Weiliang Audio U9 a simplified report for non-professional users - Reference Audio Analyzer

Weiliang Audio U9 is available in reports and services. You are in a simple report.

Service and suite of tests

Information for entry level users

report for a newbie
(Headphone amplifier)

General recommendations

The automatic selection of the optimal AMP models

Information for all

Comparison of on-line graphs


Reports / Weiliang Audio / U9 / Amplifier path / report for a newbie

Test report Weiliang Audio U9 (report for a newbie)




This is a simplified report for non-professional users ("dummies"), poorly versed in the headphones characteristics and specialized graphs.

Information in this report presents in most simple and clear as possible. Interpretation of the data is simplified as much as possible and accordingly devoid of subtleties and nuances. This is sufficient for an overall assessment, but for a more complete and accurate presentation, the professional report should be studied.

By possible, the characteristics are accompanied by explanations to do reader possibility gradually master a more complex professional report.

For example when choosing a video card, many people do not understand the set of tables with the final data of the test packages. How to understand the relative difference in these figures? In most cases, the unprepared reader is satisfied with only the textual evaluation of the author, without delving into the figures. When the choice of a product is done thoroughly, then the reader gradually deepens into complex tables, mastering information from simple to complex. We made two separate reports: "simple" and "complex". A simple report with explanatory comments will allow you to self-study to gradually understand and professional report.

General results of the amp part of Weiliang Audio U9

Output Impedance
12.16 ohm

Characteristics for high quality mode

Power characteristics of the Weiliang Audio U9
Headphone impedance, ohm
Power, mW
Voltage, dBV
32
14.92
-3.21
300
76.54
13.61

Recommended impedance for headphones from the range 8 - 1008 ohm
For In-Ear Headphones
8 - 1007 ohm
For Over-Ear Headphones
8 - 614 ohm

Characteristics for the maximum mode

Power characteristics of the Weiliang Audio U9
Headphone impedance, ohm
Power, mW
Voltage, dBV
32
34.96
0.49
300
76.54
13.61

Recommended impedance for headphones from the range 8 - 1008 ohm
For In-Ear Headphones
8 - 1007 ohm
For Over-Ear Headphones
8 - 614 ohm


How to compare amplifiers for loudness

When comparing amplifiers in volume necessary to use a voltage value expressed in dBV. The difference in voltage will show the difference in dB between the amplifiers.

The power values in mW do not have a direct comparison.

The direct power comparison is only suitable for speaker amplifiers operating with an ultra-low-ohmic load. This does not apply to headphone amplifiers where the headphone resistance is higher than 8-16 ohms.

Because of the higher resistance of the headphones, when comparing the volume for a musical signal, it is necessary to simultaneously take into account the current and voltage limits, while the amplifiers for the speakers only have a current limitation. For the exact difference between the amplifiers in dB, the power value must be converted into voltage in units of dBV, taking into account the current margin for the music signal to 12 dB.

If to make a comparison simply by power, then the error will reach up to 12 dB. When sorting by volume, you can see that at the same volume values in dBV, the power values in mW will be different.

What and how to compare with the characteristics of manufacturers

The high-quality mode power is equivalent class A . Typically, manufacturers for this power indicate the percentage of distortion, which should be no more than 1%.



Simply maximum power , this is the power level above which the amplifier is already wheezing or the volume control is already at its maximum. Usually indicated without a percentage of distortion, because а high quality for this value is not implied.

Analysis with recommendations for the Weiliang Audio U9 AMPs path based on the measured characteristics

