In this article, I’m reviewing the Khadas Tea ultraslim Hi-Fi headphone amplifier. The Tea features an ES9281AC Pro DAC chip, and MQA Renderer and works as both a Bluetooth and wired unit. It supports 32-bit/384kHz, DSD256, LDAC aptX HD and aptX Low Latency. It’s priced at $199.
Disclaimer: This sample was provided by Khadas for an honest review. All observations and opinions here are my own based on my experience with the product.
Khadas Tea
Design
The Khadas Tea’s chassis is made of CNC Machined Aluminum and is available in blue or grey. It’s almost the same size as a credit card, coming in at 95.5mm(l) x 63.8mm(w) x 6.25mm(t-min) / 7.95mm (t-max). It weighs merely 73.5 grams, so it’s super easy to carry around.
The Tea can attach to iPhone 12 or later via a ring of magnets designed especially for the iPhone’s MagSafe feature. However, older iPhone or Android users can buy MagSafe-compatible protective cases that include their own magnetic rings.
You can, of course, just carry the Tea in a pocket or bag. I found it perfect for carrying in my shirt pocket at work. There are a total of 3 buttons on the device for playback controls plus 2 combination button modes.
You can choose whether the 2 buttons on the left side control the volume or next track/previous track function. Personally, I wish they’d just configured it to change the volume with a short press and did next track/previous track with a long press.
I found that on occasion, I would have some accidental button presses when using the Tea, especially when it was in my pocket. I’d like the buttons to have a bit more resistance so they were only pressed when intended.
There are 2 ways to connect the Tea to your phone. You can connect via Bluetooth or by using a USB to lightning or USB to USB cable. Furthermore, you can easily connect the Tea to a laptop or tablet as a USB DAC using the included cables.
Hardware
At the heart of the Khadas Tea is an ES9281AC Pro DAC chip. This is accompanied by a Qualcomm QCC5125 chipset supporting LDAC and aptX HD. The Khadas Tea also has its own microphones built-in so you can use it to make calls, but only when connected via Bluetooth.
The internal 1160mAh battery can provide up to 8 hours of playback. That’s a little less than some of its contemporaries but pretty good considering the slim form factor.
In terms of power output, the Tea pushes 165mW @ 32Ω. That’s a pretty modest number but it’s totally sufficient for the majority of IEMs and efficient headphones. There’s no balanced output, just the 3.5mm single-ended but that’s what most average consumers will be using. I’ll keep my fingers crossed for a future model with a balanced output.
Sound
After admiring the slim chassis of the Tea, it was time to get down to some listening. I tested the Tea with the 7Hz Salnotes Zero, Letshuoer S12 and Meze Audio 99 Classics, figuring that covered a pretty good range of possible use case scenarios.
The Tea had no trouble whatsoever driving my selected transducers to ear bleeding levels. True, they’re all relatively easy to drive but that’s exactly the kind of thing this device was designed for.
In terms of tonality, the Khadas Tea sounds clean and detailed but with a hint of added warmth. It has a musical presentation but one that’s also remarkably transparent. The warmth is more an outcome of having neutral upper mids rather than a boosted bass. This has the effect of keeping the bass tight and crisp while at the same time preserving a cruisy, non-fatiguing tonality.
I was really impressed with the staging and the Tea’s instrument spacing is a treat for the ears. With a resolving IEM like the Letshuoer S12, the sound is resolving and all the micro-details are present. The bass is controlled and layered plus it has good sub-bass extension.
Switching over to the Salnotes Zero, I was amazed at the quality of the audio I was hearing from this affordable little duo. Bass notes are fast but full-bodied. Instruments in the midrange have a natural tone and ideal note weight. Vocals are rich, articulate and full of nuance. The treble is breathy but effortless and has an accurate timbre.
Using the Tea with a wired connection yields the best results but the quality of the Bluetooth audio is superb. Using my Sony DAP with LDAC sounded the best to my ears but with my iPhone and AAC, the results were also impressive.
Verdict
The Khadas Tea gives us familiar tech in a new form factor. At first, I wasn’t sure how I’d like the slim chassis but it turned out to be ideal, especially for shirt pockets. It works great with the MagSafe magnets too, although I had to borrow my wife’s phone to test that.
The Tea’s spacious, firm sound is better than I expected. I’m not sure if it’s the tonality or the staging I enjoy the most but I enjoy it a lot. While it’s designed primarily for iPhones, there’s no reason you can’t enjoy it with an Android phone either: you can easily slip it into a pocket or get yourself a MagSafe-compatible phone case. Either way, the Khadas Tea is one very cool device.
Specifications
- Output Impedance
- < 0.3Ω
- THD+N, 1KHz, 300Ω 0.000355% (-109dB)
- THD+N, 1KHz, 150Ω 0.000355% (-109dB)
- THD+N, 1KHz, 32Ω 0.000447% (-107dB)
- THD+N, 1KHz, 16Ω 0.000708% (-103dB)
- Noise < 3.2uVrms
- SNR, High-gain Mode 116dB
- SNR, Low-gain Mode 112dB
- DNR, High-gain Mode 115dB
- DNR, Low-gain Mode 111dB
- Max Output @300Ω 20.8mW (2.5Vrms)
- Max Output @150Ω 42.7mW (2.5Vrms)
- Max Output @32Ω 165mW (2.3Vrms)
- Max Output @16Ω 130mW (1.44Vrms)
- Crosstalk, 600Ω > 113dB
- Crosstalk, 32Ω > 70dB
- Frequency Response, 20Hz~20KHz ±0.05dB
- Sampling Rate
- USB: up to 32bit 384KHz @PCM, or DSD 256 (Native)
- Bluetooth: up to 24bit 96KHz
- Audio Formats
- USB: MQA(Renderer), AAC, FLAC, APE, WMA, WAV, OGG, MP3 …
- Bluetooth: LDAC, aptX HD
- Chip
- USB DAC: ESS ES9281ACPRO
- Bluetooth: Qualcomm QCC5125
- Amplifier RT6863D (Buffer Stage)
- Apple MFi
- MFi 3.0
- Power and Battery
- Rechargeable Lithium Polymer, 1160mAh
- Up to 8 hours playback
- Rated Voltage: DC 5V
- Size
- 95.5mm(l) x 63.8mm(w) x 6.25mm(t-min) / 7.95mm (t-max)
- Weight
- 73.5 grams