Are Koetsus worth it?
- Thread starter Tim Jones
- Start date
Robert
Tapehead
A better prospect would be one of the much cheaper Grado's (even the Prestige) and sending it off to a top restore like VDH to have a decent stylus fitted.
Grado styli range from dreadful to barely adequate, i.e., massy shank mounted blunt ellipticals to nude blunt ellipticals. The 'twin tip' extended profile nude styli and 'specials' of old are long gone. Spunking £3k on a modern Grado is basically a £70 Prestige Black in a pointless wooden case, perhaps with a few windings taken off the generator as an option.
They also do the same trick as AT and Ortofon, which is revamp their older models into different body shapes with little technical change. For example, I have an old F!+ high output Grado with line contact stylus, and a similar looking Z1+ which is a low output version. These mirror the situation which exists today with the wood body cartridges.
The very high end in MC cartridges is a complete rip off.
Mike Reed
pfm Member
Why, Robert, and above which v.f.m. line is 'high end'?
Do you have any examples?
Mike Reed
pfm Member
Now this is new to me; not adding a bit of weight to the head-shell so much, but how do you calibrate? Is the weight of the 5p piece/blutack/whatever simply added to what eff. mass you think your arm is (I don't know mine exactly).?
If you run out of counterweight, can you simply add weight to that end too, without upsetting the design parameters of the arm and bearing(s)?
Shuggie
Trade: Ammonite Audio
Maybe that is for a different thread, but it's a matter of total inertia, so a function of mass and its distance from the pivot, where the effective mass represents the combined masses of the arm and its counterweight, as though they exist only at the stated effective length - imagine the armtube and counterweight stubs as being totally mass-free, with a weight attached at each end. Mathematics are involved and someone on Vinyl Engine once broke it down into simple chunks, but I can't find it for now.
Anyway, if you place a small additional mass at the very end of the tonearm, it pretty much is a matter of just adding x grammes to the assumed effective mass, because that additional mass is placed at the point where the arm's effective mass is theoretically concentrated. Move the additional weight to a different point along the arm tube and mathematics are required, but that's a good way of achieving variable effective mass, as Funk Firm and, long before them, Mayware have done.
Anyway, if you place a small additional mass at the very end of the tonearm, it pretty much is a matter of just adding x grammes to the assumed effective mass, because that additional mass is placed at the point where the arm's effective mass is theoretically concentrated. Move the additional weight to a different point along the arm tube and mathematics are required, but that's a good way of achieving variable effective mass, as Funk Firm and, long before them, Mayware have done.
Elephantears
Trunkated Aesthete
I'm not going to paste in Robert's post to reply because I think it needs deleting. Some completely unresearched comments on the factual level, but equally obvious that it's based on no listening at all. How anyone can post this kind of comment without listening, based on a priori/prejudice surprises me, but to do so without any fact checking about stylus profile etc, is verging on the libellous.
The higher level Grado carts are Moving Iron, not MC, in case Robert's post mislead anyone on that score. The low output versions have qualities that aren't sharted by any comparably priced MCs that I've heard. The Statement Reference is the pick of the more 'affordable' versions. For a context relevant to the OP, I compared it directly to a Benz Wood SL and foucn it had greater texture, body and dynamic. It had less refinement in the high frequencies that the Benz but greater overall naturalism. I say this as a fan of the Benz. All reports suggest that the flagship Grado, 'The Statement', redresses this slight limitation of the Statement Reference, giving significant;y greater refinement at the extreme ends of the frequency spectrum. I'd love to do a comparison of the Statement vs an equivalent Miyajima.
The higher level Grado carts are Moving Iron, not MC, in case Robert's post mislead anyone on that score. The low output versions have qualities that aren't sharted by any comparably priced MCs that I've heard. The Statement Reference is the pick of the more 'affordable' versions. For a context relevant to the OP, I compared it directly to a Benz Wood SL and foucn it had greater texture, body and dynamic. It had less refinement in the high frequencies that the Benz but greater overall naturalism. I say this as a fan of the Benz. All reports suggest that the flagship Grado, 'The Statement', redresses this slight limitation of the Statement Reference, giving significant;y greater refinement at the extreme ends of the frequency spectrum. I'd love to do a comparison of the Statement vs an equivalent Miyajima.
Great post, Ee. I had a Grado Reference Reference1 for quite a few years - ie. a HO Grado - and my other cart was a Benz LP.
I found similar comparisons between my two carts. But I slightly preferred the Benz LP. Subsequently, I was able to score a very rare Stanton - the 'WOS CS100', their top cart - and so sold my Grado RR1. The WOS CS100 kills the Grado ... but is extremely hard to get hold of.
Andy
PS: I think Robert must've got confused that Grados are LOMC ... because of their 'Statement' range - which is only 0.5mV output.
