Accessories

Turntable Test Vinyl Record - Laboratory Edition WT-2.

The Unitra’s Laboratory Edition vinyl test has been specially designed to enable verification of hi-fi audio equipment in conditions of everyday use, where we listen to music most often, i.e. at home. The Laboratory version is intended for the most demanding users and enthusiasts of high-end devices. The set includes two black vinyls containing advanced test signals developed by Unitra experts. The records enable accurate measurement of various indicators used to calibrate the performance of the phono cartridge. The calibration disc can be used with the Unitra GSH-630 Fryderyk and GSH-801 Edmund turntables, but also with any other device available on the market.

Expertise and experience.

The Laboratory version, like the less advanced Standard vinyl, was created in cooperation with a Polish company. It combines extensive knowledge and experience in the field of analog sound. Its creation would not have been possible without the valuable contribution of recording and mastering engineers. External experts and the experienced team of Unitra engineers, who design turntables on a daily basis, also contributed to this. The goal of all experts involved was to achieve the highest quality and fidelity of stereo reproduction.

Contents of the Laboratory Edition

The set includes:

Arm calibration instructions. This is a detailed step-by-step guide that will help you precisely position your turntable arm. In five steps, from setting the VTA stylus tracking angle, through azimuth, alignment, cartridge pressure and anti-skating.

Calibration template with tracks for precise anti-skating adjustment that takes into account the friction force not on the plane, but also in the groove.

Black vinyl with side A and B

Black vinyl with side C and D - both discs are standard media with better sound quality.

Side A

Track 1. 20 Hz – 20 kHz log −20 dB

Track 2. 20 Hz – 15 kHz log −14 dB

Track 3. 20 Hz – 2 kHz log 0dB

This section contains a series of frequency responses to check and plot a cartridge char acteristic. Using different recording levels allows us to have dif ferent frequency range. Maximum continuous high frequency is limited by any vinyl cutting machine (technologic al limit). Low recording level allows to reach higher frequency response but with worse SNR.

Track 4. 30 Hz – 15kHz log −14dB VU [step]

Last track has responses separated by pauses. Recording level 14 dB below standard reference level. Best when using simple method with oscilloscope.

Side B

This side contains a flat surface that allows to check anti-skating operation, and silent groove for turntable isolation testing.

Using alignment protractor on the record or verifying reaction of arm on the flat surf ace allows to set and validate the anti-skating system.

Silent groove track will help you experiment with turntable isolation products and methods so that you can get the most out of your player. You may use closed headphones for the best listening conditions.

Side C

Track 1, 2, 6

Standard wow and flutter test signals (3150 Hz). The wow and flutter meter will report dynamic speed variations as a percentage deviation from the nominal value. The frequency meter should read exactly 3150 Hz for the nominal speed. It can be checked at the beginning and at the end of the record for 33 1/3 RPM, and at the beginning for 45 RPM.

Track 3

1kHz reference tone, 7 cm/s, lateral, in phase (mono). This is the primary reference for all measurements (O VU in the studio), Adjust your preamplifier’s channel balance to obtain an equal output level. Both signals (left and right) should be exactly in phase (see the indication on the oscilloscope).

Track 4, 5

Tracks represent the same signal but on one channel. Crosstalk level measurement is possible or it can also be used to verify if the cantilever is exactly perpendicular in the groove. Rotate the cartridge around its radial axis until the measurements from Tracks 2 and 3 are as low and as even as possible between the two channels.

Side D

Track 1. 20 Hz-15 kHz log -14dB [long]

Frequency response with slow rising and logarithmic scale, A 1 kHz tone is present at the beginning of the track.

Track 2. 20Hz-15kHz lin -14dB [long]

Frequency response with slow rising and linear scale. A 1 kHz tone is present at the beginning of the track,

Track 3. BINBEAT 0dB

Set of frequency modulations that differs on both channels. This setup allows you to check the stability of the stylus tip in the groove.

Track 4. AS 315 Hz up to +10dB [lateral]

Anti-skating test, 315 Hz amplitude sweep to +10 VU, lateral. The signal should remain clean in both channels up to the highest level, as confirmed audibly and viewed on an oscilloscope. If distortion occurs, increase or decrease the anti-skating force while ensuring that there is no skipping.

Track 5. AS 1kHz 20dB [horizontal]

1kHz reference tone at -20 VU, vertical. This out-of-phase signal should disappear when summed to mono. Any signals still present are distortion artifacts, channel imbalances or timing (phase) anomalies. This test can be used as a second confirmation of the anti-skating adjustment.

Starting a test

How to set up the turntable before the test?

To properly perform the test with the Laboratory Edition, please carefully read the instructions for the turntable and tonearm. The key is to properly position the arm so that it is parallel to the surface of the vinyl record. The user should also set the pressure force (VTF, Vertical Tracking Force) and anti- skating in accordance with the recommendations of the insole manufacturer.

Recommendations

To maintain optimal sound quality and minimize record and stylus wear, the following procedure is recommended before and after each playback. Before each use, remove dust from the hob surface using a soft antistatic brush or cloth. You also need to remember to clean the stylus before and after each playback of the recording.

Product specification

Specifications

Size: 2x12"

Playback speed: 33 1⁄3

Weight: 140 grams

Type: Classic black vinyl record