What Is a Tonearm Counterweight?
The counterweight is one of the most critical components of any tonearm. Fitted to the rear stub of the tonearm tube, it balances the headshell and cartridge at the front, allowing precise stylus tracking force to be dialled in. Using the correct counterweight mass for your cartridge weight is essential: a weight that is too light cannot achieve balance, while one that is too heavy sits too far forward on the stub, raising the tonearm's effective mass and potentially causing resonance problems.
Pro-Ject Counterweight Code 181, 120g
This is a genuine Pro-Ject spare counterweight with model code 181, weighing 120g. Pro-Ject assigns a unique numeric code to each counterweight variant, allowing customers and dealers to identify the correct replacement for a given tonearm. The 181 code identifies the specific bore diameter, thread pitch and mass required by compatible Pro-Ject Evolution series tonearms.
Pro-Ject supplies multiple counterweight options for each tonearm model to accommodate the wide range of cartridge weights available on the market. Choosing the counterweight that sits closest to the bearing block when balanced provides the lowest effective mass and the best sonic performance.
Installation
Thread the counterweight onto the rear stub of the tonearm and position it so the arm balances at the pivot with the anti-skating set to zero and the tracking force dial at zero. Once balanced, rotate the tracking force scale ring to zero before dialling in your cartridge's recommended tracking force. Always refer to your tonearm's instruction manual for full setup guidance.