General Information

Colorfly BT-C1
Portable Bluetooth Decoding Headphone Amplifier



BT-C1 adopts ESS9318 professional DAC audio converter. The chip supports PCM 32bit 384kHz and DSD256 decoding, SNR is up to125dB, THD is -113dB, integrated decoding and amplifying function, can greatly enhance the audio playback effect of mobile phones.


  • Model: BT-C1
  • Sample rate: 32bit/192kHz
  • Output power: 32mW (32Ω load 1KHz/THD+N<1%)
  • Bluetooth version: 5.0
  • Distortion: <0.05%
  • DAC chip: ESS 9318
  • Signal to noise ratio: ≥125dB
  • Headphone jack: 3.5mm
  • Bluetooth audio support formats: SBC, MP3, AAC, APTX, APTXLL
  • Bluetooth aptX: support
  • Battery capacity: 270mAh
  • Charging time: 1.5 hours
  • Life: ≥ 6 hours
  • Size: 42mm*42mm*12mm


  • Colorfly BT-C1
  • USB Charge Cable
  • Lanyard

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Latest reviews


500+ Head-Fier
Pros: physical controls, neutral sound, good bass and treble extension
Cons: no ASIO driver, requires external amp
As the modern trend continues to exclude 3.5mm audio outputs from recently released popular smartphones, more and more audio brands present their pocket USB/wireless DACs to bring back the ability to use standard headphones and IEMs. Of course, external USB DACs for smartphones existed long before Apple has decided to get rid of analog output (leading others to do the same) but the main purpose was to maximize audio quality whilst physical characteristics such as dimensions and weight were not so important for a «true audiophile». The paradigm has changed. Current products in this niche would offer very small formfactor, no internal battery and low weight, representing kind of «clever» USB to 3.5mm adaptors rather than sophisticated DAC/AMP.

Today, we would review Colorfly BT-C1 — Bluetooth/USB digital to analog converter / amplifier which stands somewhere inbetween the regular external battery powered USB DACs and current small digital to analog adaptors.


We think that there is no need to make the presentation of famous Colorfly brand — a brand that is well-known for high quality DAPs like C4Pro, C3, C10, C200. The only fact that is worth to mention is that Colorfly wasn’t very active for the past year and kept quiet for a long time until they’ve released BT-C1 DAC&AMP. Anyway, let’s move on and examine this device.

Colorfly BT-C1 technical specifications:
  • Sample rates: up to 32bit/384kHz, DSD256
  • Output power: 32mW (32Ω load 1kHz / THD+N<1%)
  • Bluetooth version: 5.0, (2 devices)
  • Distortions: <0.05%
  • THD: -113dB
  • DAC chip: ESS9318
  • SNR: ≥125dB
  • Headphone jack: 3.5mm
  • Bluetooth audio formats: SBC, AptX, AptX_LL
  • Ports: microUSB
  • Battery: 270mAh
  • Charging time: 1.5 hours
  • Music play: ≥ 6 hours
  • Dimensions: 42mm*42mm*12mm
  • Weight: ~27g

Packaging, materials and design:

BT-C1 comes in a small black box with full product description at the back. Folding facing part of the box contains short button operation manual underneath.

Box includes only few items:
  • BT-C1 DAC
  • lanyard
  • microUSB to USB cable

We hoped to see more cables inside to get this device up and running with different sources straight out of the box. No luck. We had to find such adaptors as microUSB -> microUSB, microUSB -> microUSB type-C to be able to connect to our Xiaomi smartphones (Redmi Note 4X and Note 5).


BT-C1 DAC is very small device, made of two aluminum parts while the bottom part is covered with glass that has anti-fingerprint coating.


BT-C1 features very handy physical controls:
  • ON|OFF / PLAY|PAUSE button
  • NEXT Track button
  • PREVIOUS Track button
those are located on the left side edge


  • Volume control wheel
which is located at top

Here is the chematics of all control elements and their functions:


There are additional shell openings for multi-color state LED (upward facing side near the volume wheel) and microphone (next to button section). 3.5mm audio output and microUSB port are located at the bottom edge. Volume wheel feels tight and clicks with the descrete adjustments.

