Perhaps this will be of interest...
I just completed building a custom base Teres turntable and a DIY linear tracking, air-bearing tonearm. The tonearm design uses ideas from the ETII and Morch arms. You can check it out at:
http://mywebpages.comcast.net/paulebert/
The audience for the web site was fellow Teres builders, so it may not be entirely comprehensible. Feel free to ask questions.
I highly recommend the Teres to anyone wanting to build a turntable.
Paul Ebert
I just completed building a custom base Teres turntable and a DIY linear tracking, air-bearing tonearm. The tonearm design uses ideas from the ETII and Morch arms. You can check it out at:
http://mywebpages.comcast.net/paulebert/
The audience for the web site was fellow Teres builders, so it may not be entirely comprehensible. Feel free to ask questions.
I highly recommend the Teres to anyone wanting to build a turntable.
Paul Ebert
Thanks for the kind words, Guys.
My old 'table is a Linn LP12 with an Akito (nothing near as nice as a Platine Verdier). I also own a UP-4. A while back the Akito broke, so the UP-4 was purchased to either go on the Teres if the DIY arm didn't work out or to be sold with the LP12. Once I have the UP-4 mounted on the Linn, I will probably compare it to the Teres, but it will probably not be a fair comparison. The Linn has a way past it's prime 10X4 II on it and the Teres a Grado Black. I plan to purchase a better cartridge for the Teres, but that will put the Linn at a disadvantage due to the age of the Dynavector. I don't feel like buying an additional cartridge just to make a valid comparison.
The Teres currently does not have any suspension, nor has it needed one. At least not that I've noticed. The old entertainment unit it is in is rigidly attached to the studs in the wall behind it and footfalls, etc. haven't been an issue with either the Teres or the Linn. If I do give it some sort of suspension, I would like to experiment with rare earth magnet levitation. But that's a few projects away, at least.
Paul
My old 'table is a Linn LP12 with an Akito (nothing near as nice as a Platine Verdier). I also own a UP-4. A while back the Akito broke, so the UP-4 was purchased to either go on the Teres if the DIY arm didn't work out or to be sold with the LP12. Once I have the UP-4 mounted on the Linn, I will probably compare it to the Teres, but it will probably not be a fair comparison. The Linn has a way past it's prime 10X4 II on it and the Teres a Grado Black. I plan to purchase a better cartridge for the Teres, but that will put the Linn at a disadvantage due to the age of the Dynavector. I don't feel like buying an additional cartridge just to make a valid comparison.
The Teres currently does not have any suspension, nor has it needed one. At least not that I've noticed. The old entertainment unit it is in is rigidly attached to the studs in the wall behind it and footfalls, etc. haven't been an issue with either the Teres or the Linn. If I do give it some sort of suspension, I would like to experiment with rare earth magnet levitation. But that's a few projects away, at least.
Paul
Very nice job, Paul- my congrats!
Some questions, with you permission.
1. What kind of air bushing used - something ready made? Is it high or low pressure bearing? What pump is used?
2. As you noticed, the lateral mass is somehow high, because of solid rod used for slider - you may drill it from either side to max depth (?). From my experience (Ladegaard tonearm on earlier thread) it is essential to make the slider as light as posiible, because even the lightest one has much more lateral mass than any pivoted tonearm. My last version arm made of balsa wood still need to loose several grams - I can hear some distortions playing LP's with heavy excenticity. Conty (Basis Vector arm author) claims in his article, that all linear trackers have excessive lateral mass. Anyhow, there should be some kind of proportion between lateral and vertial effective mass.
3. Ideally, the arm pivot axle should be placed on the same plane as LP surface. Otherwise, overhang will vary slightly when the needle goes up and down over the surface imperfections. VTA is also more influenced by this for shorter arm. Have you noticed any sound unstability when playing not perfectly flat record? May be it is just theoretical issue, I don't know.
Regard,
Michael
Some questions, with you permission.
1. What kind of air bushing used - something ready made? Is it high or low pressure bearing? What pump is used?
2. As you noticed, the lateral mass is somehow high, because of solid rod used for slider - you may drill it from either side to max depth (?). From my experience (Ladegaard tonearm on earlier thread) it is essential to make the slider as light as posiible, because even the lightest one has much more lateral mass than any pivoted tonearm. My last version arm made of balsa wood still need to loose several grams - I can hear some distortions playing LP's with heavy excenticity. Conty (Basis Vector arm author) claims in his article, that all linear trackers have excessive lateral mass. Anyhow, there should be some kind of proportion between lateral and vertial effective mass.
3. Ideally, the arm pivot axle should be placed on the same plane as LP surface. Otherwise, overhang will vary slightly when the needle goes up and down over the surface imperfections. VTA is also more influenced by this for shorter arm. Have you noticed any sound unstability when playing not perfectly flat record? May be it is just theoretical issue, I don't know.
Regard,
Michael
Let me address Michael's questions, first.
