Yin Lu Mei is a Chinese electronics company that specializes in making audio devices. In this review, I’m looking at the Yin Lu Mei B2, a portable Bluetooth DAC/amplifier with an AKM AK4497 DAC Chip and support for all the latest Bluetooth audio codecs including LDAC, aptX-LL, and aptX-HD. It also has a 4.4mm balanced output and can be used as an external DAC. But where this little guy really surprises is in its sound. Read on to find out why.
Disclaimer: This sample was provided for the purpose of an honest review. All observations and opinions here are my own based on my experience with the product.
- Lightweight chassis
- Decent battery life
- Stable Bluetooth connectivity
- Unique sonic character and wide-ranging synergy
- Output power
- User’s Manual only includes Chinese language
- Loud pop when turning on the unit
- Glass sides are fingerprint magnets
Yin Lu Mei B2
Package and Accessories
The Lin Yu Mei B2 comes in a basic black flip-top box with a black cardboard sleeve. Inside the box, the B2 is seated in a white foam insert and covered in a sheet of foam for additional protection. Apart from the DAC/amp, the only other things in the box are a USB Type-C cable and a user’s manual which is, unfortunately for us monolinguists is printed entirely in the Chinese language. Still, if you’ve used any portable Bluetooth DAC before (FiiO BTR3, Shanling UP4, etc.), you won’t have any trouble using this device.
Design and Functionality
Starting with its physical qualities, the B2 has a CNC crafted aluminum chassis with a double-sided tempered glass design. With dimensions of 88mm x 75mm x20mm, it’s small enough to comfortably fit into a shirt or jeans pocket.
Weighing in at just 180g, the B2 is lighter than it looks and I’ve never felt any burden carrying it around with me. There’s quite a lot going on in terms of ports, jacks, and buttons, so I’ll cover each side of the device separately.
Buttons, Switches and Stuff
On the front panel are (from left to right):
- 4.4mm balanced output
- 3.5mm single-ended output
- 3.5mm line output
- Line output select switch (single-ended/balanced)
- Alps potentiometer
The volume pot has a very smooth action with just the right amount of resistance. It’s easy to adjust and at the same time gives you a very precise level of control to dial in your exact desired level.
The left side has 2 LED indicators, one for charging and one for Bluetooth. The prior lights up red when charging and blue when fully charged. The latter flashes blue when Bluetooth is active.
Over on the right side are three power and playback control buttons. The first is to power on and off the unit, in addition to stop/start music playback and answer/end a call (yes, the B2 supports phone calls). The other 2 buttons are for the next track and previous track.
Moving around to the back panel, we find (from left to right):
- USB for for charging/DAC data transfer
- Built-in microphone
- Coaxial out/in select switch
- 3.5mm coaxial in/out port
Internals and Technical Stuff
At the heart of the B2’s sound is an AKM Velvet Sound AK4497EQ DAC chip. Bluetooth 5.0 functionality is handled by a Qualcomm CSR8675 which handles all the major Hi-Res wireless audio codecs such as LDAC, aptX-LL, and aptX-HD, etc.
For the op-amps, B2 has dual LPF – OPA1612, enabling a fully balanced architecture enabling both a balanced Line Out and a balanced 4.4mm headphone output. While we’re on the subject of the output, the B2 can do 220mW (Single-Ended) and 440mW (Balanced) @16 Ohm. Output impedance is 2.2 ohms for single-ended and 1.1 ohms for balanced. That means the B2 should also work well with sensitive, low-impedance in-ear monitors.
Pairing with the Lin Yu Mei B2 is super easy. I tested it with my iPhone and several Bluetooth-enabled DAPs and they all had no problem connecting with the B2. During my testing, I did not experience a single cutout or dropped connection.
When on the go, I keep the B2 in my jacket, shirt or pants pocket, and my phone or DAP in my pants pocket. At home, I generally have the source on either my desktop or living room table. The signal range seems to be in line with other Bluetooth amps I’ve tried and I could move freely around my house without signal drops.
I tested the microphone on a call using the B2 and Sivga Phoenix headphones. The microphone works really well and the person I was speaking too said my voice was coming through very clearly. I could also hear them just fine and was able to dial in the volume to the precise level that I wanted.
The B2 has a 3200 mAh battery that is rated for up to 15 hours of playback time. That seemed to be fairly accurate with my experience when using the device at moderate volume. A full charge takes around 1.5-2 hours via the USB Type-C port. Overall, I think the battery life is pretty decent for something with this amount of output power.
Sources used for testing:
- iPhone -> YLM B2 (AAC)
- FiiO M6 -> YLM B2 (LDAC)
- Shanling M5s -> YLM B2 (LDAC)
- PC -> Foobar2000 -> YLM B2 (USB)
The Yin Lu Mei B2 performs pretty much as I expected in terms of Bluetooth and battery performance. In terms of audio quality though, that’s another thing entirely. I’m blown away by how good this little DAC/amp sounds with IEMs across the board. It seems to have a magical quality that brings out the best in whatever you pair with it, whether that be budget or expensive gear.
The B2’s output impedance (2.2 ohms for single-ended and 1.1 ohms for balanced) probably has something to do with its wide-ranging synergy with IEMs. But the B2 also makes my full-size headphones sound great too.
