2. analog
  3. 1117142645

TriPlanar Tips

The manual that comes with the TriPlanar Mk VII tonearm is fairly complete, but there are a few things I’ve learned only by living with the arm. Note: I do not know which if any of these would apply to previous versions of the arm. My only experience is with the Mk VII.

1. NEVER raise the cueing lever while the arm is locked in the arm rest. This pressures the damping cylinder and could cause a silicone leak. For this reason and also for safety, whenever the arm is in the arm rest the cueing lever should be DOWN. This is backwards from most arms and takes some getting used to.

2. If your Tri-Planar doesn't cue straight down there's a quick fix, which may be included on some new arms. The problem is insufficient friction between the arm tube and the hard rubber cueing support bar. Just glue a bit of thin sandpaper to the underside of the arm tube. Make it big enough and position it so it hits the cueing support bar at all points across the arm’s arc. (Note: after doing this you will need to adjust the cueing height, see Tip #3.)

3. When adjusting cueing height (instructions are in the manual) always do so with the arm in the UP position. This adjustment is VERY touchy, since the cueing support bar is so close to the pivot. Be patient and be careful of your cartridge. (Note: after doing this you may need to adjust the anti-skate initiation point, see Tip #4.)

Chris Brady of Teres told me of a way to improve cueing even more by re-shaping the cueing support. Moving the cueing support point farther from the pivot improves its mechanical advantage and makes the cueing height and speed adjustments less touchy. This mod is easier than it sounds and requires only a length of coat hanger (!), but I don’t have pix and haven’t yet done it myself.

4. Changing the cueing height affects the point where anti-skate kicks in. (Yes, it's weird.) Once cueing height is satisfactory, adjust the short pin that sticks out of the front of the cueing frame. That pin controls where the anti-skate dogleg first engages the knot on the string.

5. The Tri-Planar comes with three counterweight donuts of differing masses. Many cartridges can be balanced using either of two. The arm usually tracks best with the heaviest donut that will work, mounted closer to the pivot. Of course this also reduces effective mass, which may or may not be sonically desirable depending on the cartridge. It also leaves more room for Tip #6.

6. For fine VTF adjustments don’t futz with the counterweight, there’s an easier way. Set the counterweight for the highest VTF you think you’ll need (ie, close to the pivot). Pick up some 1/4" I.D. O-rings from Home Depot. To reduce VTF a bit just slip an O-ring or two on the end stub. Thin O-rings reduce VTF by .01-.02g, thick ones by .04-.05g. Quick, cheap, effective. (For safety, always lock the arm down while adding or removing O-rings.)

7. When adjusting VTA, always bring the pointer to the setting you want by turning it counter-clockwise at least ¼ of a turn. This brings the arm UP to the spot you've selected, which takes up the slop in the threads. You can easily feel this happening.

Hope someone finds these useful. If you know any more, please bring ‘em on!
dougdeacon
dan_ed
2,451 posts
 
Paperw8, while you're experimenting with removing the trough, here is something for you to ponder about. The equation you cited for estimating the resonant frequency of the system formed by the arm/cart is just that. An estimate. Real measurements of a given arm/cart often give different results. This equation should be taken as nothing more than a sanity check of the particular arm/cart pairing being considered. If the numbers are close you are probably ok but nothing more. If the numbers are off you need to find another combination.

You are on the right track with this tonearm resonance issue. It is very much a result of the amount of energy a cart is allowed to impart back into the arm. This is not only a function of the compliance, but also the damping of the cartridge itself. Some cartridges are notorious for transferring relatively significant amounts of energy into the arm. At that point it becomes the problem of the arm designer to deal with these vibrations. Again, we're talking about the small (small to us, but potentially devastating to our delicate arm/cart system) amount of energy generated in the cantilever and cartridge body. I hope from this that you can see why tapping is akin to driving an amp into saturation. It really doesn't say much at all about what happens during normal playback.