Tony L
Administrator
In fairness I don't think Rob for a second implied it wasn't a moving iron cart, his criticism is of the stylus tip design and mounting. He is a firm believer that tip profile is a key to cart sound & tracking. I don't know enough about Grado's range to comment specifically (I don't know anything aside from I had a F1+ back in the early '80s and really liked it), but on an expensive MM type cart one would certainly expect a nude-mounted diamond with one of the better tip profiles (micro-line, Shibata, Geiger or whatever). That is certainly what one gets from Ortofon, Nagaoka, Audio Technica etc. By saying that I'd love to try a Grado again some time, though I have a feeling some may hum on big motor high-torque idler decks like mine.
Paul R
pfm Member
I wrote this up in a little detail somewhere sometime.
But in short 'effective mass' means the arm has equivalent inertia to the 'em' on the end of a weightless wand of the arm length. Effective mass numbers cannot be compared between arms of different lengths without compensating*.
The contributions of each infinitesimally small piece of the arm add up as the individual mass times the square of the distance to the pivot. There are well known equations for beams (such as the arm tube) and it's safe enough to treat counter-weights, headshells etc as point masses.
So if your arm has an em of 20g and you add 10g at the headshell the new effective mass is 20g + 10g + a bit because you moved the counterweight back. Because the counterweight is very much closer than the added mass, and the numbers go up with square of distance, and because nothing is precise, I think you can probably ignore that.
Didn't explain that well, there must be a page with pictures somewhere.
Paul
*A 9 inch arm with an em of 30g has a moment of inertia of 30*229*229 gmm2, so a 12 inch arm presenting the same inertia to a cart would need to satisfy em*305*305=30*229*229 which comes out at 17g. Which is why 12" arms aren't so universally compatible as 9".
Mike Reed
pfm Member
Thanks, Paul. The thing I understood was the '20g + 10g =30g more or less' (always loved equations ). Then you spoil it by implying that 12" arms might be a case apart. I only have, and would only have, 12" arms.
Pretty easy experiment to do, though, once I get my Urushi back in service. Not sure the Transfig. would benefit from extra mass, as I'm not up with compliance figures.
Wouldn't the type of bearing have a bearing (!) on adding mass?
). Then you spoil it by implying that 12" arms might be a case apart. I only have, and would only have, 12" arms.Pretty easy experiment to do, though, once I get my Urushi back in service. Not sure the Transfig. would benefit from extra mass, as I'm not up with compliance figures.
Wouldn't the type of bearing have a bearing (!) on adding mass?
Paul R
pfm Member
12" arms aren't a case apart, it's just that the numbers change.
So if you believe the cart needs the equivalent of 30g in a 9" arm, that's 17g in a 12". So, an SME V 12 has an em of 12g, you'd add 5g at the headshell. An SME V is 10g, so you'd add 20g. In this case the 12" arm would seem a more elegant solution.
I don't the bearing type is important, but some arms have displaced horizontal/vertical bearings, and so have slightly different effective masses in each plane. Which I guess spreads the resonances and may be a good thing. There's that 70s style Dynavector that takes this to an extreme I think.
Paul
So if you believe the cart needs the equivalent of 30g in a 9" arm, that's 17g in a 12". So, an SME V 12 has an em of 12g, you'd add 5g at the headshell. An SME V is 10g, so you'd add 20g. In this case the 12" arm would seem a more elegant solution.
I don't the bearing type is important, but some arms have displaced horizontal/vertical bearings, and so have slightly different effective masses in each plane. Which I guess spreads the resonances and may be a good thing. There's that 70s style Dynavector that takes this to an extreme I think.
Paul
Tony L
Administrator
The heavy bits of an arm are the headshell/cart at one end and counterweight at the other. The stuff in the middle is hardly anything. This is why mass calculation is pretty complex as the only figures that really matter are the combined mass of the arm/cart/headshell/mounting bolts and the compliance of the cartridge stylus assembly. Really you need to know them all. It is also why 12" arms behave differently as you are pushing the really heavy bit further away which takes more weight to balance it out.
Here is a neat little graph:
Mass is the combined arm/cart/bolts, cu the cart compliance. You want it to be in the blue zone.
PS By saying that things will often still work ok slightly outside, e.g. I'm currently running an Ortofon 540/II in a non-Improved 3009 and that works out at 12g (arm mass) +6g cart weight +screws (very short ones so I'll not count them), so an effective mass of just over 18g and a cart compliance of 30cu (which is very high). That puts the resonance a bit too low at about 7-8Hz which is possibly a bit close to record warps, though it seems to track superbly. I suspect I'd have trouble if I had a floating subchassis deck though (it is a Thorens TD-124).
Here is a neat little graph:
Mass is the combined arm/cart/bolts, cu the cart compliance. You want it to be in the blue zone.
PS By saying that things will often still work ok slightly outside, e.g. I'm currently running an Ortofon 540/II in a non-Improved 3009 and that works out at 12g (arm mass) +6g cart weight +screws (very short ones so I'll not count them), so an effective mass of just over 18g and a cart compliance of 30cu (which is very high). That puts the resonance a bit too low at about 7-8Hz which is possibly a bit close to record warps, though it seems to track superbly. I suspect I'd have trouble if I had a floating subchassis deck though (it is a Thorens TD-124).
