Tonearm and cartridge matching.... A black art?
OK.....
This is a very thorny issue that can cause arguments to rage on for ages.
The interesting thing is that the arguments rage on about the minutae rather than the overarching concept.
To start with, the basics have to be addressed.
First, how does the cartridge work?
There are two fundamental parts. First the coils, then the magnets. In a moving coil, as the name suggests, the coils move. In a moving magnet, the magnets move. Both have the same parts. In an mm, the magnets are fixed to the cantilever, the cantilever has the stylus on the end of it, and this traces the groove. When it does this, the magnets on the other end of the cantilever wiggle around relative to the coils which are fixed to the body. These wiggling movements induce a tiny voltage in the coils as they move relative to them.
In an mc, the coils are fixed to the cantilever and a strong magnet is fixed to the body. Same principle, its just the coils that wiggle instead. But being attached to the cantilever, the coils have to be smaller and lighter so that the moving mass of the assembly is not too high, with thinner more flexible wires that wont break through wibbling around. So it wont generate as large a voltage. Hence the need for an extra gain stage in the phono stage, or a step up transformer. The advantage of a moving magnet system is that the stylus assembly can be lighter, so it can react to groove modulations faster. The less moving mass there is (especially tip mass) the easier it is for the stylus to change direction, or more precisely the faster it can stop going in one direction, and start going in another direction. The advantage of the moving coil system? Some think it sounds better.
So, this wibbly wobbly stylus has to be controlled. The magnets need to be kept in a relatively stable place in relation to the coils. And it is, via a bush and tie wire.
So what exactly is cartridge compliance, and why should we care?
This is the resistance to movement of the cantilever of a cartridge relative to the generator in the body of the cartridge. Basically, the lower the compliance, the harder it is to move the cantilever in a given direction. Ideally, we want it to go up and down, and left and right. When I say up down left right (a. start.! google that one), this is viewing the motion of the cantilever from the front of the cartridge.
Ideally, the record would be perfectly flat and the cart body perfectly stable so that as every movement of the cantilever is traced, the moving part of the generator and the fixed part of the generator are in exactly the right relative places at all times. But things aren't perfect. So they are not. If compliance was zero, the entire arm would move in the same manner as the cantilever, the magnets and coils in the cart would not move relative to each other, so nothing would come out of the generator.
So, the cantilever has to move relative to the body to generate a signal. It doesn't need to move by much. That movement needs to be controlled to stop the cantilever moving too far too fast and ending up damaged, and this happens in 2 ways. First there is a rubber bush that the cantilever goes through and stops it moving too fast, and secondly, on the back end of the cantilever there is a tie wire which stops it moving too far. The tie wire is fixed to the end of the cantilever, and to either the body of the cart, or if its a detachable stylus, a part of the stylus assembly. So the end of the cantilever can't move beyond a certain point which is defined by the length of the tie wire, which does not stretch. Or isn't supposed to anyway.......
The bush allows movement, the tie wire restricts that movement to keep the cantilever in the right place and stop it moving too far. Both parts form the compliance.
If the bush is really squishy so compliance is high, the cantilever can react faster as there is less restriction on the speed it can move up down left and right. But......... this can feed high frequency oscillations into the arm. Which are in the audible band and can be heard as distortion. So there is a limit to how high the compliance can go
If the bush is less squishy so is low compliance, the cantilever acceleration and movement in the 4 planes is more restricted. This is not to say that its frequency response, or frequency extremes are curtailed, not at all, but it takes more energy to move the stylus in the 4 planes. And it will dump lower frequency and stronger oscillations into the arm. With high compliance, the stylus is easy to move rapidly, rapidly changing direction, flailing madly and relatively freely to keep up with the groove modulations. This kinetic energy it acquires through its mad thrashings, has to go somewhere, and as much as possible has to go into the generator.
with low compliance, it is doing exactly the same, but it generates more force as its harder to move in 4 planes when the harder rubber bush is resisting the movement.
This is where the matching comes into play. As a rule of thumb, high comp carts require less mass in the arm, and low comp carts require more.