I have no formal arts training either, but do have degrees in EE and CS, so maybe we can find a common line of reasoning.
paperw8
165 posts
 

You are on the right track with this tonearm resonance issue. It is very much a result of the amount of energy a cart is allowed to impart back into the arm. This is not only a function of the compliance, but also the damping of the cartridge itself. Some cartridges are notorious for transferring relatively significant amounts of energy into the arm.
I'm not understanding the distinction that you are making between "compliance" and "damping". In fact, I'm not sure that I understand how you are modeling the system. I will tell you how I conceive the system model and then you can comment on where I might be incorrect or leaving out relevant information.

The cantilever is attached to suspension within the body of the cartridge. That suspension can effectively be modeled as a spring. The total of the effective mass of the tonearm and the mass of the cartridge can be modeled as a mass that is attached to the spring. In a spring system, energy can get trapped within the spring when you excite the spring at a resonant frequency for the spring. That's what causes the spring to vibrate out of control. In the cartridge context, the excitation for the spring comes by way of the stylus. The source of the excitation is any energy source that couples through the stylus, this includes the groove of the record, vibrations from footsteps, etc.

Under normal circumstances, the kinetic energy from the excitation is passed through to the attached mass (cartridge body and tonearm). Maybe this is what you are referring to by "damping", but that occurs outside of the cantilever. So, if you want to test the ability of the tonearm to dampen vibrations, you can do that test separately from the cantilever. That was the "tap" test that I described earlier - it was a test to see how well the tonearm could dampen vibrations. As Atmasphere stated, the Triplanar is made using vibration dampening material (I don't personally know that to be the fact, but it seems reasonable to me).

In the case of a resonance in the cantilever, kinetic energy gets trapped in the cantilever suspension and the spring vibrates in an out of control fashion. At a resonance, significant amounts of kinetic energy are transferred to the tonearm. So now you have a situation where there is a lot of energy being transferred from the stylus (which is vibrating) to the cantilever and from the mass (cartridge/tonearm), which is also vibrating. So energy is being transferred into the cantilever (spring) from both ends. When the frequency of energy transfer is just right (i.e. at the resonant frequency) this creates an unstable condition called a resonance. This is the physical mechanism by which the resonance in the cartridge cantilever operates.

A resonance that originates within the tonearm would be a different mechanism. I no reason to presume that such a resonance would, per force, trigger a resonance in the cartridge cantilever, but I would expect the cartridge to pick up the energy from this resonance. If the resonance is within the audible spectrum, I would expect that you would be able to hear it.

Apparently some here believe that the Triplanar has such resonant properties. I don't know; I've told you the sum total of my testing on the matter. But for my part, I'm probably at least as interested in understanding how all this stuff works together than I am seeking the "ultimate" sonic experience. When I got my turntable system, my attitude about it was to get a system that I expected would sound pretty good (it was replacing a Technics SL-BD20D turntable that I had had for a decade). While I ended up with a turntable system that sounded pretty good to me, what I did not like about the process was the large number of unknowns. There are 5 components that work together in a turntable system: the turntable, the tonearm, the cartridge, the phono stage and the tonearm cable. There seems to be a belief that some turntables work better with certain tonearms. I could never get a good explanation as to how these determinations were made other than they were the result of trial and error. I have since gained a better understanding (through my own efforts) of the relationship between the tonearm and cartridge, and between the cartridge, tonearm cable and phono stage. I engage in discussion like this because my primary interest is understanding how stuff works and to that end, I've learned quite a bit in discussions like this. In some ways, you can learn more when you disagree with a person than when you agree.
stltrains
845 posts
 
I not only removed the trough assy from my TP. But if you haven't removed the anti skate devise also you haven't heard what superior sound a Triplaner can retrieve from a vinyl record no joke.
dan_ed
2,451 posts
 
Doug, please make a call on this. This is turning into a much deeper, and much more intelligent, discussion on this topic of arm/cart resonances. While it is relevant to the thread topic it will venture in other directions. We can discuss here, or take it to another thread.
dougdeacon OP
3,338 posts
 
Dan,

Thank you for asking, I appreciate it. You'll find the answer in my last post, dated 08/27/10. I haven't posted since as it would be fatuous to contribute to a discussion after explicitly asking that it stop.

If the next post on this thread were a new tip or a practical question/report regarding an old tip, it would serve the purposes of this thread. Anything else probably wouldn't.

It needs two to argue, but only one to stop.
More to discover