most important aspect of a turntables design

[joessportster]

i have a notingham mentor (was once there top table) however i was never impressed by there plinth design ( a little cheesy i thought, 1.5" thick mdf painted with solid feet and no leveling adjustments ) so i decided to hopefully improve upon there product................

as i see it a tables most important features are speed stability (they have that down cold), platter and bearing (they also have that down) then comes isolation and mass both of which help releave problems with vibration that can cause terriable feedback and resonance issues these last 2 are where it seems that nottingham missed the mark a bit

so my plan was to make a much more massive plynth, isolate the motor and arm from that plynth and employ isolation feet on all 3 to further help with vibration and dissapation of same

i have included a pic of the work in progress so far sure seems to have done the trick tell me what you guys think

[seti]

That looks really cool. Can't wait to see it finished. What veneer are you considering?

I'm awaiting the final plinth for my 301 should be soon. I've been listening to the Hagtech Bugle you gave me with my 301 12inch Jelco and Orotofon 2M Blu. So far so good

[The Dude]

were did you come up with the idea to build that, as far as plans go. That looks like fun, nice looking table so far.

duder

[joshnich]

Joe

Looks fantastic. Question: where is the motor?

Josh

[seti]

For those unfamiliar with what it looked like before.

Yeah where is the motor now?

[joessportster]

seti: i was going to use ebony but its to dark i think, so now i am thinking about a maple burle or birdseye havent really made up my mind i want to get a piece wide and long enough to only have one seam on the back of the table, glad the bugle is still doing what you want it to..........

duder : i didnt have a set of plans just kinda played with the idea and kept expanding on it through trial and error, cutting the 6 circles to mate togeather was fun i used a router with a home made jig that held the router at a fixed distance and just swung it around in circles cutting a little with each pass good thing about this method is the center of each disc was marked by my jig.

joshnich: seti: the motor sets behind the table on another stand, the stands were a bit of a task to figure out as well, i took schedule 40 pvc cut it to length plugged the bottom with fiberglass bondo, filled with BB's (to add weight) then capped the top as well with fiberglass bondo, know i want to apply the same veneer to the pvc tubes as i do the plynth for a nice uniform appearance.

it is a fun little project and the table is alot more flexiable now in regards to set-up and i beleive it sounds better as well..........

Joe

[greg928gts]

Oh, I see.

Greg

[LarryC]

For those unfamiliar with what it looked like before.

Seti, I only get a red X, rather than your picture.

[seti]

For those unfamiliar with what it looked like before.

Seti, I only get a red X, rather than your picture.

Some site didn't like linking. Here is another. It might not be the exact mento as there were a couple versions.

[joessportster]

here is a pic of the B-4 on my actual table

[LarryC]

Joe, I think A.J. Conti's (Basis Audio president) tech papers on turntable design give an interesting picture of what he thinks are important engineering considerations (wrapped in a hyperventilating writing style). These link to his tech pdf's on TT design and suspension: http://www.basisaudio.com/docs/tbl_2001_specs.pdf and http://www.basisaudio.com/docs/SuspensionTP.pdf

[Edit] Conti's engineering includes focusing on precision manufacturing, very close tolerances, resonance control, etc.

[joessportster]

thanks for the links larry i will give them a look

Joe

[kevinmi]

I see the problem already. There are big rubber bands hanging off your tonearm. Everyone knows that it is much better to place pennies on the headshell for extra weight. Seriously though, I've done some plinth modifications, and I think you are on the right track. As a matter of fact, I have a very similar project to yours ongoing right now using a direct drive JVC QL-7 turntable. Here's an idea I'm kicking around- splitting the plinth and using springs in between the upper and lower half, like the Wilson-Benesch turntables. Here's a pic of the plinth I did this summer for my JVC QL-5.

[joessportster]

hey kevin nice looking table / plynth, i thought about suspension type plynths but my platter weighs in at over 70 pounds and with that amount of weight i figured it would be very hard to get right, the design i came up with has been the easiest i had to level

Joe

[artto]

Be careful what you ask for. Depending on the turntable, and especially the turntable/arm/pickup combination, heavy massive support systems are not necessarily the best solution for isolation.

I used to have two turntable racks, both loaded with more than 300LBS of soild cement blocks floated on closed cell foam like thick weather striping. The individual blocks were about 9x18x2. I combined them together in combinations of 2 or 3, or 2+3 for 5, and were "glued" together with caulking/silicone to help damp any resonances.

http://community.klipsch.com/forums/t/19799.aspx?PageIndex=1

It turns out the best solution was to simply use a decoupled lightweight wood shelf.

And there's another issue too. What kind of floor is the turntable/table sitting on? If it's on solid ground (ie: concrete floor/slab on ground) you might be ok. If its on a "standard" residential floor with joists, that floor is going to bounce and have give which will only aggrevate the problem. Also, if the table is in or near a room corner it will all be for naught anyway as the bass build up in the room corners will excite the tonearm/pickup assembly which can cause excessive bass or even mistracking regardless of how massive you make the support system.

Other than that, what you're doing looks like it's going to look pretty cool. Hope it works out for the better.