The Pro-Ject 120g Counterweight (004) is a genuine replacement counterweight for Pro-Ject tonearms identified by part code 004. Counterweights are fitted to the rear stub of the tonearm tube and allow the user to set the correct vertical tracking force for the cartridge; without the correct balance, the stylus will either press too hard into the groove, risking record wear and distortion, or too lightly, causing mistracking.
Why the Correct Counterweight Matters
Each Pro-Ject replacement counterweight is identified by a three-digit code stamped on the body; this unit carries the code 004 and weighs 120g. The mass of the counterweight determines the range of cartridge weights it can balance: a heavier counterweight is required to balance lighter cartridges, while a lighter counterweight suits heavier cartridges. Fitting the correct counterweight ensures the body sits close to the tonearm bearing when tracking force is set, which reduces the risk of resonance from a rearward-displaced weight.
Installation and Setup
The counterweight slides onto the rear of the tonearm tube and is secured with a grub screw. Once in place, tracking force is dialled in by rotating the counterweight along the tube. Pro-Ject recommends re-checking tracking force and stylus alignment whenever a cartridge or counterweight is changed. This counterweight is supplied as a spare part; check the three-digit code stamped on your existing counterweight before ordering to confirm compatibility.