LED would change its color depending of the current state:


Build quality is decent. This device is very small and lightweight despite the built in battery. The only concern so far is the close location of audio output and microUSB port — space is enough to connect any headphones but looks weird and might be not so confrotable to carry around in the pocket.


Usage scenarios:

We think that this device was intended for the next usage scenarios:

1. Adding 3.5mm audio output to a smartphone|laptop|tablet if there isn’t one

If there is not 3.5mm output and you have good headphones with 3.5mm jack — BT-C1 would be a good choice in terms of sound quality characteristics.

2. Upgrading sound quality of a smartphone|laptop|tablet not regarding whether there is native 3.5mm audio output or not.

This implies that you are not satisfied with the audio quality of your device or|and that is BT-C1 is surerior in this respect. There are some capable smarphones out there nowadays that would be directly competing, but only few. Same goes for the laptops. Tablets are usually left aside when it comes to audio quality — good that they can play sound at all :) In our case it is Xiaomi Redmi Note 4X smartphone with low power&low quality sound processing and Lenovo Y500 laptop with regular integrated IntelHD sound card. So, we would opt to use external USB DAC based on more capable DAC&AMP chips to increase the audio quality.


3. Adding 32bit/384kHz and nativeDSD playback to a device

Another addition to the previous ones but in terms of source device compatibility with various audio formats. Passing the stream to modern external DAC would remove some source limitations and allow you to listen to more sophisticated formats. For example, Xiaomi Redmi Note 4X doesn’t want to eat DSD files unless you would connect external USB DAC. But even if it did — it would still be DSD over PCM and not DSD native.

4. Using as a remote Bluetooth receiver for speakers or headphones.

Perhaps, the most interesting option here. You can pair BT-C1 with 2 devices and stream music over Bluetooth AptX, AptX_LL or SBC from any source. The battery inside would last for about 6 hours to let you carry this device around in your pocket or you can just place it on the shelf and connect to active speakers or home system and charge from time to time. The maximum distance we’ve got was ~12 meters at open space.


Getting it to work:

No drivers are needed when connecting BT-C1 to Windows 10/MAC OS computers or iOS/Android smartphones. Just connect over USB with the corresponding cable and it would be recognized by the system. In case of Windows 10 it should be CSR8670 (playback and recording device).

One important thing to mention here: Colorfly didn’t bother to add some different types of firmware options or to create the additional ASIO driver. This leaves us with using OS mixer instead of avoiding its influence. For example, Foobar2000 would only operate normally when pushing up to 16bit/48kHz over WASAPI to BT-C1 DAC while 24bit or higher sampling rates would require to run it through (DS, OS mixer) because BT-C1 driver wouldn’t declare corresponding working modes. This is not a problem for the most of the users but severe audiophiles would suffer a lot.

Can’t tell anything about iOS or MAC OS — we don’t have any APPLE devices to test with.


Bluetooth connection:

BT-C1 supports pairing with 2 devices. Pairing process is very easy — just hold PLAY|PAUSE button for more than 3 seconds to get into pairing mode and discover it with your smartphone. Note that there is a mic in BT-C1 that allows to accept calls from this device. No problems with connecting and streaming music (AptX, SBC). Everything works as expected.

We would not describe sound quality when BT-C1 is connected to music source over Bluetooth. We are mostly interested in the maximum SQ this device is capable of which means testing it with the cable connection instead of using limited wireless protocols. Bluetooth works fine, shows no interruptions, connects over AptX or SBC and gives the maximum you can expect from this type of usage scenario.

