The goal of the tonearm is to provide a stable platform for the phono cartridge to track in the groove at the correct geometry. So the first order of business is to set up the tonearm overhang and alignment so that the stylus remains at the tangent point in the groove and aligned square to the groove from start to finish. Next, the tonearm is suspended over the record with near zero friction and coupled to the stylus through a spring suspension. In addition, forces are acting on the stylus in all three dimensions. The stylus is being pushed to the left and right, pulled on and pushed up and down (warps in the record). The tonearm and cartridge system is a classic spring/mass system which responds to this harmonic input. This spring mass system has a resonance point which is where small energy inputs cause large energy outputs. If the tonearm system resonance is too low, ie. less than 8 Hz, it will become sensitive to footfalls and the rotating record. The record is rotating at 0.5555Hz. 10 times that is 5.5555Hz which is a safe range away from resonance. 45 rpm puts the record rotation at 0.75 Hz so 7.5Hz minimum for the tonearm would be a safe range. Much higher than 10 Hz can cause the tonearm to become very lively with warps in the record and is also getting close to the 20Hz signals in the grooves. It may or may not skip but the lows can get muddy because the arm is responding to those low frequency signals in the record grooves. Record runout creates a 0.55Hz at 33 1/3 rpm and 0.75Hz at 45 rpm lateral sway in the tonearm. This is another reason to keep your tonearm/cartridge system response around 10Hz.
Best Counterweight Position?
Some might say "At the opposite end from the head shell" :-)
But how can you be sure if the position that gives you the correct stylus pressure is the best position for your cartridge?
What I recently discovered on my setup is the further back I placed the weight the more lateral resistance was applied to the cartridge, changing the sound for the better.
To accomplish this required me to change the effective mass of the tone arm - several times.
One very simple way to accomplish this was to remove a piece of the outer cable insulation from a thick mains cable. Making a cut down the length of the sleeve allowed me to place it on the arm near the cartridge and the sleeve gripped the arm without allowing any movement.
I then proceeded to recalibrate the tracking force by repositioning the weight more towards the rear of the arm - away from the pivot point
The first attempt made the sound bloated and displayed some nasty effects, so I simply cut off a piece of the Insulation and recalibrated the tracking force.
Once the best sound is achieved you can then make the adjustment permanent by adding a headshell weight that results in the counterweight being placed in the same distance from the pivot point of the arm.
The head shell weight I started with matched the weight of the insulation and then did some fine tuning to get the weight into the correct position.
Now, there are some that will point out that this will change the effective mass of the arm and may upset the delicate balance of tone arm/cartridge compliance matching.
Well, that is true if the cartridge is matched "exactly" to the tone arm, fact is there is most always a fair bit of latitude in this area, allowing for some room for improvement.
If you are of the belief that the effective mass of the arm should not be changed, then, using a lighter counter balance weight will allow you to place it further back.
In my case I have a Rega RB250 and a Denon DL103, which is not "the best" match, but by adding some mass to the tone arm this cartridge really performs extremely well and brought the compliance/tone arm match closer to the recommended settings.
Yes, the compliance match is one reason for the better sound, but getting the counter weight further from the pivot point also made the DL103 perform much better IMHO :-)
What improvements did I notice - much smoother reproduction in the high frequencies, more texture in the bass frequencies, improved imaging and bigger sound.
Cost - just some of my time and the headshell weight, about $10.
Something to try on those cold winter nights :-)
But how can you be sure if the position that gives you the correct stylus pressure is the best position for your cartridge?
What I recently discovered on my setup is the further back I placed the weight the more lateral resistance was applied to the cartridge, changing the sound for the better.
To accomplish this required me to change the effective mass of the tone arm - several times.
One very simple way to accomplish this was to remove a piece of the outer cable insulation from a thick mains cable. Making a cut down the length of the sleeve allowed me to place it on the arm near the cartridge and the sleeve gripped the arm without allowing any movement.
I then proceeded to recalibrate the tracking force by repositioning the weight more towards the rear of the arm - away from the pivot point
The first attempt made the sound bloated and displayed some nasty effects, so I simply cut off a piece of the Insulation and recalibrated the tracking force.
Once the best sound is achieved you can then make the adjustment permanent by adding a headshell weight that results in the counterweight being placed in the same distance from the pivot point of the arm.
The head shell weight I started with matched the weight of the insulation and then did some fine tuning to get the weight into the correct position.
Now, there are some that will point out that this will change the effective mass of the arm and may upset the delicate balance of tone arm/cartridge compliance matching.
Well, that is true if the cartridge is matched "exactly" to the tone arm, fact is there is most always a fair bit of latitude in this area, allowing for some room for improvement.
If you are of the belief that the effective mass of the arm should not be changed, then, using a lighter counter balance weight will allow you to place it further back.
In my case I have a Rega RB250 and a Denon DL103, which is not "the best" match, but by adding some mass to the tone arm this cartridge really performs extremely well and brought the compliance/tone arm match closer to the recommended settings.
Yes, the compliance match is one reason for the better sound, but getting the counter weight further from the pivot point also made the DL103 perform much better IMHO :-)
What improvements did I notice - much smoother reproduction in the high frequencies, more texture in the bass frequencies, improved imaging and bigger sound.
Cost - just some of my time and the headshell weight, about $10.
Something to try on those cold winter nights :-)
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- 13 posts total
- 13 posts total