Reason being, is that the cart will always be trying to move the arm in one or 2 of the 4 planes, as not all of the kinetic energy the stylus generates goes into the generator. Some of it goes into the cart and arm structure. the heavier the arm is, the harder it is for the cart to move it. The lighter it is, the easier it is.
So. put a low compliance cart in a low mass arm, and the stylus will dump loads of kinetic energy into the arm. Because the mass isn't enough to keep the arm from moving with the cantilever. If the cantilever moves, the arm does too to a degree. It wont allow the cantilever to exert its full range of movement, because it will get dragged along with it past a certain point. Which means the arm will be resonating, which will move the generator relative to the cantilever So it will distort.
Put a high compliance cart in a high mass arm, and the arm will be too heavy for the stylus to drag it with it at the right speed. This will lead eventually the stylus to be moving in a different direction to the arm. As the heavy arm takes more energy to get it moving, and more energy to stop it moving. Say the stylus goes to the left. the arm will eventually go left too, but the stylus might then start going to the right before the arm has got where its going. This means the arm is lagging behind the stylus, and the cart is not generating the signal based just on what it says on the record, but on what the arm is doing too. So it distorts.
Obviously the above scenarios are extreme and unlikely, and apart from the distortion which is real, are just there to illustrate a point. And the point is this.
There needs to be balance. A balance between the mass of the arm to resist the movement of the generator in the cart body relative to the cantilever, and the compliance of the rubber bush and tie wire to resist the movement of the cantilever relative to the arm and the cart body.
Audio Technica, and several other companies did research in the 70s to try to find the ideal equilibrium. It isn't possible to stop some of the kinetic energy escaping and getting into the arm, but a combination of mass and compliance can keep the resonant frequency of the assembly in a range that is the least damaging.
Yamaha arrived at a figure of 14hz, Shure arrived at 10, and Audio Technica at 11. There will probably be more, but I cant remember them off the top of my head. The general consensus is that this resonant figure should be around 12. Ish. And there is a very useful resonance calculator on the vinyl engine to give an idea of what to expect.
Now the thing is, this concept of arm/cart matching is not make or break, the arm and cart will still work perfectly well if they are mis matched. But if they are matched, there will be better sound quality. The frequency extremes, bass especially seems to go to pieces in a mismatch, wether its high comp high mass or low comp low mass. In my experience bass becomes flabby, one note and boomy, the top end becomes dull and loses its clarity, and the mid where the voices are becomes dull and lifeless.
In a matched combination the sparkle and life comes back, and so does the clarity. Everything firms up. The music returns.
There are of course always exceptions, a friend of mine swears by the Denon DL103 low compliance cart in a Mayware Formula 4 arm which is low mass. It did nothing for me when I tried it, but he likes it so who am I to tell him he is wrong? And the AT440 MLB in my JVC arm should not really work, but the q damping means that it does very well. Although this is with a very light headshell which reduces the effective mass of the arm, and brings the counterweight in almost onto the arm pillar, which lowers the effective mass again. I even found out some very light weight plastic bolts to fix it with to get the mass as far down as I possibly could.
A potential fly in the ointment is that the compliance figure that a manufacturer will give can occasionally be misleading. An example is the Audio Technica AT150sa I have in my Lenco. The quoted figure is 10 x 10-6 dyne. The problem with this figure is that it is quoted at 100hz. Pretty much the rest of the world quotes their figures at 10hz. Audio Technica and Denon do this, I'm not sure wether its a Japanese standard. There will be others I don't know about so it's always worth checking.
To convert the figure into a useable number (although it will be rough it will give a good idea) it needs to be multiplied by 1.75. this gives us 17.5 x 10-6 dyne. As it is a rough number, I will usually put the figure as being between 18 and 20 which is good enough to use to give an idea as to wether it will be a good match.
Using the nice little calculator on the vinyl engine, using the figure of 18, and the effective mass of 6g that my AT1100 has, puts us right in the sweet spot. And it sounds just as sweet as the graph suggests.
