Guides & Articles

The MC Sensitivity

Moving Coil (MC) cartridges are far more sensitive than their MM counterparts. They produce very low output voltages, requiring more gain from the phono stage and much more precise geometric alignment.

A minor error that might go unnoticed with an MM will smear the soundstage and distort the highs on an MC.

1. Geometric Alignment

George Counnas emphasizes that the stylus must sit "perfectly" in the groove.

• Overhang: Use a high-quality protractor. The stylus must track the arm's arc without deviation.

• Azimuth: Viewed from the front, the cartridge must be perfectly vertical to the record. Even a slight tilt will cause channel imbalance and ruin stereo separation.

2. Tracking Force (VTF) Don't be afraid of weight! George advises staying towards the upper limit of the manufacturer's range. If a cartridge specifies 1.8g to 2.2g, set it at 2.1g or 2.2g. A "light" stylus that loses

contact with the groove walls causes significantly more record wear than a slightly heavier one that stays seated.

3. VTA (Vertical Tracking Angle) This refers to the tonearm height.

• George’s Tip: Start with the tonearm parallel to the record surface. If the sound is too thin or "etched," slightly lower the rear of the arm. If it's too dark or muffled, raise it. MC cartridges are extremely sensitive

            to these micro-adjustments.

4. The Critical Setting: Loading (Input Impedance) This is where Zesto Audio excels. MC cartridges require "loading" to prevent high-frequency ringing.

• How to set it: Start with the manufacturer's recommendation (typically 100-500 Ohms).

• The Secret: George Counnas suggests trusting your ears. If the sound is too bright or "thin," increase the loading (lower the Ohms). If it's too closed-in, give it "air" by increasing the Ohms. Zesto Phono Stages

            allow you to adjust this on-the-fly, so you can hear the change instantly.

5. Cleanliness & Static An MC cartridge amplifies everything, including noise. A pristine record and a clean stylus are mandatory to ensure you hear the music, not the dust.

Step-Up Transformer (SUT) – The "Silent" Power of MCs

For many analog purists, a Step-Up Transformer (SUT) is the ultimate way to amplify the tiny signal of an MC cartridge before it reaches the Phono Stage.

• What is an SUT: Unlike an active preamplifier that uses transistors or tubes to provide Gain, an SUT is a passive transformer. It increases the signal voltage using purely magnetic induction.

• Why choose it: The primary benefit is absolute silence. Since there is no active electrical circuit powered by a wall outlet, an SUT adds zero electronic hiss or noise. It is the cleanest form of amplification possible.

• George Counnas’ Approach: George believes that transformers offer a more organic and musical texture to the sound. In Zesto Audio Phono Stages, the MC input passes through high-quality Step-Ups, combining

           passive purity with active tube preamplification.

• Matching is Key: Using an external SUT requires careful matching with your cartridge's internal impedance. When you find the right SUT for your MC, the dynamics and micro-detail will be breathtaking.