Language English 


Safety Precautions ▼

Chapter 1 Introduction and features of product ▼

Introduction of product
Features of product


Chapter 2 Nomenclatures and Descriptions ▼

Nomenclatures of front side and Descriptions
Nomenclatures of rear side and Descriptions


Chapter 3 Connection Diagram of Product Application ▼

Chapter 4 Precautions in Use and Charge ▼

Precautions in Use
Precautions in Charge


Chapter 5 Precautions in replacement of OP-AMP & battery ▼

Disassembly of Appliance
Replacement of OP-AMP
Replacement of battery
Assembly of Appliance


Chapter 6 Major Specification and Components ▼

Major Specification


Guide to Service ▼








Safety Precautions ▼


You should read this document before using this product in order to use it safely.










Introduction and features of product ▼


Overview for HUD-mx1
AMP-HP is the Hi-Fi Mobile Headphone Amplifier released to be the best in sound quality, portability and design with embedded battery in tiny and advanced design, and can be used on the move being coupled with various audio portable appliances as like  MP3 Player, Portable CDP, Mobile Phone, iPod or others while you can possibly hear the sufficient volume even with a high impedance headphone above the range of approx. 
300Ω owing to the lift-up of sound quality to Hi-Fi level through the AMP-HP’s unique designing manner of multiple circuit terminal and advanced OP-AMP as well as the substantially increased output. Further, you can hear the best high sound quality in use of it connected with iPod products through iPod Audio Cable as provided in a bundle.


Features of Product

● Replaceable and mounted with MUSES8820, the NJRC’s High Quality Sound Bipolar Input Dual OP-AMP which is of super high sound quality.
● mounted with AD8397, the AnalogDevices’ High Output Current Amplifier of high sound quality/high output.
● Adopted of the unique designing manner to bring about ultra-low noise and sound quality of Hi-Fi level.
● Being mounted with the power circuit for high efficiency/ultra-low noise, it steadily supplies OP-AMP with dual power supply of ±5V up to the full consummation of the battery.
● The unique design provides for the function of Three-way Switch On.
※In order to prevent the battery from unnecessary consuming, power gets on only when all of input/output terminal and power switch get connected and on.
● Adopted of high performance Capacitor as like WIMA, LowESR, Tantal etc..
● It provides convenient portability in the tiny and advanced design. (furnished with portable pouch)
● You can hear the best high sound quality in its connection with iPod product. (furnished with iPod Audio Cable in a bundle)
● A thousand times charge/discharge can be done in maximum, and the high-capacity NiMH battery of 800mAh is embedded.
● Two colors of LED are mounted to display status of charge/discharge. (GREEN ◀ ▶ RED)
● A protection circuit against over-charge/over-discharge is mounted to extend the durability of the battery to the maximum, and therefore a long-time plug-in of the adapter will not lead to an over-charge situation while the battery will automatically become power-off upon Low Voltage being detected.
● In case of automatic power-off owing to detected Low Voltage, the plug-in adapter will lead only to charging work for the sake of protection of appliances which will stay power-off. (Switch ON following the switch-OFF will lead to work.)
● Appliances can be used during the charging work.
 ※As added load to the appliance may cause longer time to charge and more heating, it is recommended to turn the appliance off during the charging work as practicable as possible.







Nomenclatures and Descriptions ▼




① Headphone output(3.5mm stereo mini)

Connect ear-phone or headphone. (recommendable impedance : 16~300Ω)


② Display of Status LED(2 colors LED)
Power ON in its use turns LED on while remaining battery shows itself.
※Color turns from green(full or normal) → scarlet → red(extremely small), and when the Low Voltage comes up as set up, power will automatically become OFF in order to protect the battery. In charging, plug-in of adapter for charge will immediately turn the color of LED from green to red, regardless of power switch ON/OFF, to start the charging work.
※Colors turn as like red(rapid charge) → scarlet → green(charging completed).


③ Power Switch
It functions power ON/OFF, and works only if all of the line input terminal and the headphone output terminal are connected. (Three-way Switch On function mounted)


④ Volume Knob
It regulates the volume of headphone output.
※In view of the features of analogue volume, settings of volume knob are recommended to be above 25%(direction of 9 o’clock) as the minimum.











