Phono Stage upgrade to complement Dohmann Helix One Mk 2

@mijostyn 

Sounds interesting, but I would think that it would be simplest to use a lighter cartridge mouting plate and move the counter weight forward based on that as opposed to adding a heavier counter weight, which would then affect the effective mass of the tonearm in a more difficult way.  

The Schroder CB manual says that the effective mass of the 11 inch tonearm is 17g.  However, it doesn't say at which distance from the bearing housing that calculation is based upon, but I guess it doesn't matter that much.  So, getting a heavier counter weight would allow me to place it closer to the pivot point, but then that would lower the effective mass of the tonearm, which would affect the interaction with the compliance of the cartidge.  I don't see how a tonearm with a lower effective mass is neccessarily better than a tonearm with a slightly higher effective mass. 

Does the CB manual state whether the value of 17g is inclusive of the weight/mass of a "typical" cartridge and mounting hardware?  If not, then add the weight of the cartridge plus hardware to the figure of 17g.  I enjoy the math and science of this stuff, but in all honesty, on a personal level, just make it work and enjoy yourself.  I don't know where you were going with your question about the brass, but for sure the material used for the CW makes no difference to SQ.  The density of the metal might come into play where you are concerned about the size of the CW, in order so it fits as close as possible to the pivot.  In that case, density is the parameter to go by, but at the same time, I say don't bother.

@drbond, ​​@lewm is correct. However the critical issue here is the resonance frequency of the tonearm-cartridge combination. A given cartridge is going to require an arm of a given effective mass. Since you can not adjust the cartridge you adjust the effective mass of the tonearm. In the case of the Schroder CB you can do this with different mass cartridge mounting plates and different mass screws or even headshell weights. You then position the counterweight to achieve the correct VTF. With the Schroder you have the choice of several counterweights. With a heavier counterweight you will move it closer to the pivot to achieve the same VTF. This also keeps the arm's effective mass exactly the same, but what it does do is decrease the arms moment of inertia which improves the arms ability to track warps and eccentricities. 

Never set up an arm by specification. Set up and arm by testing. Equations are close to worthless when it comes to adjusting the resonance frequency of a cartridge-arm combination. There are too many variables involved. The specifications are ballpark only. You get a good test record and learn exactly what the resonance frequency is and make adjustments as required. I always shoot for 8 Hz and will settle for a little below but never higher. I also balance my own wheels.

@mijostyn 

Ah, so that makes more sense:  you're not looking to necessarily change the effective mass of the tonearm, just its tracking ability, by decreasing its inertia.  

What type of terst record do you use to measure the resonance frequency of your set up?  (I don't think that the AnalogMagik does a good job at determining resonance frequencties, as every reading I've gotten from that portion of the software is way off the charts, in which case it says that the result is worthless.)

@drbond , The Hi Fi News Analog Test Record. You will know when you hit the resonance frequency because the tone will warble. You might even see the tonearm shake.

Off topic a bit. I have been using ESLs since 1979. I now have 8 foot 645's. Roger West calls them 645-8s. ESLs HATE making bass. They will do it in a very lumpy fashion but it adds significant distortion to everything else. You get away with it only if you listen to less aggressive music at lower volumes, less than 80 dB. However Pink Floyd at 95 dB, forget it. You really need to get 4 subwoofers. It is a PITA and you have to make some other changes but I would NEVER use ESLs without them. It is like putting turbos in a 911. 

Back on topic. You really need to look into the Channel D Seta L 20 Phono stage. It is an insane piece of gear. It has the lowest signal to noise ratio of any phono stage on the market, a lot lower. It will run any cartridge made in either Voltage, Current or MM mode. It will use digital RIAA correction and you can record anyones special records to a hard drive in 24/192. Everyone I have run an AB between the vinyl and it's recording can not tell the difference. I have The Seta L Plus the L20's little brother. Just because I am running very low impedance cartridges in current mode, it is the best sounding phono stage I have ever heard in my system. The L20 is 12 dB quieter!! That is just a stunning figure. I have trouble running the MC diamond running into noticeable noise at higher volumes. I hope to get myself an L20 in the future. Channel D will give you 80% of the price on trade in. The L20 is $50,000. My problem is getting it by the wife. I will have to give her a detached garage, new windows and a new paver driveway first. My Atma-Sphere MA2 amplifiers cost me a hot tub with landscaping. Being married is very expensive. Being alone is worse.