Paul,
I think if over done it has the potential to cause more friction laterally placing all that weight under the bearings. It's a delicate balance, but from what I gather this Clearaudio arm is only a prototype at this point and is not a product as of yet. Whether you place the mass under the bearings or outwards depends on the vertical effective mass your aiming for.
Colin
I think if over done it has the potential to cause more friction laterally placing all that weight under the bearings. It's a delicate balance, but from what I gather this Clearaudio arm is only a prototype at this point and is not a product as of yet. Whether you place the mass under the bearings or outwards depends on the vertical effective mass your aiming for.
Colin
Colin & Paul,
I've been working on the low frequency resonance problem off and on for some time now and really getting nowhere. Going to the 2 tube design with the L angle pretty much eliminated the actual glass tube resonances. The low frequency resonance remained almost as bad as ever. Even went as far as extending the L arm to the other side of the record and making a support for the far end of the L. This killed the low resonance. There were still some less intense higher frequency ones. These tones I'm fighting really take some impact to excite. Tapping anywhere on the tube/L assembly with a pencil or the stylus cleaning brush makes a noise, dull thud sort of noise which dies out instantly. It is pretty conclusive that the condition can be controlled with double ended support of the L. It is even no greater effort to change records. I still like the single ended design better, much cleaner looking.
Next I used my support post up between the L mounting block and the platter. The support post has a sharpened screw in the top end for tensioning it against the L. This has made a real improvement but not an entire cure. I'm beginning to realize that my real problem is with the single post mounting. Will have to try some mount with multiple bolts and locking nuts like what you fellows are using. Perhaps replacing the 3/8" rod with a big fat aluminum cylinder will do it. Back to the workshop.
As I mentioned in earlier postings I feel that the carriage weight of 14.5 grams was a bit too light. What shows up with the resonance testing is that there seems to be a rattle when tapping that appears to be the carriage bouncing on the glass tubes. I think I can detect a similar but quieter sound on a piano recording. There was a piece of 1/4" dia, thick wall, brass tube
about 1.5" long and weighing 6.5 grams in the scrap box. This was fastened to the underside of the arm wand directly below the bearing mount.
This appears to have cleaned up the "rattle" and being below the wand contributes to the low slung CW effect. Slinging the CW as low as I can get it makes no apparent change in the sound with the brass tube there. My total weight of the carriage with cart and all bits attached is now at 26 grams. Can't describe how the sound has changed, one just feels more involved, more "there", more better.
Rgds,
BillG
Bill,
You need to stop using the arm as a drum
, no matter what we do if we tap such a sensitive device we will pick up sound, I'm happy as a clam just to have no overhang on resonance. I am not having this same LF resonance with the L, maybe its the way I've mounted the whole shebang?.
Colin
You need to stop using the arm as a drum
, no matter what we do if we tap such a sensitive device we will pick up sound, I'm happy as a clam just to have no overhang on resonance. I am not having this same LF resonance with the L, maybe its the way I've mounted the whole shebang?.Colin
One addition, as it has been shown loading the bearing up to a degree which is good. Besides the vertical benefit of placing the weight at the cartridge and the far rear of the arm wand, also it is a lot harder to excite weights at the extreme vs is centrally located weight near the pivot. Think of a pole with the dominant mass located at your palm, its much easier to twist, right?, now split this and place it at each end of the pole, much harder to twist into motion so in reality this will place a more stable load upon the bearings rather than massing up directly below the bearings.
Just my 2 Canadian cents
Colin
Just my 2 Canadian cents
Colin
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Bill,
You need to stop using the arm as a drum
Colin
Colin, (both posts)
Thanks for comments. This thing is coming together and I'm beginning to really see what is going on. I'll shift the weights to the ends of the wand, about 3 grams on each end should do it. Your illustration was good.
Last night after my posting I took a chunk of putty about the size of a golf ball and molded it tightly around the 3/8" support rod making good contact between the arm block and the mounting base. That pretty much tamed the lo freq res. I'd done that before going to the L and had no significant results. There was just too much else going on. Cleaning up with the L configuration has made it possible to evaluate the putty blob. So I think I'm onto something. Putty blobs are not the solution, but they do point the way. I wonder if Cantus and now the new Clearaudio have or had any such problems.