Analysis and recommendations for Weiliang Audio U9 based on the measured characteristics
Headphones Areas of using headphones Voltage Not loaded Max F.A.Q. / in equal class A F.A.Q., dBV Current in equal class AF.A.Q., dB(mA) Noise Isolation Necessity Total
13.95 /13.95 26.69
In-Ear or Tablet
Sensitivity: 126 dB/V SPL
Impedance : 16 ohm
The type of acoustic design: Closed
Examples ±6 dB
Home or studio, where sound from the headphones does not bother anyone 5
★★★★★
5
★★★★★
1
★☆☆☆☆
3.7
★★★☆☆
Office and home, where people should not hear the sound from the headphones 5
★★★★★
5
★★★★★
5
★★★★★
5.0
★★★★★
Recording a voice or instrument in the studio 5
★★★★★
5
★★★★★
5
★★★★★
5.0
★★★★★
In-Ear or Tablet
Sensitivity: 120 dB/V SPL
Impedance : 32 ohm
The type of acoustic design: Open
Examples ±6 dB
Home or studio, where sound from the headphones does not bother anyone 5
★★★★★
5
★★★★★
5
★★★★★
5.0
★★★★★
Office and home, where people should not hear the sound from the headphones 5
★★★★★
5
★★★★★
1
★☆☆☆☆
3.7
★★★☆☆
Over-ear Low impedance
Sensitivity: 115 dB/V SPL
Impedance : 32 ohm
The type of acoustic design: Closed
Examples ±6 dB
Home or studio, where sound from the headphones does not bother anyone 5
★★★★★
5
★★★★★
1
★☆☆☆☆
3.7
★★★☆☆
Office and home, where people should not hear the sound from the headphones 5
★★★★★
5
★★★★★
5
★★★★★
5.0
★★★★★
Street with active traffic 5
★★★★★
5
★★★★★
1
★☆☆☆☆
3.7
★★★☆☆
Recording a voice or instrument in the studio 5
★★★★★
5
★★★★★
5
★★★★★
5.0
★★★★★
Over-ear Low impedance
Sensitivity: 115 dB/V SPL
Impedance : 32 ohm
The type of acoustic design: Open
Examples ±6 dB
Home or studio, where sound from the headphones does not bother anyone 5
★★★★★
5
★★★★★
5
★★★★★
5.0
★★★★★
Over-ear Hi impedance
Sensitivity: 105 dB/V SPL
Impedance : 300 ohm
The type of acoustic design: Open
Examples ±6 dB
Home or studio, where sound from the headphones does not bother anyone 5
★★★★★
5
★★★★★
5
★★★★★
5.0
★★★★★
Over-ear Low Sensitivity
Sensitivity: 95 dB/V SPL
Impedance : 60 ohm
The type of acoustic design: Open
Examples ±6 dB
Home or studio, where sound from the headphones does not bother anyone 4
★★★★☆
4
★★★★☆
5
★★★★★
4.3
★★★★☆


The table shows the most common variations of sound sources and the scope of use of AMPs and headphones bundles.

The compatibility rating is similar to car analysis based on its ground clearance - on which road the car will move optimal without evaluating the class of the car.

Detailed description formula of the table of AMPs

To assess the compatibility of the amplifier part, we assume that the user will listen to music at a volume level of 90 dB SPL. Depending on external conditions, this volume varies and we estimate the conditions under which the source will play in a high-quality mode, and in which there will be a lack of volume, unnecessary distortions or other negative factors.

Description of the characteristics and recommendations for Weiliang Audio U9 on the table of recommendations


In the table, the characteristics are interpreted and then the ratings are given on a five-point scale. You can see below the more comprehensive analysis of the characteristics by the algorithms used in the table.


The table provides two main estimates for the amplifier: an estimate by current and an estimate by voltage. The characteristics of the headphones and the environment affect the final desired voltage level from the amplifier output, which must provide a sufficiently level of loudness from the headphones.


Main characteristics of the Weiliang Audio U9

The main "universal" characteristics of the amplifier are maximum current, maximum voltage and output impedance.

Значения тока и напряжения может быть разделено по порогам качества.

В общем случае, при увеличении громкости, качество звучания усилителя ухудшается. Примерно как автомобиль с определенной скороcти становится менее управляемым. В этом отчете мы рассматриваем два порога.
  • Режим эквивалентного класса А F.A.Q. - высокое качества (как великолепная управляемость автомобиля на небольшой скорости).
  • Максимальный режим F.A.Q. - предельные характеристики, выше которых усилитель или хрипит или невозможно для него выставить уровень громкости выше (когда автомобиль теряет управляемость выше определенной скорости или не может развить скорость выше).
Voltage
  • The maximum voltage level F.A.Q. without load is 13.95 dBV.
  • The maximum voltage level in equivalent class A F.A.Q. without load is 13.95 dBV.
Уровень сигнала на выходе усилителя регулируется через напряжение. Именно этим параметром управляет регулятор громкости.