Sound quality:

Tested with Xiaomi Redmi Note 4X, Lenovo Y500, Audio-Technica ATH-M50


Connected to smartphone (cable):

Power output of Redmi Note 4X smartphone is very close to BT-C1 — both have ~30-32mW. Therefore, we are not waiting much of a change in the overall dynamics, power of midbass or volume. In fact, there is almost no difference in max volume level between smartphone output and BT-C1. The main differences are about tonality and resolution. Lower frequencies have better extension, are much more textured, shaped and controlled with the external DAC. Layering is better as well not letting different instuments or the entire ranges to overlap. And there is also less evident elevation of upper mids resulting in more neutral sound. Treble portion gets more details and extension as well. The problem with Xiaomi output is that it lacks the clarity and mixes all sounds together… Most of the DACs we have tested had much better sound picture.


Connected to laptop (cable):

BT-C1 is showing the same — better resolution and extension of lows/treble, better separation/ layering and more neutral sound throughout the entire range, at least with the same volume level set on both outputs. However, midbass dynamics, power and overal expression gets better with the increase of volume of our laptop. This is not a surprise due to much higher output power and driving ability of Y500 integrated sound card. We feel that 32mW produced by smarpthome or BT-C1 is not enough to drive our 50Ω full-sized ATH-M50 headphones to the appropriate level. The situation got better after connecting BT-C1 to active speakers. Therefore, we can conclude that BT-C1 DAC does require external amplification to outperform our laptop and maintain significant SQ advantages at any volume level.

*BT-C1 battery is charging from a source device.

Compared to Audirect BEAM DAC:


Audirect BEAM is another USB DAC adaptor but is powered from USB and doesn’t have its own battery. It is smaller, more comfortable to carry in your pocket due to rectangular shape and less weight. The main difference to BT-C1 is that it doesn’t feature Bluetooth. Soundwise BEAM is having brighter tonality with more emphasis on upper mids and lower treble creating a feel of unnatural excessive clarity. Colorfly is more neutral in overall, with just a little impact on bass and great texturing of lows. Male and female vocals reproduced by BT-C1 sound more natural and balanced but at the same time less emotional.



In terms of audio quality Colorfly BT-C1 has managed to outperform both — smartphone and laptop audio outputs, proving once again that external DAC is more capable than many regular integrated audio HW solutions. There is no evident coloration to the overall tonality which means that this device is universal for performing any kind of genres and passing audio to any end point audio equipment. Moreover, the formfactor and physical controls allows to use this DAC in a pocket or as a part of audio system with ease. People from Colorfly could have gone further and make this device even better by releasing dedicated ASIO driver and supplying more output power. But even the current state of things is allowing numerous usage scenarios. The most interesting one is using BT-C1 to stream music to active speakers of audio system over Bluetooth. The rest is up to you!

You can purchase Colorfly BT-C1 at PenonAudio store


100+ Head-Fier
Pros: Small and lightweight,
Great sound for the price,
Clean background,
Easy to operate
Cons: Needs a bit of attention due the glass at the bottom
Colorfly BT-C1
The Bang for the Buck

About the company Colorfly:

Colorfly is a Chinese manufacturer of Portable Hi-Fi products, which is especially know for the Colorfly C4 Digital Audio Player (DAP) that was one of the few audiophile grade DAP’s in the market.

Colorfly Official Webpage:



I would like to thank Colorfly for providing me this sample via Penon Audio for review purposes. I am not affiliated with Colorfly beyond this review and these words reflect my true, unaltered opinions about the product.


The Colorfly BT-C1 is available on Penon Audio for 62,50 USD.

Purchase Link:


The Colorfly BT-C1 is a small sized wireless Digital to Analog Converter (DAC) with integrated and Amplifier (AMP), which can be connect to devices like Phones, Tablets, PC’s etc. that are supporting this protocol to enhance your music experience.

Package and Accessories:

The device comes in small and simple card box which contains the following items;

  • Colorfly BT-C1
  • Low profile USB Charge Cable
  • Stylish Lanyard


Design and Build Quality:

The outer shell of the Colorfly BT-C1 adopts a CNC processed aluminum alloy material in combination of a high-strength glass with anti-fingerprint, which has a black vinyl like design that looks stylish and is very compact.



