This is a report for professionals with a suite of test of headphone amplifier.
You can see a simple report for "dummies" with explanations of the main characteristics for HiFiMan EF 400 Single-ended Out

A suite of tests for a headphone amplifier can be applied to just a universal output without a formal presence of an amplifier, if in this mode you can connect headphones to this output. Based on the results of the tests, you can understand the real picture, is the output powerful enough or not, with the initial data on the circuitry as a "black box".

Line-out, differences from the output for headphones and speakers

Advantages and disadvantages of balanced amplifiers

Test report - general data HiFiMan EF 400 (as headphone amplifier)

Frequency response, Impedance and Frequency response with standard headphones

Voltage levels from the load at the output of the amplifier

Average value of impedance band in 40 Hz - 15 kHz	4.9	ohm
Voltage: Linear Mode / Maximum or before clipping level	17.2/17.2	dBV
	7.2/7.2	V_RMS
Current: Linear Mode / Maximum or before clipping level	43.8/48.7	dB(mA)
	154.1/270.9	mA

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Frequency response HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Range

Channel:	Left	Right
Variation in frequency response in band from 40 Hz - 15 kHz	-0.2, +0.0	-0.2, +0.0	dB

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

On the frequency response comparison page, there is an export option and additional tools for adjusting the frequency response

Impedance HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Channel:	Left	Right
Impedance average in band from 40 Hz - 15 kHz	4.9	4.9	ohm
The minimum value in band from 40 Hz - 15 kHz	4.9	4.9	ohm
The maximum value in band from 40 Hz - 15 kHz	4.9	4.9	ohm

Comparison of basic characteristics AMPs

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Crosstalk HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Range

Load

Channel:	Left	Right
Crosstalk @ 1 kHz @ 15.8 ohm	-55.7	-55.8	dB
Crosstalk @ 1 kHz @ 24.5 ohm	-58.6	-58.7	dB
Crosstalk @ 1 kHz @ 30.5 ohm	-60.5	-60.5	dB
Crosstalk @ 1 kHz @ 62.4 ohm	-66.0	-66.2	dB
Crosstalk @ 1 kHz @ 100.0 ohm	-70.0	-70.0	dB
Crosstalk @ 1 kHz @ 198.9 ohm	-75.8	-75.8	dB
Crosstalk @ 1 kHz @ 300.0 ohm	-79.2	-79.1	dB
Crosstalk @ 1 kHz @ 763.0 ohm	-87.2	-86.6	dB
Crosstalk @ 1 kHz @ Not loaded	-115.6	-100.3	dB

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Crosstalk Phase HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Load

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Frequency response HiFiMan EF 400 Single-ended Out with resistive load

Graphics setting view

Channel

Range

Frequency response of amplifier with resistive load @ 40 Hz - 15 kHz

Channel:	Left	Right
TEST 16 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB
TEST 32 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB
TEST 64 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB
TEST 126 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB
TEST 256 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB
TEST 512 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

On the frequency response comparison page, there is an export option and additional tools for adjusting the frequency response

Frequency response HiFiMan EF 400 Single-ended Out loaded dynamic headphone type

Graphics setting view

Channel

Range

Frequency response of amplifier loaded dynamic headphone type @ 40 Hz - 15 kHz

Channel:	Left	Right
TEST 10000 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB
Grado GH4 Limited Edition + HiFiMan EF 400 Single-ended Out	0.8	0.8	dB

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

On the frequency response comparison page, there is an export option and additional tools for adjusting the frequency response

Frequency response HiFiMan EF 400 Single-ended Out loaded type balance armature headphone type

Graphics setting view

Channel

Range

Frequency response of amplifier loaded type balance armature headphone type @ 40 Hz - 15 kHz

Channel:	Left	Right
TEST 10000 ? + HiFiMan EF 400 Single-ended Out	0.0	0.0	dB
Campfire Audio Andromeda + HiFiMan EF 400 Single-ended Out	5.8	5.8	dB
Fearless Audio S8F Freedom + HiFiMan EF 400 Single-ended Out	4.7	4.3	dB