Input the figures for an rb250 and it looks marginal, and suggests a potential mismatch. Which tallies with what I heard from it in the RB251 I had. Not that it was bad, but that it wasn't performing as well as it could.
Put in the figures for a Mayware and a DL103, and it looks awful. Like I said, there's always an exception to a rule.
Most carts these days could be classed as medium compliance and have 10hz figures of between 9 and 14, and most arms could be classed as medium mass, with figures of between 10 and 14g effective mass. Which makes life easier. But the plethora of old tonearms and carts that have shown up in online market places over the last year or so following the vaunted vinyl revival create a minefield. You might buy something like a Grace G707 and stick it on your planar (you could you know, its the same spindle to pivot distance.....) because it looks lovely, then put a DL103 on it because some bloke on a forum said it was brilliant.... And be rather disappointed with the results.
It pays to consider these things before sticking your hand in your pocket.
Me personally, I'm sold on the high compliance low mass approach, I have the most musical sound I have ever had with the AT440 on the JVC and the AT150 in the AT1100. And I have had some very expensive MC carts.
Hearing a Linn Ekos with an Ortofon Kontrapunkt B in it on one of my decks at the side of a Mayware formula 4 and AT440 on an identical one of my decks was the clincher. The Linn/Ortofon combo was very very good indeed in a hifi sort of way. Very detailed, open and clean (I like clean very much) but the AT440/Mayware combo was far more musical. And I can't define 'musical', it's a term bandied around too much that means nothing from one person to another. But it grabbed my attention where the Linn/Ortofon didn't
Just don't dismiss high compliance carts out of hand when looking to spend on a new cart.
And do consider the matching of arm and cart, it could quite possibly get you from a good combo to a great one.
And if you are still here after all that, reading this, you are quite possibly as mad as I am........
One high mass arm, off a lenco GL75, effective mass of 23g. Stick a DL103 in this one but put new v blocks in first.........
This is a very thorny issue that can cause arguments to rage on for ages.
The interesting thing is that the arguments rage on about the minutae rather than the overarching concept.
To start with, the basics have to be addressed.
First, how does the cartridge work?
There are two fundamental parts. First the coils, then the magnets. In a moving coil, as the name suggests, the coils move. In a moving magnet, the magnets move. Both have the same parts. In an mm, the magnets are fixed to the cantilever, the cantilever has the stylus on the end of it, and this traces the groove. When it does this, the magnets on the other end of the cantilever wiggle around relative to the coils which are fixed to the body. These wiggling movements induce a tiny voltage in the coils as they move relative to them.
In an mc, the coils are fixed to the cantilever and a strong magnet is fixed to the body. Same principle, its just the coils that wiggle instead. But being attached to the cantilever, the coils have to be smaller and lighter so that the moving mass of the assembly is not too high, with thinner more flexible wires that wont break through wibbling around. So it wont generate as large a voltage. Hence the need for an extra gain stage in the phono stage, or a step up transformer. The advantage of a moving magnet system is that the stylus assembly can be lighter, so it can react to groove modulations faster. The less moving mass there is (especially tip mass) the easier it is for the stylus to change direction, or more precisely the faster it can stop going in one direction, and start going in another direction. The advantage of the moving coil system? Some think it sounds better.
So, this wibbly wobbly stylus has to be controlled. The magnets need to be kept in a relatively stable place in relation to the coils. And it is, via a bush and tie wire.
So what exactly is cartridge compliance, and why should we care?
This is the resistance to movement of the cantilever of a cartridge relative to the generator in the body of the cartridge. Basically, the lower the compliance, the harder it is to move the cantilever in a given direction. Ideally, we want it to go up and down, and left and right. When I say up down left right (a. start.! google that one), this is viewing the motion of the cantilever from the front of the cartridge.
Ideally, the record would be perfectly flat and the cart body perfectly stable so that as every movement of the cantilever is traced, the moving part of the generator and the fixed part of the generator are in exactly the right relative places at all times. But things aren't perfect. So they are not. If compliance was zero, the entire arm would move in the same manner as the cantilever, the magnets and coils in the cart would not move relative to each other, so nothing would come out of the generator.