There are three physical buttons and one volume wheel. The device has also a small LED, which lights up in three different colors (red, blue, green) and is giving several information’s about the device status, which I will explain later.



  • Sample rate : 32bit/192kHz
  • Output power : 32mW (32Ω load 1KHz/THD+N<1%)
  • Bluetooth version : 5.0
  • Distortion : <0.05%
  • DAC chip : ESS 9318
  • Signal to noise ratio : ≥125dB
  • Headphone jack : 3.5mm
  • Bluetooth Codec’s : SBC, MP3, AAC, APTX, APTXLL
  • Battery capacity : 270mAh
  • Charging time : 1.5 hours
  • Battery Life : ≥ 6 hours
  • Size : 42mm*42mm*12mm
  • Weight : 26g

Hardware / Power / Connectivity:

The Colorfly BT-C1 has some nice hardware specs for such a tiny sized Bluetooth device, which has some unique features like to connect two devices at the same time.

a) Digital to Analog (DAC):

The Colorfly BT-C1 has a relative new DAC (Digital to Analog Converter) of the company ESS Technology’s with the model number ESS9318 under the hood. The ESS9318 SoC supports the ESS patented 32-bit HyperStream architecture that can support up to 32-bit 384kHz PCM and DSD256 to deliver up to 125 dB SNR and -113 dB Total Harmonic Distortion plus Noise (THD+N).

b) Bluethooth Chip:

The Colorfly BT-C1 is using the latest Bluetooth SoC (System on Chip) of the Company Qualcomm with the model number CSR8670. Bluetooth and Bluetooth low energy radios, DSP and memory integrated into a single SoC to help reduce system complexity and eBOM while supporting devices with small form factor like the Colorfly BT-C1.


c) Bluetooth and supported Audio Codecs:

The Colorfly BT-C1 supports the latest Bluetooth 5.0 protocol, which is a big advantage over some other competitors, like the Astell&Kern XB10 that which is supporting an older protocol, the Bluetooth 4.1 Class2. This means whenever you pair the Colorfly BT-C1 with a Bluetooth device it selects the best possible codec that your audio source (DAP, Tablet, Smartphone) supports.

Supported codecs are SBC, AAC, APTX, APTXLL, which means that you no longer hear an FLAC, WAV, MP3, DSD, etc. music file. All audio formats will be decoded by the output device to PCM and then transcoded to aptX, AAC, SBC etc. via Bluetooth audio (in 16bit) to Colorfly BT-C1.

The maximum wireless operating distance of the CT-B1, without any barrier is about 10 meters, which I can confirm after my experiences with it.

What do these codes actually mean?


In digital audio data reduction technology, aptX (formerly apt-X) is a family of proprietary audio codec compression algorithms currently owned by Qualcomm.

The aptX audio codec is used for wireless audio applications, notably the real-time streaming of lossy stereo audio over the Bluetooth A2DP connection/pairing between a "source" device such as a Smartphone, Tablet Laptop or a DAP. Products bearing the CSR aptX logo are certified for interoperability with each other. (Ref: Wikipedia)


aptX LL = Low Latency is intended for video and gaming applications requiring comfortable audio-video synchronization whenever the stereo audio is transmitted over short-range radio to the listener(s) using the Bluetooth A2DP audio profile standard. The technology offers an end-to-end latency of 32 ms over Bluetooth. By comparison, the latency of standard Bluetooth stereo varies greatly depending on the system implementation and buffering. Solutions are available that use standard SBC encoding/decoding that achieve end-to-end latency of less than 40 ms. (Ref: Wikipedia)


Advanced Audio Coding (AAC) is a proprietary audio coding standard for lossy digital audio compression. (Ref: Wikipedia)


SBC, or low-complexity sub-band codec, is an audio sub-band codec specified by the Bluetooth Special Interest Group (SIG) for the Advanced Audio Distribution Profile (A2DP). SBC is a digital audio encoder and decoder used to transfer data to Bluetooth audio output devices like headphones or loudspeakers. It can also be used on the Internet.