Current
  • The maximum current level F.A.Q. without load is 30.38 dB(mA)
  • The current level in equivalent class A F.A.Q. without load is 26.69 dB(mA).
В зависимости от сопротивления подключенных наушников и выставленного напряжения усилитель отдает ток. Уровнь тока пропорционален напряжению, а коэффициентом отношения тока и напряжения является сопротивление наушников как 1/R. Чем выше сопротивление у наушников, тем меньше требуется отдача тока от усилителя.

Impedance
  • The output impedance of the amplifier is 12.16 ohm.
Выходное сопротивление усилителя влияет на амплитуду напряжения с выхода усилителя при подключенных наушниках. Чем выше выходное сопротивления усилителя и ниже сопротивление наушников, тем амплитуда сигнала напряжения на выходе ниже.



Analyse of the output impedance of the Weiliang Audio U9


When load is on (headphones were connected) the output voltage level decreases depending on the output impedance of the amplifier. The Weiliang Audio U9 has an output impedance of 12.16 ohms.

This is a middle-impedance. With this impedance, the voltage drop at a low impedance load is moderate.

For а low-impedance load this is optimal gain margin and drop background noise.


If the voltage is 13.68 at the 600 ohm load, then under load of 16 ohm voltage will decreases by 5.75 dB to 7.93 dBV.


Analysis of voltage and current Weiliang Audio U9 на графике


One of the main tasks of the detection of compatibility of headphones with a specific amplifier, is to find out whether the amplifier can give the optimum voltage level. That section describes with details how to construct a graph of maximum voltage from the music power from the initial parameters of the amplifier.

Based on the values of the maximum voltage F.A.Q. levels and impedance of the amplifier, the maximum voltage levels for the headphone impedances of interest are determined. On the graph in the example, these are the impedance: 16, 32, 70, 150, 300 and 600 ohms. Grey columns show maximum voltage levels.

Voltage values are expressed not in volts, but in decibels to 1 volt - dBV. This allows you to compare the volume immediately in dB, which many are used in the equalizer and while adjust the volume.

We are interested not only in how loud the amplifier can work, but also to determine the range on what volume level we can get good quality. So we make estimation according to the voltage and current data of the in equivalent class A F.A.Q..

The lilac color area shows the voltage range for the equivalent class A under load without current limitation. This region is constructed in the same way as for the maximum voltage, depending on the magnitude of the load. However, each load value requires a certain current level at the output voltage at the amplifier output. Yellow area indicates the voltage range for the equivalent class A under load with only a current limitation with a margin of 12 dB (correction for a musical signal). From two areas, a green area is obtained - a range that enters both the lilac and yellow zones simultaneously. This is the desired range, which is optimal for the amplifier.

The lower bound for the yellow, lilac and green ranges in the form of the minimum voltage value is determined by the maximum level minus 36 dB. It is often believed that the louder the amplifier is the better, but it is not. If the amplifier is excessively loud, then when you lower the volume level, you often have to deal with different problems: audible background noise or channel imbalance.

  • Digital volume control - when the volume is lowered by program way or through the controller in the DAC, the useful signal decreases in amplitude, but the background noise remains at the same level. After lowering the volume to a comfortable level, you can hear definitely clear the noise in high-sensitivity headphones (or in middle- sensitivity headphones if the amplifier is initially very loud / powerful).
    In smart phones, tablets and laptops in the low volume area there can be a noticeable contribution of distortions from the software algorithms of SSRC, which are even more destructive than background noise. Moreover, where volume control is performed through the OS (Windows, Linux), the volume control range may not exceed 48 dB and the user will have a choice between the loud sound and its total absence.
  • Analogue volume control - most analogue controls have an unbalance in the low volume level, when one channel sounds quieter than the other. To obtain a better volume control, use variable resistors from ALPS. In this case, imbalance is observed at much lower volume levels. To obtain maximum quality, discrete regulators (stepped volume control) are used. Но, обычно шаг регулировки в области низких громкости - большой.
It is best to use an amplifier with such a margin in volume that for the headphones used, the range of volume down regulation does not exceed 36 dB.