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

On the frequency response comparison page, there is an export option and additional tools for adjusting the frequency response

THD vs load vs output voltage HiFiMan EF 400 Single-ended Out

Graphics setting view

Channel

Load

Harmonic, number

Graphics setting view

Channel

Load

Harmonic, number

Graphics setting view

Channel

Load

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Maximum voltage output level vs load HiFiMan EF 400 Single-ended Out

Graphics setting view

Type of chart

RAW coordinates

Power characteristics of the	Voltage		Current
	dBV	V_RMS	dB(mA)	mA
Equivalent class A	17.2	7.2	43.8	154.1
Equivalent class AB	17.2	7.2	47.8	245.8
Equivalent class B	17.2	7.2	48.7	270.9
Maximum mode	17.2	7.2	48.7	270.9

Volume Control Type	Analog
Optimal range of volume control	36.0	dB

Comparison HiFiMan EF 400 Single-ended Out and another amplifiers by loudness (Volume Level)

Main characteristics of the HiFiMan EF 400 Single-ended Out

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Maximum voltage output level vs load HiFiMan EF 400 Single-ended Out

Graphics setting view

Type of chart

RAW coordinates

Maximum Amplifier Voltage Level

Load	Pure or equal class A		Optimal or equal class AB		Hard or equal class B		Max, before clipping
	dBV	V_RMS	dBV	V_RMS	dBV	V_RMS	dBV	V_RMS
15.8 ohm	8.6	2.7	12.6	2.7	12.6	2.7	12.6	2.7
24.5 ohm	11.7	3.8	14.7	3.8	14.7	3.8	14.7	3.8
30.5 ohm	12.3	4.1	15.3	4.1	15.3	4.1	15.3	4.1
62.4 ohm	16.2	6.4	16.2	6.4	16.2	6.4	16.2	6.4
100 ohm	15.8	6.1	16.8	6.1	16.8	6.1	16.8	6.1
198.9 ohm	16.0	6.3	17.0	6.3	17.0	6.3	17.0	6.3
300 ohm	17.0	7.1	17.0	7.1	17.0	7.1	17.0	7.1
763 ohm	17.1	7.2	17.1	7.2	17.1	7.2	17.1	7.2
Not loaded	17.2	7.2	17.2	7.2	17.2	7.2	17.2	7.2

Maximum level of amplifier current

Load	Pure or equal class A		Optimal or equal class AB		Hard or equal class B		Max, before clipping
	dB(mA)	mA	dB(mA)	mA	dB(mA)	mA	dB(mA)	mA
15.8 ohm	44.7	171.0	48.7	270.9	48.7	270.9	48.7	270.9
24.5 ohm	43.9	156.4	46.9	220.8	46.9	220.8	46.9	220.8
30.5 ohm	42.6	135.1	45.6	190.8	45.6	190.8	45.6	190.8
62.4 ohm	40.3	103.0	40.3	103.0	40.3	103.0	40.3	103.0
100 ohm	35.8	61.4	36.8	68.8	36.8	68.8	36.8	68.8
198.9 ohm	30.0	31.6	31.0	35.5	31.0	35.5	31.0	35.5
300 ohm	27.5	23.7	27.5	23.7	27.5	23.7	27.5	23.7
763 ohm	19.5	9.4	19.5	9.4	19.5	9.4	19.5	9.4

Power

Load	Pure or equal class A		Optimal or equal class AB		Hard or equal class B		Max, before clipping
	dBm	mW	dBm	mW	dBm	mW	dBm	mW
15.8 ohm	26.6	461.9	30.6	1159.3	30.6	1159.3	30.6	1159.3
24.5 ohm	27.8	598.9	30.8	1194.4	30.8	1194.4	30.8	1194.4
30.5 ohm	27.5	556.8	30.5	1110.3	30.5	1110.3	30.5	1110.3
62.4 ohm	28.2	662.0	28.2	662.0	28.2	662.0	28.2	662.0
100 ohm	25.8	376.9	26.8	473.3	26.8	473.3	26.8	473.3
198.9 ohm	23.0	198.7	24.0	250.0	24.0	250.0	24.0	250.0
300 ohm	22.3	168.5	22.3	168.5	22.3	168.5	22.3	168.5
763 ohm	18.3	67.6	18.3	67.6	18.3	67.6	18.3	67.6