It was designed to obtain a reasonably good audio quality at medium bit rates while keeping low computational complexity, having Bluetooth bandwidth limitations and processing power in mind. (Ref: Wikipedia)

d) Operation:

The Colorfly BT-C1 has three physical buttons and one volume wheel. The button in the middle is the play, pause and call answer button, which also turns the device on/off, when you push it for about 2 seconds. When you press it for 4 seconds it will activate the Bluetooth pairing mode, which is only needed for the first time (for each device).The left button is for previous and the right for next song selection.

The LED light gives us several information’s about the device status. The device is charging or has low power if the LED lights up in red. If the device is fully charged the light will be in green and blue when the pairing mode is activated.


e) Driving power & Hissing:

The ideal impedance range for the Colorfly BT-C1 is between 16 – 100 ohms and it has a driving power of 2 x 30mW @ 32ohms. The BT-C1 was able to drive all my IEM’s between 16 and 60 ohms to very loud volume levels and has a surprisingly silent background with very low hissing that was only noticeable with my DUNU Falcon-C, which is a quite sensitive IEM. The Colorfly BT-C1 has also quite enough juice to power my full sized Audio-Technica ATH M50 Headphone to relative loud volume levels.

f) Microphone:

The Colorfly BT-C1 has a build in microphone, which will automatically activated when you pair it with an Smartphone. Btw, the voice transmission and clarity was surprisingly good.

g) Battery Life:

The Colorfly BT-C1 is able to work continuously for about 5.5 - 6 hours with approx 70% volume, which is quite good for such a tiny device with wireless sound transmission capabilities.

Equipments used for this review:

  • DAC’s : Colorfly BT-C1, Astell&Kern XB10
  • USB Source : Samsung Galaxy S8+, Apple iPad Air2
  • IEM’s : Campfire Audio Polaris, SEMKARCH SKC-CNT1, Dunu Flacon-C
  • Earbuds : Astrotec Lyra Collection, Penon BS1 Official, Simphonio Dragon2+
  • Headphones : Audio-Technica ATH-M50


Albums & tracks used for this review:

  • Liquid Tension Experiment 2 – Acid Rain (Spotify)
  • Opeth – Damnation (Tidal Hi-Fi)
  • Megadeth – Sweating Bullets (Flac 16bit/44kHz)
  • Metallica – Sad bu True (Flac 24bit/96kHz)

  • Jehan Barbur – Yollar (Spotify)
  • Minor Empire – Bulbulum Altin Kafeste (Spotify)
  • London Grammar – Interlud (Live) (Flac 24bit/44kHz)
  • Laura Pergolizzi – Lost On You “Live at Harvard and Stone” (Tidal Hi-Fi)

  • Steve Srauss – Mr. Bones (Flac 16bit/44kHz)
  • Dire Straits – Money for Nothing (DSD 64)
  • Gothart – Jovano, Jovanke (Spotify)
  • Otto Liebert & Luna Negra – The River (DSF) – Binaural Recording
  • GoGo Penguin – Fanfares (Tidal Hi-Fi)
  • Casey Abrams – Robot Lover (Tidal Hi-Fi)
  • Yosi Horikawa – Bubbles (Tidal Hi-Fi)

  • Future Heroes – Another World (Tidal Hi-fi)
  • Lorde – Team (Flac 24bit/48kHz)
  • Tom Player – Resonace Theory “Album” (Tidal Hi-Fi)
  • Deeperise feat. Jabbar – Move On (Spotify)

The Sound:

Please note that this is a low budget DAC/AMP that means, all my comments about the sound quality are in consideration of this price range. The burn-in period for the Colorfly BT-C1 is about approx 75 – 80 hours.

The Colorfly BT-C1’s sound is close to neutral with a clean and balanced presentation tonality which has a touch of warmness.