So, the cantilever has to move relative to the body to generate a signal. It doesn't need to move by much. That movement needs to be controlled to stop the cantilever moving too far too fast and ending up damaged, and this happens in 2 ways. First there is a rubber bush that the cantilever goes through and stops it moving too fast, and secondly, on the back end of the cantilever there is a tie wire which stops it moving too far. The tie wire is fixed to the end of the cantilever, and to either the body of the cart, or if its a detachable stylus, a part of the stylus assembly. So the end of the cantilever can't move beyond a certain point which is defined by the length of the tie wire, which does not stretch. Or isn't supposed to anyway.......
The bush allows movement, the tie wire restricts that movement to keep the cantilever in the right place and stop it moving too far. Both parts form the compliance.
If the bush is really squishy so compliance is high, the cantilever can react faster as there is less restriction on the speed it can move up down left and right. But......... this can feed high frequency oscillations into the arm. Which are in the audible band and can be heard as distortion. So there is a limit to how high the compliance can go
If the bush is less squishy so is low compliance, the cantilever acceleration and movement in the 4 planes is more restricted. This is not to say that its frequency response, or frequency extremes are curtailed, not at all, but it takes more energy to move the stylus in the 4 planes. And it will dump lower frequency and stronger oscillations into the arm. With high compliance, the stylus is easy to move rapidly, rapidly changing direction, flailing madly and relatively freely to keep up with the groove modulations. This kinetic energy it acquires through its mad thrashings, has to go somewhere, and as much as possible has to go into the generator.
with low compliance, it is doing exactly the same, but it generates more force as its harder to move in 4 planes when the harder rubber bush is resisting the movement.
This is where the matching comes into play. As a rule of thumb, high comp carts require less mass in the arm, and low comp carts require more.
Reason being, is that the cart will always be trying to move the arm in one or 2 of the 4 planes, as not all of the kinetic energy the stylus generates goes into the generator. Some of it goes into the cart and arm structure. the heavier the arm is, the harder it is for the cart to move it. The lighter it is, the easier it is.
So. put a low compliance cart in a low mass arm, and the stylus will dump loads of kinetic energy into the arm. Because the mass isn't enough to keep the arm from moving with the cantilever. If the cantilever moves, the arm does too to a degree. It wont allow the cantilever to exert its full range of movement, because it will get dragged along with it past a certain point. Which means the arm will be resonating, which will move the generator relative to the cantilever So it will distort.
Put a high compliance cart in a high mass arm, and the arm will be too heavy for the stylus to drag it with it at the right speed. This will lead eventually the stylus to be moving in a different direction to the arm. As the heavy arm takes more energy to get it moving, and more energy to stop it moving. Say the stylus goes to the left. the arm will eventually go left too, but the stylus might then start going to the right before the arm has got where its going. This means the arm is lagging behind the stylus, and the cart is not generating the signal based just on what it says on the record, but on what the arm is doing too. So it distorts.
Obviously the above scenarios are extreme and unlikely, and apart from the distortion which is real, are just there to illustrate a point. And the point is this.
There needs to be balance. A balance between the mass of the arm to resist the movement of the generator in the cart body relative to the cantilever, and the compliance of the rubber bush and tie wire to resist the movement of the cantilever relative to the arm and the cart body.
Audio Technica, and several other companies did research in the 70s to try to find the ideal equilibrium. It isn't possible to stop some of the kinetic energy escaping and getting into the arm, but a combination of mass and compliance can keep the resonant frequency of the assembly in a range that is the least damaging.
Yamaha arrived at a figure of 14hz, Shure arrived at 10, and Audio Technica at 11. There will probably be more, but I cant remember them off the top of my head. The general consensus is that this resonant figure should be around 12. Ish. And there is a very useful resonance calculator on the vinyl engine to give an idea of what to expect.