One of the things that the LVM B2 does is bring out the bass in your transducers. But I don’t mean like your average bass boost; it’s neither that extreme nor that messy. Let me try to explain it a bit better. B2 has a full-bodied, muscular sound but it is exceptionally clean, relatively fast and non-destructive.
What I mean by that is that the overall resolution and level of detail aren’t negatively affected. In fact, the B2 has a pure black background that enhances instrument separation and soundstage. I guess you could say it falls ever so slightly on the warmer side of neutral but the catch here is that it also has a liveliness and crisp clarity on top of that.
So what you end up with is a sound that’s very approachable and somewhat easygoing but at the same time, it’s detailed, clear and highly resolving. The treble is airy, extended, revealing and yet still somewhat relaxed. It gives you a sense of energy without any stridency and it’s forgiving on less than stellar recordings.
Moving on to the midrange now and the Yin Lu Mei B2 has fairly neutral mids that gives vocals and instruments a natural character. Notes have just the right size and are neither too thick and warm nor thin and clinical. The B2 just finds that perfect balance between body and clarity that creates a natural and organic tone.
CCA CA16 (3.5mm single-ended)
Nice weighted, punchy bass with medium attack and fast decay. Good vocal clarity with vocals placed in front of the listener as though you were a few rows away from the front of the stage but still close to the action.
Good treble extension, crisp and detailed sound but very smooth. Nice depth in the soundstage with good instrument separation and black background.
Tin Hifi P1 (3.5mm single-ended)
I chose to test the P1 with the 3.5mm single-ended output since that’s the default cable configuration out of the box. Although the P1 is notorious for being a power hungry beast, the YLM B2 has more than enough power to drive it even without using the balanced output. Anywhere over around 75% was too loud for me to handle.
With enough driving power, the P1 shows it can easily provide a sufficient deliciously textured bass response. The midrange has awesome resolution with each instrument occupying its own space in the soundstage. Electric guitars sound gritty and lifelike, vocals rich and articulate and everything else is a delight for the ears.
One thing I liked in particular with this combination was the P1’s treble which came through with crisp, detailed and extended notes.
DUNU DK-2001 (4.4mm balanced)
Tight, punchy bass with solid impact. Great sub-bass extension and rumble. Clean, resolving midrange with good instrument separation and upper midrange presence. Midrange has a lively but natural sound with lots of detail.
Treble has very good extension, fairly energetic but even response with some sparkle and airiness. Soundstage is quite large with fairly even in width and depth.
Sivga Phoenix (3.5mm single-ended)
Robust, full-bodied bass with great control and extension. Clear midrange with a black background. Very good overall resolution and clarity. Vocals are articulate with a fairly forward presentation and not at all recessed or coloured.
The treble is slightly relaxed but has good extension. It has an airiness and open feeling with good vocal density and note solidity.
Thieaudio Phantom (4.4mm balanced)
When connected to the B2 the Phantom feels more balanced and less veiled in the midrange. To be honest, this pairing had me considering revising my rating of the Phantom for a more positive one. And I probably would have if the pleather on the headband wasn’t disintegrating despite being only a few months old and having relatively little use.
Wonderful bass extension with really nice tonal balance across the board. As I said above, the midrange sounds more clear and articulate, with the great resolution that you usually get from planar drivers. Vocals still have a hint of a veil but show a definite improvement. The treble is fairly laidback with a fast decay but still feels light and airy.
I really had no idea what to expect from the Yin Lu Mei B2. Until recently, the brand has been sold exclusively to the local Chinese market; something that is made evident by the user’s manual which doesn’t contain any English or other foreign languages.
On top of that, the B2 doesn’t come cheap. There are a lot of tempting alternatives that can be found at lower prices. But the B2 does have a lot of added versatility with its coaxial in/out, balanced headphone and line outs, built-in microphone and USB DAC functionality. Furthermore, it’s got enough power to drive a wide range of demanding headphones.
But what gets me excited is the sound that comes out of this thing. Whether using it wired or wireless, the B2 seems to bring out the best in my IEMs and headphones. It’s simply a joy to listen to and for me, that’s the bottom line. Recommended!
Decoding Chip: AK4497EQ
LFP Operating Amplifier: OPA1612 x2
Bluetooth Chip: Qualcomm CSR8675
Bluetooth Version: 5.0
Bluetooth Protocol: LDAC, APTX-LL，APTX-HD，APTX，AAC, SBC
Coaxial Processing Chip: AK4118 24Bit/192Khz
Support USB DAC: Yes
Input Interface: USB DAC Input, 3.5mm Coaxial Input
Output Interface: 3.5mm Coaxial, 3.5mm Single-End LO, 3.5mm Balanced LO, 3.5mm Out, 4.4mm Balanced Out
Output Level Value: 1.8 VRMS (Single-End), 3.6 VRMS (Balanced)
SNR: 113dB (Single-End), 119dB (Balanced) @1kHz 32 Ohm
Distortion: 0.0008%(Single-End), 0.0007% (Balanced) @1kHz 32Ohm
Output Impedance: 2.2 ohms (Single-End), 1.1 ohms (Balanced) @1kHz 32 Ohm
Output Power: 220mW (Single-End), 440mW (Balanced) @16 Ohm
25mW (Single-End), 50mW (Balanced) @150 Ohm
Battery: 3200 mAh for up to 15 hours use
Size: 88mm x 75mm x20mm