I've got to hand it to PDR, good job and excellent job on proof of concept on this design. With the two glass tubes being rounded edges its a much better pivot than a V shape 
. Now this can be honed substantially, currently designing a system which the arm won't fall off at all. This bearing is not as good at tracking extreme warps as the 4 bearing system,but who would play those anyways. PDR, give yourself a pat on the back fellow Canadian .
Colin
. Now this can be honed substantially, currently designing a system which the arm won't fall off at all. This bearing is not as good at tracking extreme warps as the 4 bearing system,but who would play those anyways. PDR, give yourself a pat on the back fellow Canadian .Colin
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Colin,
You've created something wonderful here. Thanks very much for sharing it. I finally got listening to my prototype and was rather mesmerized last night.
Bill, PDR,
I tried some quick damping efforts on my single glass tube. I shaved the corners off a 1/4"x1/4" piece of balsa wood. It lowered the tube's resonance and changed the sound a bit, but I'm not sure I like it better. Will try it again though.
I also wrapped a layer of electrical tape around a length of carbon fiber tube and stuffed it down the glass. It killed the resonances all together. It also made a weird change to the sound stage.
I like that double tube idea. Are they pressed against each other, or is there a gap?
Hugh
You've created something wonderful here. Thanks very much for sharing it. I finally got listening to my prototype and was rather mesmerized last night.
Bill, PDR,
I tried some quick damping efforts on my single glass tube. I shaved the corners off a 1/4"x1/4" piece of balsa wood. It lowered the tube's resonance and changed the sound a bit, but I'm not sure I like it better. Will try it again though.
I also wrapped a layer of electrical tape around a length of carbon fiber tube and stuffed it down the glass. It killed the resonances all together. It also made a weird change to the sound stage.
I like that double tube idea. Are they pressed against each other, or is there a gap?
Hugh
Tonight's update:
Emptied the sand from the 2 tubes and filled them with 1000cSt silicone oil. Ringing is much better damped. The severe bass note of the single tube arm is gone and a new note, mentioned earlier to be about an octave higher, seems to be what is left. It is quite well damped, doesn't sit there ringing, just dies out quickly. I'd be much happier if it was just the dull thud. The music is grand and it tracks beautifully. So I guess that is what really counts. Got to pick up some materials and build a well finished example now.
PDR,
Are your tubes just held together with "O" rings or are they glued as well?
Please don't forget that ringing test I requested.
BillG
Hjam,
Many thanks, it has been a labour of love and is just the tip of the iceberg. I also have a phono stage, preamp, and power amp which I've honed over the years with unconventional topology, the result well power amp wise seems Ayre is tapping into also for their most recent offerings.
This vinyl biz is a lesson is resonance control, as a Bill is learning you can't eliminate it but only move it, but the key is where you move it to. IMHO moving it up higher is often detrimental, dependant on frequency to begin with, first we must pinpoint the disturbance. Anything will have a low thud if we tap on it, but which is actually excited by playback?. This seems to be key, Also of supreme importance is turntable isolation, a better test is to tap the shelf on which the table sits on with a still record and needle on the vinyl, at the end of the day it's a balance of truly what our ears tell us is good.
Colin
Many thanks, it has been a labour of love and is just the tip of the iceberg
. I also have a phono stage, preamp, and power amp which I've honed over the years with unconventional topology, the result well power amp wise seems Ayre is tapping into also for their most recent offerings. This vinyl biz is a lesson is resonance control, as a Bill is learning you can't eliminate it but only move it, but the key is where you move it to. IMHO moving it up higher is often detrimental, dependant on frequency to begin with, first we must pinpoint the disturbance. Anything will have a low thud if we tap on it, but which is actually excited by playback?. This seems to be key, Also of supreme importance is turntable isolation, a better test is to tap the shelf on which the table sits on with a still record and needle on the vinyl, at the end of the day it's a balance of truly what our ears tell us is good.
Colin
BILLG
A couple of thoughts on damping the glass tube.
Have you thought of using a sand-silicone fluid mix? This would replace the air in your dry sand test with the damping fluid. As silicone fluid has excellent wetting properties it should be very easy to mix.
