+86-13790758128  service@jhhearingaids.com

JH-338 Manual

Included in delivery #

2 x hearing Amplifier (Sound Amplifier)
1 x Plastic box 1 x Clearing set
1 x USB Dock 1 x Storage Bag
1 x Adapter 1 x Instruction manual

1. Intended Use #

The sound amplifier is only to be used to help people to hear better.
The device is only intended for the purpose described in these instructions for use.
The manufacturer is not liable for damage resulting from improper or careless use.
The sound amplifier is an amplifying device and is not a therapeutic medical product.

2. Signs and symbols #

The following symbols appear in these instructions:
Waring instruction indicating a risk of injury or damage to health.
Safety not indicating possible damage to the unit /accessory.
Note on important information

3. Getting to know your instrument #

The sound amplifier is a device to help people hear better. It does this by amplifying sound and then transmitting these to the ear. The sound amplifier can neither prevent alleviate organically caused hearing loss.
The sound amplifier offers you a variety of applications. Regardless of whether you want to watch a film. chat with friends of just feel like listening to the sounds of nature in the woods. the sound amplifier helps you to hear sounds louder and more clearly.

4. Warnings and Safety notes #

Do NOT use the sound amplifier if you are suffering from an inflammation of the middle ear or ear canal.
Do NOT use the sound amplifier at maximum volume over a long period of time. This could damage your hearing.
If you feel unwell or experience pain when wearing the sound amplifier, stop using it immediately and contact your doctor.
This device is not intended for use by people (include children) with restricted physical, sensory or mental skills or a lack of experience and /or a lack of knowledge unless they are suervised by a person who has responsibility for their safety or the receive instructions from this person on how to use the device. Children should be supervised around the device to ensure they do not play with it.
Do NOT use the sound amplifier in potentially explosive and hazardous environments.
Keep the sound amplifier , the accessories and the batteries away from children, as there is a risk of choking.
Keep batteries out of the reach of children. Children can put batteries in their mouths and swallow them. This may severely damage their health. I such cases, seek medical assistance immediately!
Mormal batteries must not be charged, Heated or thrown into an open fire (risk of explosion!)
Leaking or damagend batteries may burn the skin therefore use sutable protective gloves if this is the case.
If your have any doubts, do not use a damaged soud amplifier; contact your retailer or specified Customer Services address.
Switch the device off immediately if it is faulty or not working properly.
Do not attempt to open and /or repair the sound amplifier yourself. Repairs may only be carried our by Customer Services or authoriesd retailers. Failure to comply will result in voiding of warranty.


Do NOT wear the sound amplifer while bathing, showering or swimming.
Do NOT wear the sound amplifer while applying cosmetics (e.g. make-up, hairspray, perfume or sum cream).
Do NOT wear the sound amplifer while undergoing shortwave therapy or medical treatments that are subject ot strong radio frequency or magnetic fields.
Do NOT wear the sound amplifier in the vicinity of strong eletromagentic fields or X-rays.
Protect the device from impacts, humidity , dirt marked temperature fluctuations and direct sunlight.
Never dry your sound amplifier in the microwave.
Service your sound amplifier at regular intervals. Make sure there are not foreign objects in between the earplug and headphones , as this coud impair the sound.

5. Unit Description #

1. Microphone
2. Volume cont5rol
3. On/Off switch (“N”=On, “O”=Off)
4. Charging hole
5. Headphones
5 Earplug

6. Initial use and operation #

Remove the sound amplifier from the packageing and check that the device and all accessories are included and not damaged.

1. Choosing the correct earplug size on your sound amplifier to fit with your ear, and avoid external noise interference.
2. Turn the volume control to the lowest setting.
3. Bring the sound amplifier up to your ear. Slowly insert the earplug into your ear canal applying on the force. Make sure not to insert the earplug too deeply into the ear canal, If the earplug is not properly in place or feels uncomfortable, Try a different earplug.
4 Move the On/Off switch to “N” to switch on the Sound amplifier. Use the volume control to adjust the volume to the desired level so that you can hear sound clearly and distinctly.
Make sure the volume control is initially set to the lowest setting before operating the sound amplifier.
If you hear a lisght whistling sound when wearing the sound amplifier, check that your earplug is fitted properly in your ear. If it is not snug enough , use a different earplug.
If the sound amplifer in low sound amplifying, please complete the charging first.


1. Turn off the sound amplifier.
2. Push the bottom the charging hole of the sound amplifier into the USB dock, ensure it is click into the USB dock place. (Two sound amplifier can be charing at the same time)
3. Connect the USB dock to either a computer with a USB port or connect with Adapter.
4. A red light will turn on to show the sound amplifier is charging.
5. The red light will turn to green once the charge is complete. It takes about 7 hours to charge.
Turn off the sound amplifier before the charge.
Don’t use up the power of the sound amplifier before recharge.

8. Maintenance and cleaning #

Remove the battry from the device before cleaning .
Clean the sound amplifier and the earplugs with a clean, dry cloth afrer each use. If they are very dirty, you can also moisten the cloth with a mild soapy solution. Never use abrasive corrosive or solvent-based cleaning products.
Allow the sound amplifer to dry fully after cleaning . Store the sound amplifier in a safe, dry, and clean place.
Under no circumstances should you hold the sound amplifier underwater, as this can cause the liquid to enter and damage the sound amplifier.
If you do not intend to use the sound amplifier for longer periods, remove the battery from the device to prevent possible leaking.


No sounds can be heard from the sound amplifier
Possible causes
Soudn amplifier is not switched on
Power used up.
The microphone is dirty.
The sound amplifier is damaged.

The soudn amplifier is very quiet.
Possible causes
The volume setting on the sound amplifer is too low.
Power is too low
Earplug is dirty
Microphone is dirty.


Sound Output (SSPL): 128 +- 3dB
Sound Gain (SSPL)@50dB : 95 +-3dB
Noise : EIN < 26dB
Frequency Range :400Hz to 4.2 Khz
Working Current: 3.5mA
Harmonic Wave Distortion (THD) : Volume reference
500 Hz : <=3%
800 Hz: <=5%
1600 Hz:<=1%
Rechargeable Battery: NI-MH
Recharge Time : 7 hours
Working Time : 16 hours
Dimesion: 40mm x13mm x10mm
Weight: 4.3g
Operating Temperature: 0C ~ 40C
Storage Temperature: -10C – 55 C
Humidity : <= 90RG

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