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substantially better at 3g than the 2g I was using - dunno why but thought I read it somewhere this morning when trying to find what weight to use
might still need a little VTA and alignment tweaking (not great eyesight and clumsy to boot)
doesnt appear to need another (or extra) weight as the weight is middle ish of the travel available - am I mis uderstanding the need for weight (ie need it if you cant get it to balance at 3g)
thanks for help thus far - getting there now
Darren
Hi Darren,
I just remembered that it's the N21D stylus you've got so the max is 2.5g - I'd therefore reduce VTF to 2.5g.
No you need to add extra weight to the headshell only to increase the arm's effective mass, as the M3D is designed to operate in high-mass arms - much more so than your Alphason is as standard; that's why I mentioned Blu-Tacking coins onto the headshell :)
When you do this things should improve quite dramatically. Don't worry too much about balancing the arm - as long as you can measure 2.5g VTF using your stylus pressure gauge with the extra weight on the headshell it will be fine.
My own N21D stylus has just arrived from the States so I'll be having a play myself later :smoking:
Marco.
I'm finding the MC30 Super too brightly lit for even my tastes and I remembered I had what I thought was a knackered AT OC9 in the loft. I brought it down, cleaned the stylus only to find it's still ok. I mounted it up in a spare headslide, noting that the fixing isn't straight AT but either a "Deccapod" kind of arrangement (two copper coloured recessed Allen bolts each side holding the golden cartridge body in place) or it's possibly the Stilton modified version.
I've had the above in the loft for getting on for twenty years and wasn't expecting it to sound any good, as it was very sick when traded in, but after about 10 seconds to sort itself out, it sounds great with very good tracking, only missing the way a good fine-line or micro-ridge tip seems to trace unworn parts of the groove..............
I'm really worried that I'll find the M3d/N21 a bit rough and coloured with too much bass energy, which is something I really don't need..
Please keep this thread open. I'll await Marco's findings on which stylus to get and then I'll jump in.
Guys
prolly being a bit thick here but if you add mass to the headshell (penny and bluetack) you just have to add mass to the other end to balance it off at 2.5 grams - so if it balances at 2.5 with no pennies or blue tack then why is it better to add mass to both sides and have it looking like a dogs dinner?
confused from stoke - unless its about having a bit of extra pressure on the bearings but whats that got to do with the cart
is there something to read on the interweb re this stuff - learnning new tricks is giving me a headache
having reviewed my set up technique I think I have it all right except perhaps the overhang - if I am out on this by a mill or two what sound difference could I expect (distortion - now mild not pronounced so getting there!)
apologies for all the questions - having fun learning
rgds
darren
Darren,
Adding mass to the headshell in terms of added weight has got nothing to do with balancing the arm in reference to VTF - it's about cartridge compliance, which is a discussion for another thread.
Your M3D needs added headshell mass in your (lightweight) arm in order to perform as intended, so add the coins as I suggested, as long as after doing so you can achieve VTF of 2.5g.
If it works, and the sound is improved, you can get a nice brass or metal plate made to the same 'mass' as the coins and Blu-Tac, which will simply insert between your M3D and the headshell relatively invisibly :)
Now just go and DO it! Yer uncle Marco knows best :lolsign:
;)
Marco.
Marco
already did it just wanted to know why I am doing it - looks like blu tack arm but its balanced and playing away - not shure if its made much difference so I am now going to try resetting all the bits I did earlier to make sure I havent buggered something up
its almost good now but it doesnt sound great - will leaving it running help - I am playing an old ZZ top disc now thats so warped it will be a good excercise work out for the stylus to losen things up a bit
point me in the direction of an article on compliance would ya uncle M
Rgds
darren
ok found this -
Tonearm/Cartridge Capability
For best performance, the tonearm and cartridge must be matched. All cartridges will not work with all tonearms, and vice versa. To insure a proper match, one must be aware of the mechanical specifications of both the arm and phono cartridge. To see how these characteristics interact and determine compatibility, we must first understand the dynamics of the relationship.
Any cartridge/tonearm combination will exhibit resonance at a specific frequency (or frequencies). This resonance is due to the interaction of the cartridge (acting as a spring), and the weight of the arm (acting as a mass). The "springiness" of the phono cartridge is described as compliance, the weight of the arm is specified in mass. As an example, a heavy weight on a light spring would obviously over-flex the spring, conversely, a light weight on a strong spring would not allow sufficient flexion.
At resonance, the arm/cartridge combination produces a dramatic rise in output. An increase of 3 to 6dB or more is common. This tremendous boost can cause severe problems if it occurs in the region of recorded music (above 2OHz), or in the area where record warps and rumble are problematic (below 5Hz). A cartridge/arm whose resonance occurs in the region above 2OHz can be influenced by music on the record. At this frequency a significant jump in output (resulting in a "bloated" or "tubby" sound) will be experienced. In extreme cases, the stylus may actually jump out of the groove. Similarly, a cartridge/arm combination that exhibits a resonance below the desired range will exaggerate the effects of record warps, or rumble produced by the turntable.
The goal in matching a specific cartridge and arm is to achieve a resonance in the 10 to 14Hz range. Some feel that limiting this range even further, to 9 to 11hZ, is best.