1. The air bushing is from New Way Bearings (www.newwaybearings.com). It is part #S301201 and the pillow block for it is part #S8012P01. They aren't cheap. The pair is about $240. It will operate between 40 and 80 psi, with 60 being recommended (high pressure for a tone arm). I managed to find a relatively quiet oil-less air compressor. It is a Thomas 607FA22 compressor. Even that is too loud (57 dB). It resides in the basement.
2. Yes, the lateral mass is quite high. But, apparently, it's a matter of controversy whether that is good or bad. As you probably know, Poul Ladegaard considered it beneficial. I've heard of ETII owners filling their shafts with sand to increase the horizontal mass, thereby improving dynamics. Of course, it must be compatible with your cartridge. Unfortunately, the compliance spec supplied by cartridge manufacturers does not differentiate between vertical and horizontal compliance. The Grado Black I'm using as a test cartridge works OK and it is specified at 20x10-6 cm/dyne. If there is a mismatch, it will appear at lead-in and lead-out grooves and with eccentricity, as you mention. I will probably reduce the horizontal mass as I am able.
3. Yes (again), the axis should be lower. On my next revision, I may lower it, though (again), it hasn't been a problem. I haven't played any really warped records. I went with the short arm as a way of reducing effective mass.
As to pictures or drawings, I'll try to post more pictures, but, for some reason, my digital camera is not working well. I'm hesitant to create drawings as this is really a prototype. It works well, but I'd do things quite a bit different (especially the vta adjustment). My recommendation for anyone wanting to make a linear tracker would probably be to build a Ladegaard arm. Being lower pressure, it's much easier to obtain a suitable pump and it has no costly bushing. Between the air-bushing and the pump, my arm ended up costing about the same as a used ETII. Of course, I have all of the DIY benefits. The high pressure is certainly a sonic benefit as well. I think that using the air bearing for both axis is also a benefit over the Ladegaard. But, the Ladegaard gives an incredible amount of value.
My arm was really easy to make. Besides the bushing, the only other specialized part was the slider shaft. That was part #1031K12 from McMaster-Carr (www.mcmaster.com). I probably spent about 40 hours making it, including the cable. The cable took about 12 hours. The only critical part was making sure that the arm tube was precisely 90 degrees from the slider shaft.
Feel free to ask more questions.
Paul
1. The air bushing is from New Way Bearings (www.newwaybearings.com). It is part #S301201 and the pillow block for it is part #S8012P01. They aren't cheap. The pair is about $240. It will operate between 40 and 80 psi, with 60 being recommended (high pressure for a tone arm). I managed to find a relatively quiet oil-less air compressor. It is a Thomas 607FA22 compressor. Even that is too loud (57 dB). It resides in the basement.
2. Yes, the lateral mass is quite high. But, apparently, it's a matter of controversy whether that is good or bad. As you probably know, Poul Ladegaard considered it beneficial. I've heard of ETII owners filling their shafts with sand to increase the horizontal mass, thereby improving dynamics. Of course, it must be compatible with your cartridge. Unfortunately, the compliance spec supplied by cartridge manufacturers does not differentiate between vertical and horizontal compliance. The Grado Black I'm using as a test cartridge works OK and it is specified at 20x10-6 cm/dyne. If there is a mismatch, it will appear at lead-in and lead-out grooves and with eccentricity, as you mention. I will probably reduce the horizontal mass as I am able.
3. Yes (again), the axis should be lower. On my next revision, I may lower it, though (again), it hasn't been a problem. I haven't played any really warped records. I went with the short arm as a way of reducing effective mass.
As to pictures or drawings, I'll try to post more pictures, but, for some reason, my digital camera is not working well. I'm hesitant to create drawings as this is really a prototype. It works well, but I'd do things quite a bit different (especially the vta adjustment). My recommendation for anyone wanting to make a linear tracker would probably be to build a Ladegaard arm. Being lower pressure, it's much easier to obtain a suitable pump and it has no costly bushing. Between the air-bushing and the pump, my arm ended up costing about the same as a used ETII. Of course, I have all of the DIY benefits. The high pressure is certainly a sonic benefit as well. I think that using the air bearing for both axis is also a benefit over the Ladegaard. But, the Ladegaard gives an incredible amount of value.
My arm was really easy to make. Besides the bushing, the only other specialized part was the slider shaft. That was part #1031K12 from McMaster-Carr (www.mcmaster.com). I probably spent about 40 hours making it, including the cable. The cable took about 12 hours. The only critical part was making sure that the arm tube was precisely 90 degrees from the slider shaft.
Feel free to ask more questions.
Paul
Paul Ebert said:
Did you make any comparison tests? I just curious, does the high pressure tonearm have real sonic benefit? Teoretically yes, because of higher bearing stiffness. But one can make low pressure slider longer and thereby increase the torsion and lateral reaction moment - actually the same thing the high stiffness does.
BTW, one of the most expensive tonearms (Airtangent) has low pressure design.
