Mo’ Mass

Galibier Design - Kuzma 4Point-9 with Brass Headshell Weight

4Point-9 with brass headshell shim

How much is too much?

Recent experiments with the Kuzma Safir arm (60 g. effective mass) inspired us document some ongoing mass mass experiments we've been undertaking.

If you're not aware, we released a headshell shim kit last year for this purpose - a kit that also includes an angled shim to address SRA issues.

Update:  27-June-2024

After posting this, a paper from Franc Kuzma was brought to our attention.  While it primarily relates to the Safir-9 tonearm, it has some general comments on mass, as well as why many modern turntables can "tolerate" higher mass arms.  

It's a good, short read.  Click here to view it.

An Unlikely Candidate

The Kuzma CAR 40 (as are all Kuzma cartridges) is quite the beast - weighing in at 17.5 grams.

It was an unlikely candidate for these experiments, but what better way to explore its limits?

Our heavy brass shim adds 8.25 grams to the 4Point-9's 13 grams, which in combination with this cartridge's hefty weight stretched the limits of the 4Point-9's counterweight.

We pressed a 4Point-11 accessory counterweight into service to balance out the arm.

Behold!  A Mass Tuning Kit

In the photo, you'll note the 4Point-11 accessory counterweight at the end of the arm stub.

This experiment inspired us to release a heavy rear counterweight section to mate with the 4Point-9's larger front half.

We'll be bundling this counterweight along with our brass headshell weight as a mass tuning package.

We encourage you to experiment, to the limits of the adjustment range of your arm.

The old college method of affixing a coin on your headshell will do.  A nickel (or two) affixed with some Blu Tack will suffice. 

Remember to reset your tracking force!

Galibier Design - Kuzma 4Point-9 with Extra Counterweight

4Point-11 counterweight added

And on a Schröder ...

Galibier Design - Schröder CB with Brass Headshell Weight

brass headshell shim + heavy carrier

Next up, was a Hana Umami Blue on our Schröder CB-9.

We had already employed the heavy brass cartridge carrier which brings the CB's mass to 19g.  

Adding our brass shim brought the mass up to 27.25g.

The Schröder's arm stub/counterweight had enough adjustment range for the slightly lighter Umami Blue (10.8g).

Stay tuned for an "extra-heavy" Schröder carrier, using the same brass Frank uses.

This heavy carrier will add a 24 gram option to the CB-9's 14 & 19 gram selections (Certal and brass carriers).

One Consideration

If you have a suspended turntable, this 8-10 Hz target may be more significant, but this is an easy enough experiment to carry out.  

If your bass quality muddies up (and "slows" down), then this is either stretching the mass compatibility range of your cartridge, or resonances are building with your suspension.

It's an easy enough experiment to back out of with some Blu Tack and a nickel or two.  BTW, a nickel weighs 5 grams.

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Thom


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