Cartridge performance

Quality
Assurance

Ortofon test chain
measurement

A PC-based test system

Accurate and reliable
measurements

Our PC-based test system is designed to provide accurate and reliable measurements of cartridge performance. Prior to testing, the cartridge is mounted on a specially optimized headshell to ensure repeatable and reproducible results.

Steps through the chain

The Ortofon
measuring chain

  1. Cartridge mounted in test headshell and/or tonearm
  2. Amplifier with RIAA switch
  3. AD converter
  4. BandPass filter: 6th order Bessel/Butterworth (IIR)
  5. PC (Results for QC)
  6. Store Data on a server

Amplification

To accommodate different impedance characteristics and cartridge types (Moving Magnet or Moving Coil), the cartridge is connected to an amplifier. The amplifier is adjusted for an input impedance of either 100 ohm, 200 ohm, or 47 kohm/220pF (including cable capacitance), depending on the impedance characteristics and type of cartridge. Specifically, for Moving Magnet (MM) cartridges, the signal is amplified with a gain of +40 dB, while for Moving Coil (MC) cartridges, the signal is amplified with a gain of +60 dB.

Switchable RIAA-EQ

Ensuring accurate
meassuremtents

The phono pre-amp allows us to perform measurements with or without RIAA-equalization. For frequencies below 1 kHz, the RIAA equalization curve is set to ON/automatic, ensuring accurate measurements. For high-frequency tests, the switch is set to OFF, allowing maximum bandwidth, as the records used are cut linear and non-equalized.

Storing data

The signal is subsequently converted through an AD-converter and filtered to optimize PC capacity usage. The resulting data is then stored on a server for analysis.

Each MM/MC model is tested using a set of limits that reflect the cartridge's performance.

Three sequences of
the measurement test

In the measurement test, we evaluate sensitivity, channel separation, balance, tracking, and frequency response using Ortofon test records and various filters.

1. Testing sensitivity

Testing sensitivity, channel separation and balance: we use track 5 and 6 (or 7 and 8) on Ortofon test record. The measurements are performed at 1kHz with a speed of 5cm/s RMS. The AD-sampling rate is at 40 kHz, with 500 samples per iteration. The filter is a Butterworth IIR Band Pass of 6th order with cut-off frequencies of 50Hz and 5kHz.

2. Testing tracking

We use track 9-14 on Ortofon test record; track depends on cartridge specifications. Detection of tracking is performed at 315Hz. It is chosen to register on the 4th, 5th, and 6th harmonics in an FFT signal analysis. The filter is similar to what is applied in the first test sequence.

3. Testing frequency response

We use the Ortofon test record 1-4. For this tes, the sampling is performed at 42 kHz, with 500 samples per iteration. The filter is a Bessel IIR Band Pass of 3rd order with cut off frequencies of 800 Hz and 21 kHz.

Test equipment
applied by Ortofon

  • Ortofon test equipment setup

    Record Player: Technics SL-1210GR Vibration damped table: Ortofon Design Headshell: Special Ortofon Design Amplifier: Modified Lehmann Black Cube with a RIAA switch AD converter: National instruments USB-6003 16 bit resolution, sampling rate of 50 kS/s. Program: Special Ortofon design in Labview

    Test records used: Ortofon Test Record. Due to record wear, test records are replaced with a fresh example every month.

    Calibration equipment (subject to changes): Function Generator: RME Adi-2 Pro Fs ADC/DAC. Multimeter/Oscilloscope: RSMSO-2204E

  • The Gauge Repeatability and Reproducibility

    We think the best way to show the product and its technology respect is to test the cartridges on basis of the principles of Repeatability and Reproducibility.

    Ortofon applies the Gauge Repeatability and Reproducibility (R&R) when testing the cartridges. Read more about the principles here.

    Read more