⑤ Power Supply Terminal
In order to charge the battery embedded, plug in the power-supply-adapter for chare (DC12V~15V) that has been furnished as the basic option.
※In a car, plug-in of cigar-jack (DC12V) will be okay for the charging work.


⑥ Line Input Terminal(3.5mm Stereo Mini)
Connect this with various portable audio appliances as like MP3 Player, Portable CDP, Mobile Phone, iPod or etc.
※You can hear the better high sound quality if iPod products are connected in use of iPod Audio Cable as furnished in a bundle. 

In connecting the cable as furnished, a message of precaution may happen to appear as follows, however it matters nothing wrong with iPod or causes no functional problem either. Please refer to this in use of it.


“This accessory has not been optimized for this iPod. There may occur noises or deterioration of cellular signal by cellular interference.










Connection Diagram of Product Application ▼









Precautions in Use and Charge ▼


Precautions in Use
1. The appliance directly connected with a passive speaker below 16Ω may get easily broken, and therefore be sure to connect it with earphone or headphone above 16Ω.
2. A wetting or a long time abandonment in high humidity may cause the appliance to get broken.
3. Please be cautious that the appliance in a long time abandonment at high temperature above 60℃ may suffer from battery explosion. (Especially in a day of high temperature, don’t leave it unattended inside a car.)
4. Inserting a jack into the input or output terminal in a forced manner may cause the connector to be damaged.
5. Please be cautious that dropping the appliance from a high place may cause a breakdown by impacts. 
6. No free-of-charge A/S will be given to an appliance that are arbitrarily opened, modified or altered.


Precautions in Charge
1. If the surrounding temperature is too high or low, the charging work to the appliance may not go normal. Please have it charged at a room temperature (about 25℃) as practicable as possible.
2. During the charging work, as the appliance will be much loaded and get heated, it is recommended to abstain from using it as practicable as possible.
3. If you mean to use the charged battery for a longer time, keep on using it until the charged battery becomes fully consumed to automatic power-off and don’t pull out the adapter in the charging work until LED turns to green (charge completed). (In other words, a fully charged/discharged battery as repeated is durable for a longer time.)
※ Even when LED turns to green(charge completed), a continued charge for about 4 hours more with the adapter inserted will be adding the charge more about 5~10%. Although the adapter shall be left inserted for a long time, the battery and the appliance will have no strains by the protection circuit as mounted against overcharge. However, for the sake of energy saving, please remove the adapter within about 12 hours.
4. If in charging LED does not turn to red or does not turn to green(charge completed) within about one and half hours or does not turn to green longer after about 3 and half hours,  the appliance or the battery may possibly have some problems, and then please contact our A/S center.







Precautions in replacement of OP-AMP and battery ▼


Disassembly of Appliance
1. At first, remove all jacks connected with the appliance and then switch power off at the front side.
2. Taking care not to damage the case, screw off the two bolts at the rear side panel and remove the rear side panel, and then give a little push to the volume knob at the front side to have the board head out to the backside, and then pull it out slowly.






Replacement of OP-AMP
1. In use of apparatuses for replacing OP-AMP (adaptive tongs, longnoser, pincette etc), pull out completely MUSES8820 that is mounted on socket as a basic option by lifting its front/backside alternately little by little taking care that the PIN of OP-AMP may not get bent seriously.
2. In confirmation in an accurate manner on the direction of replacing OP-AMP to be inserted into the socket emptied by the existing OP-AMP, care must be taken not to have the PIN bent while pressing completely for mounting.


※As the DIP Typed Dual OP-AMP(8PIN), drive   voltage ±5V above will work on it in the most cases.


※Replacement with incompatible OP-AMP or in a wrong direction may cause a serious damage to not only OP-AMP but also the appliance, and any malfunctions derived from these things are entirely considered to be the consumer’s negligence for which no free-of-charge A/S will be served. Please take a special note of this in your mounting work.



Replacement of Battery
1. After taking a note in an accurate manner of the direction of the existing battery and the location of connected cables and connector, remove the existing battery from the connector, and a new battery is to be mounted in a completely identical shape.
2. In replacing the battery that is defective or exhausted, please be sure to take the battery furnished by us for replacement.
※Replacement with other batteries may cause may cause a serious damage to the appliance or the battery, and any malfunctions derived from this thing are entirely considered to be the consumer’s negligence for which no free-of-charge A/S will be served. Please take a special note of this in your replacing work.


