General results
- Output Impedance: 13.44 ohm
Characteristics for the high quality mode
- Power and voltage for 32 ohm : 0.03 mW/ / -29.9 dBV
- Power and voltage for 300 ohm : 0.30 mW/ / -10.5 dBV
- Recommended Headphones
- In-Ear or Tablet headphones: No recommendation, Amp is too quiet
- Over-ear headphones: No recommendation, Amp is too quiet
Maximum
- Power and voltage for 32 ohm : 0.03 mW/ / -29.9 dBV
- Power and voltage for 300 ohm : 0.30 mW/ / -10.5 dBV
- Recommended Headphones
- In-Ear or Tablet headphones: No recommendation, Amp is too quiet
- Over-ear headphones: No recommendation, Amp is too quiet
About quality modes
We make borders for the maximum characteristics for current and voltage by sound signal reproduction quality levels. In general, when the volume level is increased, the sound quality of the amplifier degrade. Approximately as a car above a certain speed becomes less manageable. High-quality mode is a mode in which it is considered that the amplifier works as clear as possible without distortion and corresponds to the equivalent class A 
. As a car at speed with excellent manageability.
The maximum mode is a mode in which it is considered that the amplifier operates without an audible wheeze from overloading (clipping) or this is the maximum position of the volume control and a higher volume level is not possible. As if the car has already reached a speed above which manageability is lost or the car can not reach a higher speed.
Recommended headphone impedances are determined for in-headphones with a sensitivity of 112 dB / mW SPL and full-sized 99 dB / mW SPL while providing a maximum sound pressure level of 116 dB SPL (average sound pressure level will be 9 dB less, since the music track is usually contains not only loud parts, but also quiet ones).
. As a car at speed with excellent manageability.
The maximum mode
is a mode in which it is considered that the amplifier operates without an audible wheeze from overloading (clipping) or this is the maximum position of the volume control and a higher volume level is not possible. As if the car has already reached a speed above which manageability is lost or the car can not reach a higher speed.
Recommended headphone impedances are determined for in-headphones with a sensitivity of 112 dB / mW SPL and full-sized 99 dB / mW SPL while providing a maximum sound pressure level of 116 dB SPL (average sound pressure level will be 9 dB less, since the music track is usually contains not only loud parts, but also quiet ones).
About a simple report
This is a simply report for dummies who are poorly versed in the characteristics of the amp part of various devices and don’t understand specialized graphs.
Information in this report is presented in simple and clear form. Data interpretation were made as simple as possible and accordingly hadn’t much subtleties and nuances. Simple report is sufficient for a general assessment of the device. For more complete and accurate assessment you should read professional report.
All characteristics are accompanied by detailed explanations to enable reader to gradually understand dependencies between the characteristics. The aim is to give you ability to understand a more complex professional report.
For example, when choose new computer video card, many persons do not understand the set of tables with the final data of the test packages of video cards. 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 and consciously, then the reader gradually deepens into complex tables, mastering information from simple to complex.
We made the separation of reports into "simple" and "complex", where a simple report with explanations will allow you to gradually understand and professional report.
Information in this report is presented in simple and clear form. Data interpretation were made as simple as possible and accordingly hadn’t much subtleties and nuances. Simple report is sufficient for a general assessment of the device. For more complete and accurate assessment you should read professional report.
All characteristics are accompanied by detailed explanations to enable reader to gradually understand dependencies between the characteristics. The aim is to give you ability to understand a more complex professional report.
For example, when choose new computer video card, many persons do not understand the set of tables with the final data of the test packages of video cards. 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 and consciously, then the reader gradually deepens into complex tables, mastering information from simple to complex.
We made the separation of reports into "simple" and "complex", where a simple report with explanations will allow you to gradually understand and professional report.
Description of the characteristics and recommendations 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 Sony Ericsson W995 3,5
The main "universal" characteristics of the amplifier are maximum voltage, maximum current and output impedance maximum voltage, maximum current and output resistance according to the universal block diagram .
The values of current and voltage can be divided by quality thresholds.
In general, when the volume increases, the sound quality of the amplifier deteriorates. It's like a car with a certain speed becomes less manageable. In this report, we consider two thresholds.
- The linear mode of the transfer characteristic is of high quality (like the excellent handling of the car at low speed).
- The maximum mode is the limiting characteristics, where it is either impossible to set the volume level higher, or the amplifier wheezes at a higher volume (like a car that cannot reach a higher speed or loses control above a certain speed).
Voltage
- The maximum voltage level without load is 0.00 dBV.
- The maximum voltage level in linear mode without load is 0.00 dBV.
) and the sensitivity of the headphones to voltage.
If the required voltage level from the amplifier for a comfortable volume level
is below the threshold value of the linear mode, then the sound is as clean and high-quality as possible. If this threshold is exceeded, the sound quality decreases . When the maximum voltage level is exceeded, strong distortions occur in the form of "wheezing".
Current
- The maximum current level is 0.00 dB(mA)
- The current level in linear mode is 0.00 dB(mA).
If the current consumption of headphones at a comfortable volume
is higher than the threshold value for linear mode, then the sound is as clean as possible. If this threshold is exceeded, the sound quality decreases . When the maximum current level is exceeded, strong distortions occur in the form of "wheezing".
Output Impedance
- The output impedance of the amplifier is 13.44 ohm.