ChrisG, On the Cantus there is a round disk that mounts to the plinth as does my arm. A smaller cylinder about 1 inch or more in dia sprouts up from the larger base disk and extends up to the main block. Do you remember if this cylinder fastens to the main block or just has a smaller rod that adjusts up and down to position the height af the arm? Be nice to know how Cantus and now CA handle this.
RGDS to all,
BillG
Hello Bill
I remember the Cantus well and in the form I have my current arm, this outperforms it quite significantly.
The mounting base and support pillar were about as crude as you could get. The circular base was glued to the top plate although I modified it by drilling three holes to enable it to be securely bolted to the arm board. There was no way of adjusting the glass rod to ensure it was parallel to the record. My mod at least offered some form of adjustment in this respect.
The arm pillar which mated with the main block was the cheapest tube of aluminium you could imagine-just hollow with no damping. This then entered the block and was secured by a set screw. Arm height was adjusted simply by lifting up or dropping down the main block and tightening the screw. As I said, very basic.
A few more words about the Cantus-no damping whatsoever. The glass tube was simply glued into the housing and rang like a bell. Seems damping wasn't even on the radar with this one. Wire and cartridge tags were cheap and nasty.
As I've said before-you didn't get much for your £650.00 plus.
Regards
Chris
I remember the Cantus well and in the form I have my current arm, this outperforms it quite significantly.
The mounting base and support pillar were about as crude as you could get. The circular base was glued to the top plate although I modified it by drilling three holes to enable it to be securely bolted to the arm board. There was no way of adjusting the glass rod to ensure it was parallel to the record. My mod at least offered some form of adjustment in this respect.
The arm pillar which mated with the main block was the cheapest tube of aluminium you could imagine-just hollow with no damping. This then entered the block and was secured by a set screw. Arm height was adjusted simply by lifting up or dropping down the main block and tightening the screw. As I said, very basic.
A few more words about the Cantus-no damping whatsoever. The glass tube was simply glued into the housing and rang like a bell. Seems damping wasn't even on the radar with this one. Wire and cartridge tags were cheap and nasty.
As I've said before-you didn't get much for your £650.00 plus.
Regards
Chris
If you want to increase the mass of carriage every added gram should be used to improve the structure of the carriage as well and not be there to just increase mass. The putty is a great idea as you can keep adding bits until you start getting tracking problems. You'll then know exactly how much mass you can use.
You've already shown how making the track/rails more rigid and better damped has improved sound quality. The most difficult source of vibration in a turntable to control is that created at the stylus/record interface. The carriage/armtube is much closer to the stylus than the rail. Improvements made here will have a greater positive effect than a similar improvement in the rail.
A thicker more rigid armtube is an obvious way to increase mass. The increased mass of a thicker armtube will increase effective mass. To reduce this a heavier counterweight set closer to the yoke will be required. This will enable you to shorten the rear section of the armtube which will further improve the carriages resonance properties.
Niffy
You've already shown how making the track/rails more rigid and better damped has improved sound quality. The most difficult source of vibration in a turntable to control is that created at the stylus/record interface. The carriage/armtube is much closer to the stylus than the rail. Improvements made here will have a greater positive effect than a similar improvement in the rail.
A thicker more rigid armtube is an obvious way to increase mass. The increased mass of a thicker armtube will increase effective mass. To reduce this a heavier counterweight set closer to the yoke will be required. This will enable you to shorten the rear section of the armtube which will further improve the carriages resonance properties.
Niffy
it appears to me as this design contains some interesting details for us ! massive support base as well as resonance controlled carrier made out of plywood / alu sandwich . both are vital for getting things disscussed here under controle . at least to a serious degree .
I can't commend on this yet , but my gut feeling says it's a good thing to pay attention too .
I'll try the 2 pillar support , along with the sandwich construction to figure if I can happily play some drum parts on the carrier during playback just kidding guys .. doing some drum play could bring one some further .. just using it as an instrument for improving things regarding dampening .
THX for all the info and thoughts guys !
Paul
I can't commend on this yet , but my gut feeling says it's a good thing to pay attention too .
I'll try the 2 pillar support , along with the sandwich construction to figure if I can happily play some drum parts on the carrier during playback
just kidding guys .. doing some drum play could bring one some further .. just using it as an instrument for improving things regarding dampening .THX for all the info and thoughts guys !