Assembly of Appliance
1. Give a slow push to the board after completion of replacement to be matched with the mounting groove firstly from the side of volume knob at the case as removed of the rear side panel until the board and the edge of the case get aligned in a straight line.
※When the front side part reach the front side panel and does not go further, check out the front part in touch and push it while giving a slight move in use of an apparatus properly chosen to match with the groove. 
2. Checking out the mounting work completed, assemble the rear side panel in the reversed order from the disassembly.








Major Specification and Components ▼


Major Specification

Input terminal: 3.5mm stereo mini

Input impedance: 11KΩ
Output terminal: 3.5mm stereo mini
Output impedance: 5Ω
Maximum output: 300mW+300mW @ 32Ω
Recommended headphone impedance: 16~300Ω
OP-AMP in use: MUSES8820(socket type) + AD8397(SMD type)
OPAMP drive power supply: ±5V (dual power supply)
Battery in use: NiMH(800mAh/3.6V pack)
Charging time: about 2 ~ 3 hours
Running time: about 10 hours
Adapter for charge: DC12 ~ 15V/1A
Weight : 134g (including battery)
Dimension(mm) : 60(W) x 80(D) x 20(H)


AMP-HP main body(including battery)
Stereo Mini Cable(as a bundle, White/3.5mm/20cm)
iPod Audio Cable(as a bundle, White/20cm)
Power Adapter for Charge(DC12V~15V)
Portable Pouch







Guide to Service ▼


Warranty period is 1 years from the date of purchase.


● One year period applies to the main body from the purchasing date, while batteries, and adapter are to be exchanged only if found defective at the initial time. Receipts by purchasing products will be the references to confirm the purchasing date, and if not available with receipts for evidence the production date shall apply.


● Receipt of the product tells the date of purchase, and if it is impossible to check the date of purchase from the receipt, the date of purchase is regarded as the same date with that of manufacture.


● Free repair would be accepted only in case of breakdowns during normal use of the product under warranty. Even if the product is under warranty, repair for the product would be charged when the product is damaged by natural disasters(lighting, fire, immersion, and so on), is modified, and is damaged and broken down by user’s careless behaviors and faults.


● If the product breaks down under warranty, you can use mail or delivery service in order to get free repair or you can visit our Customer Service Center yourself for free repair.


● For more inquiries and technical supports for the product, please visit Audinst wep site to use customer board or contact us for consultation.


● Customer Service Center
   #801-1 Jooan Sibeom Gongdan, 17-1, Jooan-Dong, Nam-Gu, Incheon, Korea






본 설명서는 (주)오딘스트가 모든 저작권을 가지므로 내용 중 일부라도 복제하는 것은 금지되어 있습니다. 본 설명서에 기록된 제품의 성능이나 사용방법은 제품의 성능 향상을 위해 예고 없이 변경될 수 있습니다.
● 홈페이지 :
● 고객지원센터 : 인천광역시 남구 주염로 58 (주안동, 주안시범공단공장동 801-1호)



Since only Audinst Inc. holds the copyright, this manual may not be copied or photocopied, in whole or in part.  In order to improve performance, the contents of this manual including the capabilities and the ways to use the product is subject to change without notice.


本書の著作権は Audinst Inc. に帰属します。本書の一部あるいは全部を Audinst Inc. から書面による事前の許諾を得ることなく複写複製(コピー)することを禁じます。本書に表示された製品の機能または規格は、性能向上のために予告なしに変更されることがあります。


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1. 기기의 명칭(모델명) : Amp-HP

2. 제조자/제조국가: (주)오딘스트 / 한국



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FCC Statement

Note: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses and can radiate radio frequency energy and, if not installed and used in acco rdance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures: 


ㆍReorient or relocate the receiving antenna. 
ㆍIncrease the separation between the equipment and receiver. 
ㆍConnect the equipment into an outlet on a circuit different from that to which the receiver is connected. 
ㆍConsult the dealer or an experienced radio/TV technician for help. 


Modifications not expressly approved by the manufacturer could void the user's authority to operated the equipment under FCC rules.