Paul R
pfm Member
It should be possible to calculate this, but it's likely the reply box is too small.
The theoretical resonant frequency is given by,
f=1/(2Pi)*sqrt(k/I)
where 'k' is the rotational spring constant in Nm/rad and I is the moment of inertia in kgm2.
So I think that gives, for a resonant frequency of 10Hz,
k=20Pi*20Pi*I
30g em gives an I of 0.003*0.228*0.228 kgm2.
k therefore would ideally be 0.62. Just need to convert that to 'CU' to see whether sanity is checked.
Paul
The theoretical resonant frequency is given by,
f=1/(2Pi)*sqrt(k/I)
where 'k' is the rotational spring constant in Nm/rad and I is the moment of inertia in kgm2.
So I think that gives, for a resonant frequency of 10Hz,
k=20Pi*20Pi*I
30g em gives an I of 0.003*0.228*0.228 kgm2.
k therefore would ideally be 0.62. Just need to convert that to 'CU' to see whether sanity is checked.
Paul
Paul R
pfm Member
And I'll need a piece of paper to figure that out. CU are equivalent to mm/N, just need to convert that to torque/radian at our chosen arm length and etc etc.
(I should think a Koetsu is worth trying. I'd be tempted to source a second hand item and have it refurbished, even non-factory will give a strong sense of the flavour)
Paul
(I should think a Koetsu is worth trying. I'd be tempted to source a second hand item and have it refurbished, even non-factory will give a strong sense of the flavour)
Paul
These different materials have different stiffnesses. Most metals have the same specific stiffness, ie modulus/weight, meaning that steel, aluminium, magnesium and titanium parts of the same weight will have the same stiffness, in principle, though the geometry has a big effect too, in bending, so a steel rod will be less stiff in bending than a titanium rod which will be less stiff than an aluminium rod which will be less stiff than a magnesium rod if they all weigh the same. Beryllium and Boron are exceptions, having considerably higher specific stiffness than common metals. A Boron rod is much stiffer than the other metals. Diamond and Sapphire are stiffer again. Composite materials like carbon fibre reinforced matrices and bamboo (God's composite
) are actually much less stiff than metals.But on top of this the geometry makes a huge difference in bending. A tapered tube is inherently stiffer by weight than a straight tube, which is stiffer than a rod, which complicates things somewhat.
B&O used a Sapphire tube in their MMC1 cartridge, which was a bargain IMHO.
It is almost certain that the stiffer the cantilever the more accurate the transduction, but that is not the only thing effecting the sound, of course, and there is plenty of evidence that different people prefer different sounds too.
I would consider a cartridge with a bamboo cantilever more of a fashion item than a bit of sound (in both senses of the word) engineering.
It is additionally complicated by the fact that in many, if not all, cartridges the principle suspension is a polymer, not a spring, so it will have quite a bit of internal damping and the stiffness will vary with temperature and age.
The static compliance will differ from the dynamic compliance and the way it is measured will effect the number too.
I used to design seismic vibration transducers for my own use many years ago but didn't have to compromise nearly as much as is forced on cartridge designers, variability in the "spring" is a non-trivial source of inconsistency and inaccuracy.
Basically all output from such a transducer below ~2x the natural frequency of the mass on the spring is amplified by the resonance. This is made all the worse if the RIAA stage hasn't got the later (1976) bass rolloff built in since the error is boosted by 20db as well if it doesn't!
These different materials have different stiffnesses. Most metals have the same specific stiffness, ie modulus/weight, meaning that steel, aluminium, magnesium and titanium parts of the same weight will have the same stiffness, in principle, though the geometry has a big effect too, in bending, so a steel rod will be less stiff in bending than a titanium rod which will be less stiff than an aluminium rod which will be less stiff than a magnesium rod if they all weigh the same. Beryllium and Boron are exceptions, having considerably higher specific stiffness than common metals. A Boron rod is much stiffer than the other metals. Diamond and Sapphire are stiffer again. Composite materials like carbon fibre reinforced matrices and bamboo (God's composite
But on top of this the geometry makes a huge difference in bending. A tapered tube is inherently stiffer by weight than a straight tube, which is stiffer than a rod, which complicates things somewhat.
B&O used a Sapphire tube in their MMC1 cartridge, which was a bargain IMHO.
It is almost certain that the stiffer the cantilever the more accurate the transduction, but that is not the only thing effecting the sound, of course, and there is plenty of evidence that different people prefer different sounds too.
I would consider a cartridge with a bamboo cantilever more of a fashion item than a bit of sound (in both senses of the word) engineering.
A very good explanation, Frank. Thank you.
I do wonder though, if some of the colouration (however derived) that all cartridges display is part of their charm. Not hifi in the strictest sense, but pleasing to the ear, nonetheless.