Adding more weight to tonearm counterwieght

[Sal1011]

Is there any positive (or negative) consequence to be able increase the weight of the counterwieght to move it closer to the pivot? I have a Fluance RT 85 (obviously not high end) using a solid cherry wood head shell with a Denon dl 103 through an ifi 3 phono preamp. The obvious thing is to clarify the sound with what equipment I have. Point is, the sound stage is more focused and detailed having added 2 ounces of electric tape to the counterwieght and it tracks the natural warps better without wavers, especially in piano. However, it seems so easy to be convinced things are better when really it may be only different. Having said that, the sound really does seem more honest, but what is the science?

 

[DasguteOhr]

Is there any positive (or negative) consequence to be able increase the weight of the counterwieght to move it closer to the pivot?

Positive because you improve the tonearm's moment of inertia. The cartridge will follow the groove better (higher amplitude). You can use cartridges with higher stylus compliance without any problems. But always keep an eye on the resonance frequency so it doesn't get too far into the audible range and always stay below 13 Hz. There are plenty of test records with tonearm-cartridge resonance tests to control this.
Good luck have fun.

 

[Sal1011]

Btw, it occurred to me to increase the counterwieght weight while using a Grado Platinum 3 which is clearly more compliant and heavier than the tonearm appreciated, and also more negatively reactive to warps, which clearly changes the sound. However, my Denon 103 always seemed more honest, and though changing the weight definitely improved the performance of the Grado, it improved the Denon as well and in fact, to my mind, made it superior to the Grado. It's important for less economically well off audiophiles to find ways to improve the sound. I inexpensively wrapped the the plinth in veneer, not only for looks but anti resonance.

 

[Sal1011]

Positive because you improve the tonearm's moment of inertia. The cartridge will follow the groove better (higher amplitude). You can use cartridges with higher stylus compliance without any problems. But always keep an eye on the resonance frequency so it doesn't get too far into the audible range and always stay below 13 Hz. There are plenty of test records with tonearm-cartridge resonance tests to control this.
Good luck have fun.

What would you say would be the 1st audible indication of having raised the resonance frequency above 13 hz?

 

[Sal1011]

What would you say would be the 1st audible indication of having raised the resonance frequency above 13 hz?

 

[DasguteOhr]

What would you say would be the 1st audible indication of having raised the resonance frequency above 13 hz?

This is usually noticeable when the bass drivers of your speakers oscillate uncontrollably even when there's no music. This puts unnecessary strain on the amplifier and increases distortion. It depends on whether there's a subsonic filter (RIAA) or whether the amplifier even transmits below 20 Hz.
cartridge and tonearm is mass spring system when it swings into an area that transmits your signal chain is very bad can possibly destroy your speakers

 

[Don_Camillo]

Positive because you improve the tonearm's moment of inertia. The cartridge will follow the groove better

Yes, but I like to add that a cartridge which requires the counterweight to slide further back adds some additional weight to the effective tonearm mass; increasing the counterweight's weight balances things out somewhat. However, the closer the counterweight gets to the pivot, the smaller the moment of intertia in the pivot and the smaller tracking distortion gets.

 

[Don_Camillo]

What would you say would be the 1st audible indication of having raised the resonance frequency above 13 hz?

Sound switches to the bright side and depending on cartridge compliance and signal to noise ratio of your turntable it starts slightly to bounce even in the quiet passages of the record

 

[DasguteOhr]

Yes, but I like to add that a cartridge which requires the counterweight to slide further back adds some additional weight to the effective tonearm mass; increasing the counterweight's weight balances things out somewhat. However, the closer the counterweight gets to the pivot, the smaller the moment of intertia in the pivot and the smaller tracking distortion gets.

I use several counterweights on my self-built tonearm, the heaviest one closest to the bearing pivot point. If the stylus compliance is low, I can use three; I've had very good experiences with them.

 

[mtemur]

You can use cartridges with higher stylus compliance without any problems.

No, it’s actually the opposite. Increasing the effective mass of the tonearm allows for the use of lower compliance cartridges.

But always keep an eye on the resonance frequency so it doesn't get too far into the audible range and always stay below 13 Hz.

Wrong again. When the effective mass (or total mass) increases for a given cartridge, the resonance frequency of the system decreases. So if it’s in the desired 8-12Hz range it doesn’t go up to 13 Hz, it goes down.

However, the closer the counterweight gets to the pivot, the smaller the moment of intertia in the pivot and the smaller tracking distortion gets.

Good explanation IMO but I’m not sure about the tracking distortion.

Sound switches to the bright side and depending on cartridge compliance and signal to noise ratio of your turntable it starts slightly to bounce even in the quiet passages of the record

I agree that the sound becomes brighter, but I don’t think stylus bouncing occurs with every tonearm and cartridge.

Dear @Sal1011,
The effect you’re hearing is mostly due to the damping caused by the electrical tape you added to the counterweight. The increased effective mass also plays a role, but in my opinion, the damping from the tape is the main reason. I can’t say definitively whether it’s right or wrong—but probably wrong. That said, if it’s fixing the problem, then fine.

 

[Mike Lavigne]

with the Durand arms there is a spendy option for a more dense material for counterweights. which i transitioned to on my Telos Sapphire tonearm back 10 years ago. the design of the shape of the weight was the same, but it's greater density upped the performance of the arm. later i also did that upgrade for the standard Tosca arm with the same result.

and now finally there is the Tosca Limited Edition with the bearing made out of that denser material (unobtainium) and the same material for the weights but using a sapphire sleeve. again, another performance boost.

so the material used for a counterweight and it's characteristics and mechanical solidity of the whole package can have a significant effect on performance.

among other attributes of a denser, heavier weight......is that it is closer to the pivot point for the same cartridge mass. so that is part of the picture.

 

[DasguteOhr]

No, it’s actually the opposite. Increasing the effective mass of the tonearm allows for the use of lower compliance cartridges.

First,you should read correctly, i never say one word to effective mass.It's about moment of inertia. this has nothing to do with effective mass but acceleration of mass.

Wrong again. When the effective mass (or total mass) increases for a given cartridge, the resonance frequency of the system decreases. So if it’s in the desired 8-12Hz range it doesn’t go up to 13 Hz, it goes down.

and again misread and twisted my words. I give up.

 

[DasguteOhr]

The "effective mass" of a tonearm can also be determined experimentally.
You will need:
- Spring wire
- Postal scale
- Modeling clay
- Tripod
- (Stop) watch
The "effective" mass is called that because the effective mass is being sought on the headshell. This depends on the rotational moment,... blah blah, etc. Most people know this, and you can read about it everywhere.

The practical part:
You need a (tension) spring (wind it yourself?!), which is attached to the headshell so that your arm can swing freely on the spring. The spring should be attached to a tripod (table lamp?). Now count the number of vibrations the arm makes on the spring in a defined time (30 seconds?). Write it down, remember it,...
Then remove the arm from the spring and hang a weighed ball of modeling clay (10g?) on the spring instead. Again, you count the oscillations per unit of time. It will be different the first time, so you'll need to increase or decrease the clay until the oscillation period is identical to the arm/spring combination.
Once you've reached a match, all you need to do is weigh the clay and you'll have the effective mass of your arm.