I've seen the following formula for calculating the resonant frequency of an arm/cartridge:
Resonant Frequency = 1000/[6.28*square root (M*C)]. Where M is the mass of the arm and cartridge and C is the compliance of the cartridge. As an example, if we had an arm/cartridge with a combined mass of 14g, and a cartridge with a compliance of 20, the resonant frequency would be 9.535.
This simple equation doesn't take into account all factors, including tonearm damping and, internal cartridge damping, but it will give you general idea of compatibility.
A decade ago, high-compliance cartridges were the rage and these needed to mate with very low mass tonearms. However, today’s heavier, lower-compliance phono cartridges (especially moving coils) have required tonearm designers/manufacturers to reorient themselves in the direction of medium to high-mass arms. Further, some of the currently available MC cartridges put back a tremendous amount of energy into the arm. This reflected energy takes the form of standing waves, which travel up and down the length of the tonearm, potentially creating mis-tracking problems and/or frequency dependent cancellation. A well designed tonearm will dissipate this energy, rather than reflecting it back to the cartridge. The ability of the arm to accomplish this will be dependent upon bearing design, internal damping and rigidity.
In a situation where a higher compliance cartridge is employed in a medium to high mass tonearm, the ill-effects of the match can be mitigated to some degree if the tonearm offers fluid damping. Here, a small paddle connected to the arm rests in a reservoir filled with viscous silicone fluid. This design feature restricts small, rapid motions of the arm (like the small undulations that would occur in a high-compliance cartridge), while providing unrestricted progress to the arm as it slowly traces across the record. This system also may improve the sound of some phono cartridges that offer little internal damping of their own.
The only way to accurately measure system resonance is with a calibrated low frequency test record and a chart recorder, or other sophisticated test equipment. Since most of us do not possess this capability, it is wise to do some preliminary homework in assessing the compatibility of any potential arm/cartridge combination. There are a few general "rules of thumb" that we need to consider:
* A tonearm whose effective mass is rated at 10 grams or below is considered low mass (e.g. early SME’s, Grace 747 etc.). A tonearm whose effective mass is rated between 11 and 25 grams is considered moderate mass (e.g. SME 309, IV, IV-Vi, V, Triplanar, Graham). Arms above 25 grams of mass are high mass in nature (Eminent Technology, Dynavector).
* A phono cartridge whose compliance is rated at 12 x l0ˉ6 or below, is considered low compliance. A cartridge whose compliance is rated between 13 x l0ˉ6 and 25 x l0ˉ6 is considered high to very high. Note: Another way of expressing compliance is um/mN. Here a rating of 5 to 10 is considered very low, 10 to 20 is moderate and above 35 is very high.
* Low mass arms mate well with both moderately high and very high compliance phono cartridges.
* Moderate mass tonearms are good companions for moderate to low compliance cartridges.
* If a low compliance cartridge is used with a low mass tonearm, undesirable resonances can occur in the audible range. Mistracking may also be a problem.
* When a high compliance cartridge is mated with a moderate mass tonearm, resonances in the infrasonic range may occur in addition to some unwanted high frequency damping.
It may not be possible in every case to accurately determine whether a particular cartridge is suited to a given tonearm by a simple glance at the specifications. This is especially true in border-line situations. However, poor combinations can be easily identified and avoided.
Several variables can influence our ability to accurately predict a match using the manufacturers supplied specifications. Some of these are: 1) The manufacturers specifications themselves can vary in accuracy due to differences in measurement techniques. 2) Sample to sample variation of the cartridge. 3) Differing amounts of internal damping of the cartridge or tonearm and 4) the age of the cartridge. The situation is further complicated by the fact that we should calculate both vertical and horizontal resonance points.
Happily, most of the popular, modem-day moving coil (and many moving magnet) cartridges and the current crop of medium mass tonearms represent a fairly good match. Exceptions do exist however, and we should be aware of the sonic pitfalls. An improperly matched cartridge and tonearm will not only sound poorly, it may even cause irreparable damage to records and stylus. So, it is well worth the effort in preliminary comparisons to determine the compatibility of the proposed cartridge and tonearm
now per vinyl engine the alphason is:
Description
Over seven years professional design and development, including computer aided structural and vibrational analysis, together with top quality materials and precision construction, goes into making this the worlds best sounding tonearm.
Not only have basic parameters of tracking error, bearing friction and effective mass been catered for, but also such advanced scientific details as rigidity, resonances, energy paths and structural damping have been analytically optimised.
The Alphason HR100S is a most unusual arm. An ultra-strong, one-piece titanium casting forms the arm-tube and head shell; tool-grade steel is used for the gimbal-bearing housing and ultra-tough ceramic for the bearings themselves.
Specifications
Effective length: 229mm
Mounting distance: 211mm
Overhang: 18mm
Effective mass: 11g
and the shure is a low compliance cart
so should it be ok given above it said - * Moderate mass tonearms are good companions for moderate to low compliance cartridges.
11g is the lower end of moderate so I guess the pennies are adding to this to make it firmly moderate - is this right?
cheers
Darren
Yes the pennies are adding to the effective mass of your arm. Your next assignment is to research 'effective mass'. You need to understand how it influences the performance of the cartridge in terms of resonance.
Fun this, isn't it - who needs to play music? :lol: ;)
Marco.
playing music as I learn - tah mahal
googling effective mass next once picked up daughter number on from local gig
cheers
Darren
LOL - it's all go!
Marco.