Bluetooth DAC/Headphone Amp
LDAC, aptX-HD, AAC, aptX, SBC
14 Hours Playback
USB DAC/Headphone Amp
USB Audio Class 1.0 (48KHz / 16-bit only)
Works as Preamplifier in vehicles
3.5mm output to car AUX
CAR MODE support(auto power on/off)
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Proprietary DualDrive Technology
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Two AK4375a DAC/HPAMP ICs
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3.5mm Unbalanced output
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2.5mm Balanced output
Proprietary DCT algorithm (on/off option)
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Eliminate noises in digital sound sources
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Enhances 16bit into high resolution 24bit
Built-in Analog Volume control
Noise free even with high-sensitivity earphones
Hands-free call with built-in high sensitive microphone

Companion Android / iOS Application
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Codec selection
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2.5mm / 3.5mm output mode selection
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Battery level status
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Analog & Digital volume control
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10-Band Embedded GEQ control
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AK4375a DAC filter selection/ Oversampling selection
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Proprietary DCT level control
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Cross-feed level control
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Microphone gain control
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Ambient mode On/Off

SPECIFICATIONS
Output Power
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3.5mm Unbalanced: 1.1Vp @ 16Ohm
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2.5mm Balanced: 2.2 Vp @ 16Ohm
Output Impedance
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0.5~1 ohm
SNR* (1KHz, 20KHz AES17)
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3.5mm Unbalanced: 109dB (+2.8dBu)
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2.5mm Balanced: 110dB (+8.8dBu)
Bluetooth Range
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10 meter
THD+N* (1KHz, 20KHz AES17)
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3.5mm Unbalanced: 0.0022%
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2.5mm Balanced: 0.0014%
*SNR and THD+N measured in USB DAC mode
QUICK GUIDE & MANUALS
WHITEPAPERS
APPLICATION NOTES
FIRMWARE UPDATE
Please download the latest version of firmware and refer to the DFU user's guide in the following zip file. During download, a warning message may appear due to some exe files in the zip file, but please disregard and proceed with the download.
Version 2.0.2 (Jan. 2, 2019)
v2.0.2.zip Download
- Changed the press time of power on button to 2 seconds
- Fixed occasional 3.5mm jack detection error
Version 2.0.1 (Nov. 8, 2018)
- Bluetooth 5.0 support
This new firmware based on Bluetooth 5.0 would provide more secure and stable operations though it is nothing to do with sound quality.
- EQ filter precision enhancement; double precision
- Fixed an occasional freezing issue when changing EQ filter presets
- 2.5mm 1x voltage mode output volume level adjustment
3.5mm 1x, 2x current mode and the 2.5mm 1x voltage mode now provide the same output level at a give analog volume.
- Minor bug fixes
Warning
From the firmware v2.0 or later, ES100 supports Bluetooth 5.0 specification. Firmware update with the latest version v2.0 or later is available, but please note that reverting back to v1.4.2 or before is not possible. Once you have it updated with v2.0 or later, DO NOT revert the firmware back to v1.4.2. The device will be bricked.
Version 1.4.2 (Sep. 17, 2018)
- EQ preamp bugfix in v1.4.1
- aptX HD stuttering bugfix in v1.4.0
- Fixed occasional multi-point pairing failure issue
- Optional 2nd device reconnection
- Added USB DAC 44.1KHz support
- Added USB DAC 24-bit support (macOS only)
- Added max. volume limit option
- Added EQ headroom option
- HFP option (for old Android devices)
- Minor bug fix on voice call volume control
- Better antenna sharing with Wi-Fi
WHERE TO BUY
North America - amazon.com
US (*)
CANADA
Europe - amazon.com
UK (*)
ITALY
GERMANY (*)
SPAIN
FRANCE
* Below EU countries can also order from Amazon UK or Amazon GERMANY:
Sweden, Finland, Estonia, Latvia, Lithuania, Denmark, Netherlands, Belgium, Luxembourg, Poland, Czech Republic, Slovakia, Austria, Slovenia,
Hungary, Romania, Bulgaria, Portugal, Malta, Greece, Cyprus and Ireland
Japan - amazon.com
South Korea - online shops
South Asia - online shops
TAILAND BKK Audio

VIETNAM Xuan Vu Audio, David Audio Choice
Asia - online shops
SINGAPORE
HONG KONG
Following countries can also order from Amazon US (non-FBA):
Taiwan, Hong Kong, Thailand, Vietnam, Philippines, Singapore, Malaysia, Indonesia, New Zealand
Customer Support
Please check carefully the manual in this page and the DFU user guide in the firmware zip file first. Afterwards, for technical support, please email to Basically we reply to customer inquires within 2 business days. For other questions including business proposals, please use Contact Us page
Warranty Conditions
1. Radsone warrants EarStudio products for 30 days from the date of purchase against manufacturing defects. In this case, we offer an exchange with an equivalent new product for free. This warranty does not apply to damages caused by accident, abuse, misuse, or modification of the products.
2. Radsone warrants EarStudio products for 1 year from the date of purchase against the damages caused by customers. In this case, the product will be repaired or exchanged with a refurbished product at the customer's expense.