Alternatively filling the tube with low modulus silicone sealant might work. This will take some time as the tube will have to be left with the ends open for a week or two to allow the sealant to cure. It would also be difficult to remove the sealant if the test didn't pan out so only try if you have a spare glass tube.
I have a feeling the sand-silicone would work better but without testing this is just a guess.
Niffy
A couple of thoughts on damping the glass tube.
Have you thought of using a sand-silicone fluid mix? This would replace the air in your dry sand test with the damping fluid. As silicone fluid has excellent wetting properties it should be very easy to mix.
Alternatively filling the tube with low modulus silicone sealant might work. This will take some time as the tube will have to be left with the ends open for a week or two to allow the sealant to cure. It would also be difficult to remove the sealant if the test didn't pan out so only try if you have a spare glass tube.
I have a feeling the sand-silicone would work better but without testing this is just a guess.
Niffy
I've got to hand it to PDR, good job and excellent job on proof of concept on this design. With the two glass tubes being rounded edges its a much better pivot than a V shape
Colin
Thanks Colin, its just an idea that seemed to work.
Looking forward to where it goes.
Colin, thanks for the back pat.
Its just something that came up, looking
forward to where it goes.
Bill, I have to apologize.
I just havnt had time to get into my room to muck around this weekend.
I work out of town for 10 days out of 14 and I'm heading out this morning again.
I do get to come back for Wed and Thurs night this week, I'll give the
ringing tests a go then.
The tubes I used are 10mm O.D. and 1.5mm thick.
They are glued together on each end with one small drop of crazy glue.
The tubes are epoxied to the thinner top acrylic plate. The way I have the
thumb screws mounted I can level the tubes length wise and across, just
takes a few minutes.
The acrylic plates are held with a threaded hollow brass 7/8" fitting.
There is a nut on each side of the the plates to hold them steady, and
one on the top and bottom of the Rega. The brushed nickle looking
shaft is actually hollow tubes that covers the brass fittings and give it a finished look.
I'm having a hum issue with the Rega, the DD was dead silent. Will have to see if I can work it out.
Its just something that came up, looking
forward to where it goes.
Bill, I have to apologize.
I just havnt had time to get into my room to muck around this weekend.
I work out of town for 10 days out of 14 and I'm heading out this morning again.
I do get to come back for Wed and Thurs night this week, I'll give the
ringing tests a go then.
The tubes I used are 10mm O.D. and 1.5mm thick.
They are glued together on each end with one small drop of crazy glue.
The tubes are epoxied to the thinner top acrylic plate. The way I have the
thumb screws mounted I can level the tubes length wise and across, just
takes a few minutes.
The acrylic plates are held with a threaded hollow brass 7/8" fitting.
There is a nut on each side of the the plates to hold them steady, and
one on the top and bottom of the Rega. The brushed nickle looking
shaft is actually hollow tubes that covers the brass fittings and give it a finished look.
I'm having a hum issue with the Rega, the DD was dead silent. Will have to see if I can work it out.
Hjam,
Many thanks, it has been a labour of love and is just the tip of the iceberg
This vinyl biz is a lesson is resonance control, as a Bill is learning you can't eliminate it but only move it, but the key is where you move it to. IMHO moving it up higher is often detrimental, dependant on frequency to begin with, first we must pinpoint the disturbance. Anything will have a low thud if we tap on it, but which is actually excited by playback?. This seems to be key, Also of supreme importance is turntable isolation, a better test is to tap the shelf on which the table sits on with a still record and needle on the vinyl, at the end of the day it's a balance of truly what our ears tell us is good.
Colin
Thanks Colin,
Looks like I should be quite happy with what has developed. All along I've been working on the TT, the shelf it is on and so forth. I can now bang on the shelf with my fist, beat up the plinths, do a drum roll with my fingers on the track mount block, all with a record playing at normal volume and hear next to nothing! This is a far cry from where it was a few weeks ago. My only fear was that the normal resonance of the track tube(s) could be excited by vibrations in the system and be detrimental to the signal. Apparently this isn't happening and I can live with it (the resonance) in its highly attenuated state.