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Spectrum of Total Harmonic Distortion vs Level HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Level

Range

Graphics setting view

Channel

Level

Range

Graphics setting view

Channel

Shift

dBm

Range

Graphics setting view

Channel

Shift

dBV

Range

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Spectrum of Multitone Distortion vs Level vs Load HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Level

Range

Graphics setting view

Channel

Level

Range

Graphics setting view

Channel

Shift

dBm

Range

Graphics setting view

Channel

Shift

dBV

Range

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Spectrum of IMD SMPTE vs Level HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Level

Range

Range

Graphics setting view

Channel

Level

Range

Range

Graphics setting view

Channel

Shift

Range

dBm

Range

Graphics setting view

Channel

Shift

Range

dBV

Range

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

Spectrum of IMD CCIF vs Level HiFiMan EF 400 Single-ended Out (as headphone amplifier)

Graphics setting view

Channel

Level

Range

Graphics setting view

Channel

Level

Range

Graphics setting view

Channel

Shift

dBm

Range

Graphics setting view

Channel

Shift

dBV

Range

Brief information

Clicking on the graph will take you to the comparison page of different models with advanced graph display settings.

More detailed

Measurements of HiFiMan EF 400 Single-ended Out were carried out by Roman Kuznetsov on the hardware-software complex RAA.

The HiFiMan EF 400 Single-ended Out test was conducted as a black box test, without regard to cost and prestige. This is the basic principle for making measurements, measurement reports and developing tests in RAA.

I believe that it is important to do not make an absolute assessment of the device, but an aggregate assessment when working together with a headphones and taking into account external factors. This allows you to effectively reveal the potential of the entire set of devices or to make a more optimal choice of components.

Kuznetsov Roman
Founder of RAA

Known by the nickname romanrex
Аuthor of articles iXBT.com

Information for Authors. You can freely use the graphics in your articles with a link to us.

HiFiMan EF 400 is available in reports and services. You are in a professional report.

Information for entry level users

reports for a newbie (Headphone amplifier)

The automatic selection of the optimal AMP models

Information for all

Versus of characteristics

Information for professionals

reports for a pro (Headphone amplifier)

reports for a pro (DAC Line Out)

OS Mode

Comparison of on-line graphs

Quick jump to the schedule in this report: Single-ended Out

Original text in Russian page. Translation page is not yet ready

You can help with translation via the: facebook and feedback.

Comments

Комментарий из чата telegram RAA от И л ь я B e s k
Изображения, медиа и смайлы доступны в исходном чате.
2023-04-14 18:03:50

Комментарий к профессиональному отчету HiFiMan EF 400 OS Mode

Потянет ли их Hifiman EF-400..?

Reply Edit

Комментарий из чата telegram RAA от Alex
Изображения, медиа и смайлы доступны в исходном чате.
2023-04-14 18:41:24

Комментарий к профессиональному отчету HiFiMan EF 400 OS Mode

судя по связке усилитель-наушники потянет. График для 105дцб

Reply Edit

Комментарий из чата telegram RAA от romanrex
Изображения, медиа и смайлы доступны в исходном чате.
2023-04-15 10:25:24

Комментарий к профессиональному отчету HiFiMan EF 400 OS Mode

Лучше всего определить свой референсный уровень громкости, тогда точно для себя будет ответ.
https://reference-audio-analyzer.pro/faq-ref-spl.php

Уровни громкости в связке можно посмотреть так
http://reference-audio-analyzer.pro/param21.php?&idhp0=4458&idamp0=4204&vol0=0&idhp1=4458&idamp1=4205&vol1=0&ls=2&cl0=%23BB0303&cl2_0=%23BB0303&cl1=%23094A78&cl2_1=%23094A78&stand0=HDM-X&stand1=HDM-X&style0=0&style1=0&mh221=221&ma74=74

Reply Edit

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