The lower frequencies area of the Colorfly BT-C1 sound controlled and has pretty good extension for the price. What I have noticed is that there is lightly more sub-bass quantity then mid-bass, which is reaching to a pretty low register.

The bass is pretty fast and gives the sound a hint of fullness without to color the overall presentation too much, which is a great ability for such a tiny device at this price point.


The midrange of the Colorfly BT-C1 sounds uncolored and with only a small amount of coloration, which is a result of a hint of warmness that is, produced form from the lower frequency area. One of great features of the BT-C1 is the smooth and pretty transparent presentation of the midrange, which excels pretty good with both female and male vocals. I have really enjoyed the vocal presentation of the Colorfly BT-C1, especially female voices like Jehan Barbur and Ozgu Ozman (Minor Empire.

The only downside in this area is the missing of some fullness, which was remarkable with the Audeze iSine20 and the Dunu Falcon-C.

The performance of the BT-C1 regarding to the midrange definition and detail retrieval of instruments is outstanding, when I remember that this devices cost only 62.50 USD.

There upper midrange sounds fairly soft and quite controlled with only a small amount of harshness, which was noticeable with the Dunu Falcon-C that is quite sensitive in this regarding.



The treble range of the Colorfy BT-C1 has pretty good control and extension, which doesn’t tends to sibilance and harshness. It is fairly neutral and uncolored, which is again a nice ability for a entry level Bluetooth device. Instrument like pianos, violins and side flutes sounding crisp fairly detailed without to be harsh.

The upper treble region is missing some energy, which sounds otherwise pretty controlled and with a above average detail retrieval.

Soundstage and Separation:

The Colorfly BT-C1 delivers a quite a spacious soundstage, which has an above average depth and natural expansion. The positioning of instruments and vocals is pretty good.


Colorfly BT-C1 vs. Astell&Kern XB10 (using 2.5mm balanced out)


The Astell&Ken XB10 was a pioneer for many brands, and a good example to show us that small wireless Bluetooth devices can sound pretty good.

When it comes to sound, the Astell&Kern XB10 has the warmer and brighter tonality compared to the Colorfly BT-C, which has less emphasis on the top and lower end with its more natural presentation.

The bass of the Astell&Kern XB10 has more body and weight especially in the mid-bass area where the Colorfly BT-C1 sounds more balanced and clean. Both devices have a fast bass response, while the sub-bass of the XB10 are reaching to a slightly lower register. The bass extends pretty well on both devices, while the Colorfly BT-C1 has the upper with its better control.

The midrange of both devices is sharing a fairly amount of detail, where the Colorfly BT-C1 sounds slightly cleaner and with additional transparency. The Astell&Kern XB10 sound a bit too veiled for my taste, which performs otherwise pretty good in this area. Vocals have a hint more weight with the XB10, but the BT-C1 sounds more lifelike especially with female vocals. The overall detail level of instruments and vocals is lightly better with the Colorfly BT-C1.

When it comes to the treble range, the Colorfly BT-C1 and Astell&Kern XB10 are pretty detailed. The Colorfy BT-C1 has the upper hand for control and extension. The XB10 sounds slightly brighter then the BT-C1, which is resulting to harshness problems, especially with some bad recorded Metal songs like Metallica’s “Sad but True”. The Colorfly BT-C1 a bit more distant and transparent compared to the Astell&Kern XB10.

Astell&Kern XB10 and Colorfly BT-C1 have an above average soundstage performance, with moderate level of wideness. The biggest difference is for depth, where the Colorfly sounds more realistic and precise.


The Colorfly BT-C1 is a small but very capable device that will change the prejudices against Bluetooth devices, due the surprisingly uncolored and detailed sound for a Bluetooth DAC/AMP which is sold for a reasonable price.

Summary (plus and minus):

  • + Small and lightweight
  • + Great sound for the price
  • + Clean background
  • + Easy to operate
  • - Needs a bit of attention due the glass at the bottom
This review was originally posted on "Moonstar Reviews" :

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