Now the thing is, this concept of arm/cart matching is not make or break, the arm and cart will still work perfectly well if they are mis matched. But if they are matched, there will be better sound quality. The frequency extremes, bass especially seems to go to pieces in a mismatch, wether its high comp high mass or low comp low mass. In my experience bass becomes flabby, one note and boomy, the top end becomes dull and loses its clarity, and the mid where the voices are becomes dull and lifeless.
In a matched combination the sparkle and life comes back, and so does the clarity. Everything firms up. The music returns.
There are of course always exceptions, a friend of mine swears by the Denon DL103 low compliance cart in a Mayware Formula 4 arm which is low mass. It did nothing for me when I tried it, but he likes it so who am I to tell him he is wrong? And the AT440 MLB in my JVC arm should not really work, but the q damping means that it does very well. Although this is with a very light headshell which reduces the effective mass of the arm, and brings the counterweight in almost onto the arm pillar, which lowers the effective mass again. I even found out some very light weight plastic bolts to fix it with to get the mass as far down as I possibly could.
A potential fly in the ointment is that the compliance figure that a manufacturer will give can occasionally be misleading. An example is the Audio Technica AT150sa I have in my Lenco. The quoted figure is 10 x 10-6 dyne. The problem with this figure is that it is quoted at 100hz. Pretty much the rest of the world quotes their figures at 10hz. Audio Technica and Denon do this, I'm not sure wether its a Japanese standard. There will be others I don't know about so it's always worth checking.
To convert the figure into a useable number (although it will be rough it will give a good idea) it needs to be multiplied by 1.75. this gives us 17.5 x 10-6 dyne. As it is a rough number, I will usually put the figure as being between 18 and 20 which is good enough to use to give an idea as to wether it will be a good match.
Using the nice little calculator on the vinyl engine, using the figure of 18, and the effective mass of 6g that my AT1100 has, puts us right in the sweet spot. And it sounds just as sweet as the graph suggests.
Input the figures for an rb250 and it looks marginal, and suggests a potential mismatch. Which tallies with what I heard from it in the RB251 I had. Not that it was bad, but that it wasn't performing as well as it could.
Put in the figures for a Mayware and a DL103, and it looks awful. Like I said, there's always an exception to a rule.
Most carts these days could be classed as medium compliance and have 10hz figures of between 9 and 14, and most arms could be classed as medium mass, with figures of between 10 and 14g effective mass. Which makes life easier. But the plethora of old tonearms and carts that have shown up in online market places over the last year or so following the vaunted vinyl revival create a minefield. You might buy something like a Grace G707 and stick it on your planar (you could you know, its the same spindle to pivot distance.....) because it looks lovely, then put a DL103 on it because some bloke on a forum said it was brilliant.... And be rather disappointed with the results.
It pays to consider these things before sticking your hand in your pocket.
Me personally, I'm sold on the high compliance low mass approach, I have the most musical sound I have ever had with the AT440 on the JVC and the AT150 in the AT1100. And I have had some very expensive MC carts.
Hearing a Linn Ekos with an Ortofon Kontrapunkt B in it on one of my decks at the side of a Mayware formula 4 and AT440 on an identical one of my decks was the clincher. The Linn/Ortofon combo was very very good indeed in a hifi sort of way. Very detailed, open and clean (I like clean very much) but the AT440/Mayware combo was far more musical. And I can't define 'musical', it's a term bandied around too much that means nothing from one person to another. But it grabbed my attention where the Linn/Ortofon didn't
Just don't dismiss high compliance carts out of hand when looking to spend on a new cart.
And do consider the matching of arm and cart, it could quite possibly get you from a good combo to a great one.
And if you are still here after all that, reading this, you are quite possibly as mad as I am........
One high mass arm, off a lenco GL75, effective mass of 23g. Stick a DL103 in this one but put new v blocks in first.........
One low mass arm, an Audio Technica AT1100, effective mass of 6g. Put an Audio Technica vm series cart in it or one of their predecessors, or a Grado. Most AT carts will be ok in this one
And a medium mass arm. A Rega RB series arm. Effective mass of 11g. A jack of all trades but master of none. Put something relatively modern in it, something like an Ortofon 2m blue. Or a 1042 if you can stand it........