Niffy,
Sand/silicone mix was my next step. My 2 tubes are glued together with thick magic glue. Looking at the tubes I can see a magnified image of the glue line and all its smears. Ugly at best. So the yet to be implemented cure was to make the silicone opaque, mix it with sand. It may well work better than the clear oil filler. I'll report.
Rgds to all,
BillG
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pdr, not a problem, actually it works quite well as I constructed it last night, friction is almost non existent!!. With the way I knocked it up the arm simply cannot ever fall off of the mechanism!. This opens up some new mounting ideas. As far as hum is concerned run the wires as much as possible through an alu tube, and the ground the tube .
Colin
.Colin
PDR,
I'll second that one about Duct seal from Moray. Works very well. Rona and HomeDepot sell different brands. After a decade, one of them dries out quicker, but I can't recall which is which. I can look if your curious.
Colin,
I found some of those threads on power amps. Interesting stuff.
I think I'm about to order an AT120E cartridge. One question - could you see yourself buying something for $400 like the entry level Dynavector? (10x5 or something) Or, is the AT120E so satisfying that you'll never do it?
Hugh
I'll second that one about Duct seal from Moray. Works very well. Rona and HomeDepot sell different brands. After a decade, one of them dries out quicker, but I can't recall which is which. I can look if your curious.
Colin,
I found some of those threads on power amps. Interesting stuff.
I think I'm about to order an AT120E cartridge. One question - could you see yourself buying something for $400 like the entry level Dynavector? (10x5 or something) Or, is the AT120E so satisfying that you'll never do it?
Hugh
Ultimately if we are really concerned about any potential ringing the tubes need to be supported to the plinth on each side, up until this is done all that will happen is the q factor will be moved around. Though the lower frequency is better since it less excited by playback due to the nature of the RIAA preemphasis.
Colin
Colin
Hi Colin, and others,
Regarding both sides to plinth, I reached that conclusion about a week ago but continued on with my efforts because of seeing that just grabbing hold of the tube with my fleshy little fingers was most satisfactory in killing the ringing, completely, as far as I could tell. As it stands now I believe I have gotten the problem reduced to an acceptable (to me) level. Tried the oil/sand mix and it is marginally better than dry sand. Filling the tubes with oil only is affecting the sound, reducing the high frequency response and making it sound duller. Been listening to records this afternoon and evening. It is snowing again. Still has the oil/sand filler and that seems to be quite good. Suppose I could sit there holding the free end of the tube(s) for every listening session. The 2 tube rig is tracking beautifully.
As to the Mortite and Duct seal, I think we can add my current favorite, plumbers putty. It does the same and doesn't dry out when sealed up. Also becomes a lot softer in your hands so will pack into the small diameter tubing much easier. The others are very stiff and hard to work, iirc. Maybe I'll give the putty a try just to see how it performs.
BillG
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Bill, Moray, Colin,
I just tried a quick one. Suspended the glass tube from a string and flicked it with my finger. Rings for a couple of seconds. Then I shoved one end into the maple block and flicked it again. Can't hear any sustained ringing. The block snuffs it out nicely. So, I'm thinking Duct seal or putty may be overkill like the oil.
Also tried various papers rolled up in the tube. One with wax on one side (for laying hardwood) seemed promising. None of this was while spinning LPs - later for that.
I will definitely get around to "both sides to the plinth" too.
Thanks
Hugh
I just tried a quick one. Suspended the glass tube from a string and flicked it with my finger. Rings for a couple of seconds. Then I shoved one end into the maple block and flicked it again. Can't hear any sustained ringing. The block snuffs it out nicely. So, I'm thinking Duct seal or putty may be overkill like the oil.
Also tried various papers rolled up in the tube. One with wax on one side (for laying hardwood) seemed promising. None of this was while spinning LPs - later for that.
I will definitely get around to "both sides to the plinth" too.
Thanks
Hugh
And voila, two tube, two bearing working and non falling off arm with a dust cover, only arm lift left to go, PDR, thanks for the inspiration, this is what its all about . Seems all in all I needed to do some more work with the two tube design I tried out a couple moons back, thanks for proving it can work and needed further investigation.
Colin
. Seems all in all I needed to do some more work with the two tube design I tried out a couple moons back, thanks for proving it can work and needed further investigation.Colin
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