When the impedance of the headphones is uneven, the voltage drop occurs unevenly and the final frequency response of the headphones changes
. Accordingly, the higher the resistance of the amplifier, the changes in frequency response become more noticeable for headphones with uneven impedance.
The resistance of the amplifier affects the mutual penetration of channels in the opposite phase at the Single-ended output. The lower the resistance of the amplifier and headphones, the more channels are mixed and the more the headphone cable affects channel mixing
.
Detailed analysis of technical characteristics
Analyse of the output impedance of the Sony Ericsson W995 for 3,5Mod
The Sony Ericsson W995 3,5 has an output impedance of 13.44 ohms.This is the average resistance. With this resistance, the voltage reduction under low-impedance headphones is relatively small.
For low-impedance headphones, this gives an optimal ratio between the volume margin and the reduction of background noise.
If the voltage on headphones with a impedance of 600 ohms is 0.00 dBV, then at 16 ohms it decreases by 0.00 dB to 0.00 dBV. You can listen
to this difference yourself.
Analysis of voltage and current of the Sony Ericsson W995 3,5 with graph
V = SPL - Sensitivity + Peak factor - Output voltage + Correction for external circumstances
where:
One of the main tasks of identifying the compatibility of headphones with a specific amplifier is to find out whether the amplifier can give the optimal voltage level that is responsible for the final volume. This section describes in more detail how the voltage graph is constructed from the initial parameters of the amplifier
: voltage, current and impedance of the amplifier.
Based on the values of the maximum voltage
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, 65, 125, 300 and 600 ohms.
Since we perceive the difference in volume not linearly, but in multiples, not only the final sound pressure is expressed in dB SPL instead of Pa (Pascal). Similarly, the voltage instead of VRMS is expressed in dBV decibels
. This allows you to compare the volume immediately in decibels , which many are familiar with equalizers and volume adjustments. The graph on the left shows the voltage values in VRMS.
The graph grid has a step of 6 dB, which is a multiple of doubling the voltage. A person can subjectively distinguish a difference in volume of 1 dB. The relationship between the sound pressure in dB SPL and the voltage in dBV is direct.
Since we are interested not only in how loud the amplifier can work, but also in what volume range we can get good sound quality, we make an assessment based on voltage and current data for the linear mode of the equivalent class A
.
The blue color shows the voltage level for the linear section of the transmission characteristic with headphones connected without current limitation.
Each value of the headphone resistance requires a certain level of current at the output voltage of the amplifier. The orange color shows the voltage level for a linear section with a current limit only.
From two levels of constraint options, green columns are obtained.
The lower bound for the green columns in the form of a minimum voltage value is determined by the range of optimal volume control from the maximum level. This is the desired voltage range, which is optimal for the amplifier.
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.
from the maximum level. This is the desired voltage range, which is optimal for the amplifier.
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.
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. But, usually the adjustment step in the low volume area is large.
To obtain maximum quality, discrete regulators (stepped volume control) are used. But, usually the adjustment step in the low volume area is large.
It is best to use headphones with such sensitivity that the comfortable volume level is within the voltage range from the optimal range with volume control.
Thus, the lower level is limited by the recommended volume control range, and the upper level is calculated based on current and voltage limitations in the highest quality mode for this device without harmonics of higher orders.
For headphones, you can calculate the required voltage based on their sensitivity, environmental conditions and the required final volume.
If the required voltage value is under the green area of the columns, then the headphones are overly sensitive for Sony Ericsson W995 3,5 and to set the optimal volume, you will need to lower the level by more than 36 dB from the maximum.
If the required voltage value is above the green area of the columns, then we will have headphones with insufficient sensitivity and/or insufficient voltage level of the amplifier in the highest quality mode.
Если значение будет выше зеленой области столбцов, но не превысит серую область, то необходимую громкость наушники дадут, но звучание будет менее качественное, т.к. усилитель будет работать уже в менее качественных режимах усиления.
If the value exceeds the maximum (green with gray) level, then the necessary volume either cannot be set, or the wheezing from clipping will be clearly audible.
that the comfortable volume level is within the voltage range from the optimal range with volume control.
Thus, the lower level is limited by the recommended volume control range, and the upper level is calculated based on current and voltage limitations in the highest quality mode for this device without harmonics of higher orders.
For headphones, you can calculate the required voltage based on their sensitivity, environmental conditions and the required final volume.
If the required voltage value is under the green area of the columns, then the headphones are overly sensitive for Sony Ericsson W995 3,5 and to set the optimal volume, you will need to lower the level by more than 36 dB from the maximum.
If the required voltage value is above the green area of the columns, then we will have headphones with insufficient sensitivity and/or insufficient voltage level of the amplifier in the highest quality mode.
Если значение будет выше зеленой области столбцов, но не превысит серую область, то необходимую громкость наушники дадут, но звучание будет менее качественное, т.к. усилитель будет работать уже в менее качественных режимах усиления.
If the value exceeds the maximum (green with gray) level, then the necessary volume either cannot be set, or the wheezing from clipping will be clearly audible.
- 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, the estimates are calculated in the table in the form of stars, where the estimate shows how much the value of the required voltage for headphones is comparable to the green area of the columns.
The analysis for specific headphones can be viewed
separately by selecting the headphone models on the professional chart.
The analysis for specific headphones can be viewed
separately by selecting the headphone models on the professional chart.
Analysis of use Sony Ericsson W995 3,5 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.