Michael
Hi,
I once tried to put a valve on the air-hose for my air-bearing-arm,
so I could adjust the air pressure, not because I wanted to adjust
for best sound, but because the arm was so noisy.
I could clearly hear the hiss from the air pressure at the listening position.
What I found was that the sound was best with high pressure.
I could turn the pressure down and the sound got worse, when
the pressure was so I couldn't hear it from the listening chair, the
sound got really bad.
The solution was to go back to high air pressure ,
and move the record player and preamp to the next room,
which improved the sound even more.
I once tried to put a valve on the air-hose for my air-bearing-arm,
so I could adjust the air pressure, not because I wanted to adjust
for best sound, but because the arm was so noisy.
I could clearly hear the hiss from the air pressure at the listening position.
What I found was that the sound was best with high pressure.
I could turn the pressure down and the sound got worse, when
the pressure was so I couldn't hear it from the listening chair, the
sound got really bad.
The solution was to go back to high air pressure ,
and move the record player and preamp to the next room,
which improved the sound even more.
livemusic said:
Correct, again, Michael. You bring up very good points!
The only comparison I've done is changing the pressure on my arm. There is a fairly clear increase in dynamics and clarity as I go from 30 to 60 psi on my setup. I guess I was thinking that higher pressure was certainly an improvement, keeping all other factors the same. But, perhaps even that is questionable. I wouldn't begin to compare myself with the likes of the Airtangent designer. To the contrary, I am astonished that my arm works as well as it does, given my level of expertise, which is at the novice DIYer level.
As you astutely point out, there is more than one way to achieve torsional rigidity. I would like to add another bushing at some point, but I'm not sure I could justify the price. Frankly, I'm not out to have a state of the art arm.
I do think that at some point, I'll buy an additional slider shaft or two and experiment with drilling it out. They're less than $5, so experimenting with them is cheap. OTOH, other components in my system are in such drastic need of improvement (esp. speakers), that it may be quite a while before I feel the need to improve the arm.
Paul
Da5id4Vz said:
What's a nano-webber?
I bought the tape at a local consignment store. It was 25 cents for a whole reel of it. The box was marked "Nixon vs. Kennedy Debate". I figured that it would not be of too much interest. The tape does seem to make very good belt material (No, I haven't compared
, but others have).Speaking of the tape, soon after completing the table, my wife said something to the effect of: "The only thing I don't like is the brown tape. Couldn't you get it in black?". Does anyone know if it's possible to get reel-to-reel tape in black?
Paul
slowmotion said:
That was a significant concern of mine when I first considered using the New Way bushing, given the high pressures. But, the rep assured me that, because of the porous design, it would be silent. And, it is. Even at 60 psi, I can hardly hear the air right next to it with no music playing. The way this works is that the material that makes up the bushing is a porous carbon that releases the air everywhere on its bearing surface, rather than specific holes. So there is no air rush. It really is quite impressive.
BTW, I have no affiliation with New Way other than buying one bushing
.
UNDER PRESSURE...
Hi,
Yes, I still have one of those...used to have two.
They start to sound their best at high pressure, as Slowmotion said the hiss from the escaping air made put the turntable far enough away to make it inaudible from the listening position.
I found it was mostly the bass region that benefitted most.
Cheers,
Hi,
Yes, I still have one of those...used to have two.
They start to sound their best at high pressure, as Slowmotion said the hiss from the escaping air made put the turntable far enough away to make it inaudible from the listening position.
I found it was mostly the bass region that benefitted most.
Cheers,
The nano-webber was a measure of magnetic permeability. It was one of the alignment factors used in magnetic tape to guarantee optimum saturating of the tape and interchange with other machines. There are meters for measuring it, but for my work I always adjusted a machine against a piece of purchased laboratory manufactured reference tape.
Can’t off hand remember how the webber and the oersted relate. (You roast the oesters on the webber grill?)
I recall that 456 is dark gray on the backing side and light brown on the ferrite emulsion side. The case I was referring to is in a mothball facility I help out at. Next time I'm out there I can grab some for you, but there is still a small problem. For your use, you should always have the backing side against the motor capstan and platter. The oxide side would tend to wear off potentially converting itself to a lubricant. This unfortunately will leave you with shades of brown, unless you want to try VHS tape. That, although thinner than audiotape, will be dark gray on the emulsion that you want outside.
Missing Nixon tapes at a second hand store? It could happen.
Can’t off hand remember how the webber and the oersted relate. (You roast the oesters on the webber grill?)
I recall that 456 is dark gray on the backing side and light brown on the ferrite emulsion side. The case I was referring to is in a mothball facility I help out at. Next time I'm out there I can grab some for you, but there is still a small problem. For your use, you should always have the backing side against the motor capstan and platter. The oxide side would tend to wear off potentially converting itself to a lubricant. This unfortunately will leave you with shades of brown, unless you want to try VHS tape. That, although thinner than audiotape, will be dark gray on the emulsion that you want outside.
Missing Nixon tapes at a second hand store? It could happen.
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