Paul
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Niffy,
I hear you, but in all honesty a .220", 6" long carbon fiber wand is very stiff. The t mount is 10mm thick polycarbonate, this is very rigid. My goal now is to try out a wand with aluminum headshell, more mass at the extremes and distributed cleverly
Colin
Outriggers
Niffy,
I hear you, but in all honesty a .220", 6" long carbon fiber wand is very stiff. The t mount is 10mm thick polycarbonate, this is very rigid. My goal now is to try out a wand with aluminum headshell, more mass at the extremes and distributed cleverly
Colin
I agree, your armtube will be very stiff. Probably as stiff as any arm available commercially. The difference between your tube and say a 10mm tube will appear to be negligible if gently flexed by hand. The arms function is to keep the cartridge as stationary as possible relative to the neutral axis of the record groove. The difference in the amount that the cartridge moves between a good arm and an excellent arm would be measured in fractions of a nanometer.
However at low frequencies, well below the arms rf, arm rigidity plays only a small roll. Here it's the mass of the arm that matters. It's much harder to shake a heavy object than a light one hence the improvements in sound you've noticed with the slightly heavier arm.
You are doing a fantastic job in developing this arm. As you are tweaking every aspect of the design to squeeze every last bit of information from the groove this might be a further avenue for experimentation.
Niffy
Hi Chris, and Colin,
Chris,
Thanks for the information. It is clear that my arm also is way above Cantus already. I just replaced the smooth but tight fitting arm pillar rod with a threaded 3/8" carriage bolt. Drilled the main block clear through so the bolt could be locked in with a nut well tightened on the under side. the bolt is 4" long and fitted with 2 stout nuts. They provide precise and easy adjustment of carriage height. The existing grub screw locks the setting and once cightened well, the adjusting nut is further snugged up and the one above it provides additional tension. As before, the 4 pointed screws in the base adjust for arm leveling.
Colin,
This tightening up of the whole mounting system has done a fine job of controlling the low frequency resonance. I think you have heard the last on that score.
Thanks for the help,
BillG
Niffy,
I hear you, but in all honesty a .220", 6" long carbon fiber wand is very stiff. The t mount is 10mm thick polycarbonate, this is very rigid. My goal now is to try out a wand with aluminum headshell, more mass at the extremes and distributed cleverly
Colin
Headshell above carbon armlevel ? getting the diamond tip closer to pivot level ?
THX
Paul
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New here, think I've read it all, and was wondering if you guys thought about putting a bearing on both ends of the glass rod to help reduce VTF variations? Didn't see a discussion on this but could have missed it.
I have a full shop in my basement, multiple mills and lathes with CNC on a number of them and have been kicking around an air bearing vs this setup for a micro seiki I have as a secondary table. I have a TNT MK IV as primary with the longer JMW arm. Right now I am leaning towards air using low pressure, high volume but this design is interesting with trade offs.
I have a full shop in my basement, multiple mills and lathes with CNC on a number of them and have been kicking around an air bearing vs this setup for a micro seiki I have as a secondary table. I have a TNT MK IV as primary with the longer JMW arm. Right now I am leaning towards air using low pressure, high volume but this design is interesting with trade offs.
Thats what I did right from the get go Bill when I mounted the arm to the Rega.
Used a brass 7/8" threaded rod and compressed the whole thing between the plinth.....see the pic.
The Rega just didnt do it for me so I've since mounted this arm back to my DD.
Used a 1/2" threaded rod and made a hole thru the DD plinth and sandwiched it on.....its excellent.
I have to look for a better table now......saving pennies.
At the headshell. Better stability at the cartoutriggers , controlling what ? curious
THX
Paul
Just figured if you were going to add weight at the headshell. Do you remember the grace carts? They looked like long horn steers.
this is getting fine tuned now
To all,
Just made a new armwand with a 5 g solid alu block headshell, a substantial improvement !. It is 3/4" w 5/8" h and 1/4" deep, and the cart mounts to the underside 3/4" x 1/4" section . I'll post pics later, had quick listen and tracking is even more improved noticed on the first 10seconds easily.
Colin
To all,
Just made a new armwand with a 5 g solid alu block headshell, a substantial improvement !. It is 3/4" w 5/8" h and 1/4" deep, and the cart mounts to the underside 3/4" x 1/4" section . I'll post pics later, had quick listen and tracking is even more improved noticed on the first 10seconds easily
.Colin