Thus, the lower level is limited by the recommended volume control range, and the upper level is calculated based on the current and voltage limits in the highest quality mode for this device, which we define as equivalent to class A.


Ваш браузер не поддерживает Canvas

For headphones, based on their sensitivity, ambient conditions and the required volume level, the required voltage is calculated. If the required voltage value is under the green area, then the headphones will be too sensitive for Weiliang Audio U9 and to set the optimum volume level it will be necessary to lower the level by more than 36 dB from the maximum.

If the required voltage value is above the green area, then you have headphones with not enough sensitivity-level and / or amp with insufficient voltage level in the equivalent class A.

If the value is above the green area, but does not exceed the gray area, then the headphones will give the necessary volume level, but the sound will be less qualitative, because the amplifier will work already in less qualitative equivalent modes AB, B and maximum level.

If the value exceeds the maximum level, then the necessary volume level can not be reach, or will be clearly heard the "wheezing sound" from clipping.

The simplified formula of the desired voltage for headphones is as follows:
V = SPL - Sensitivity + Peak factor - Output voltage + Correction for external circumstances
where:
  • SPL - the desired sound pressure in dB SPL at the headphone output.
  • Sensitivity - the sensitivity of the headphones to the voltage.
  • Correction for a music signal of 20 dB to account for the unevenness of the volume on the sound track.
  • Output Voltage - the level of the output voltage of the amplifier in dBV when loaded of the headphone impedance.
  • The correction for external circumstances is the noise of the environment and the presence of noise insulation in the headphones.
Thus, we calculate the star rating for the table. You can study formulas more detailed.

The analysis for specific headphones can be viewed separately by selecting the appropriate headphone models on professional graphics.


Analysis of use Weiliang Audio U9 with headphones of different acoustic design


This rate primarily depends on the acoustic design of the headphones and the field of application of the headphones. Additionally, depending on the acoustic design, a correction is made to calculate the optimum volume level at which headphones are supposed to be used. In closed-type headphones due to noise isolation from outside sounds, the volume level can be slightly reduced, in calculations it is equal to -6 dB.


The table shows the options with closed and open headphones and ratings from 1 or 5.


If in your situation, the Weiliang Audio U9 AMPs path in the table do not have a high rating, you can choose more suitable headphone models in a special on-line selection for the selected parameters. If fully suited, then similarly you can see what other models may suit you.



For different purposes it is best to select individual headphones, and not to search for one universal source for all cases of life. Unfortunately, some properties of headphone amplifiers and headphones mutually exclude the use of the headphones in different situations. True connoisseurs of quality sound use several pairs of both headphones and amplifiers. In contrast to large speakers (speakers), headphones and amplifiers to them are compact and do not take up much space.


Analysis of other measured characteristics for the Weiliang Audio U9

We prepare automatic analysis with comments of other characteristics and graphs, such as: Follow our news.





Измерения Weiliang Audio U9 проведены Романом Кузнецовым на программно-аппаратном комплексе RAA.

Тест Weiliang Audio U9 проведен как черного ящика, без учета стоимости и престижа. Это главный принцип измерений и разработки тестов в RAA.

Считаю, что важно делать не абсолютную оценку устройства, а совокупную оценку при совместной работе с наушниками и учетом внешних факторов. Это позволяет эффективно раскрывать потенциал всей связки устройств или делать более оптимальный подбор компонентов.




Kuznetsov Roman
Founder of RAA



Known by the nickname romanrex
Аuthor of articles iXBT.com




Weiliang Audio U9 is available in reports and services. You are in a simple report.

Service and suite of tests

Information for entry level users

report for a newbie
(Headphone amplifier)

General recommendations

The automatic selection of the optimal AMP models

Information for all

Comparison of on-line graphs




it is a translation from the Russian language. Original text in Russian page.

You can help us with the correct translation into English.

Select incorrect text and press Ctrl+Enter, forum, facebook and feedback
Thank You!