMO Link to comment Share on other sites More sharing options...
Peter_F Posted November 24, 2019 Share Posted November 24, 2019 1 hour ago, Powerglide said: With this in mind I had thought of swapping the sand for shredded or granulated rubber that would also add an absorbtion factor. I'd be careful about creating a problem and then trying to solve it. Upgrading the feet on the TT is the better option IMO. Link to comment Share on other sites More sharing options...
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