EarStudio ES100 MK2-24bit Portable High-Resolution Bluetooth Receiver/USB DAC/Headphone Amp with LDAC, aptX HD, aptX, AAC (3.5mm Unbalanced & 2.5mm Balanced Output)

Would rate 6-Stars if I could.If you're here because you REALLY love your wired headphones and don't want any of the current BT garbage, you're not alone and you've found your solution. If you want to get right to the advice, buy this BT-DAC right now and start enjoying full, beautiful sound, no artifacts, and a truly usable GEq and DSP.If you want more of the review, read on:First, I'm a...erm..."intermediate" audiophile. I'd never pay $100k for a pair of speakers nor $1k for interconnects, but my listening system is expensive and high-resolution and I know what that sounds like. In the past, I've used Shure IEMs exclusively. Apple decided to turn off ("it's a hardware issue" - is the BS line to get me to "upgrade") audio transmission to my lightning port, so I've been hunting for something satisfying for the better part of 6 months. I have AirPods - they're utter garbage if you like hearing the music you're playing. I have Bose 35s and they're passable, especially in the isolation department on aircraft or noisy locations, but the low and punchy-bass extension is anemic and if pushed, they distort (more on one ear cup, making it intensely annoying). The Bose 35s also lose effectiveness the moment you wear a baseball cap, sunglasses, or eyeglasses (an issue that IEMs don't summer in any way), they're clunky, and they're decidedly not sweat or water-resistant.Enter the EarStudio ES-100 to literally put my world back to normal.THE BAD:Me, personally: I can't find any major detractors currently - it's flawless so far as I can tell. The build materials might not be the very best, but it's $99, so I wasn't expecting aircraft aluminum.Others: The BT calling is not the best, but this thing isn't designed for that - it's for music and it's completely usable and clear - just some little artifacts on certain calls.THE GOOD: [Everything]Sound Quality = Excellent. It's probably not the most transparent device available, but it is damn good, rivaling my DragonFly Red with far more to offer in terms of control (see below)Power = Excellent. The amplifier(s) are powerful and offer punch that the iPhone simply doesn't have.DSP = Amazing.Companion App = Amazing.Control = Amazing. There's control over nearly everything, with clear explanations below the controls as to how they work and why.GEq = Amazing. The GEq allows you to save [at least 4] preset curves to match your different headphones or different musical genres. It's artifact-free so far as I can tell, and I've not gotten any clipping at all. This is HUGE, as different headsets have different sound signatures, even from the same manufacturer, and this is a one-touch solution to those differences, once configured (which is very easy).Bonus 1: The biggest issue with the iPhone is that you cannot apply an equalizer curve across all of your music services - it works for Apple Music, but not, for example, Pandora. The EarStudio's GEq completely fixes this issue, applying your chosen curve(s) across all outputs. Truly amazing the difference it makes.Bonus 2: The one detractor to IEMs and closed-back circumaurals (big "can" headphones) is that the isolation from the outside sounds might not be ideal due to safety reasons (work environment or driving in a car) or concern for children (whose voices you might need to hear). The DSP engine allows you to pull as much or as little ambient sound and integrate it to your sound stream! What does this mean? It means you can enjoy all of the isolation features of IEMs or closed-back headphones whenever you want but then make it so traffic noise, kids, or other environmental sounds come through - only when you want and only to the extent you want. Even better? There's a hot-button for this, allowing you to turn it on and off instantly. Imagine this: You're on an airplane enjoying music without engine whine. Someone taps you to talk, but your isolation is so good, you can't hear them. With the hot button (both a physical one on the body of the EarStudio and a virtual on on the companion app), you can instantly mix in the outside sound (one-touch) to hear it and then re-isolate again with another touch. You need not have less-isolating headphones or IEMs in order to safely or effectively (or selectively) hear outside sounds. Even on my Bose 35s you have to tap the isolation button twice to get this.In short, the sound is awesome, the controls amazing, and the thinking about usability and functionality are amazing. I thought I was going to get a bunch of chopped up Chinglish and a passable device, but...man, they got it so right. Bravo to the people at Radsone - this is one of the very best audio products I own.

Tldr? Buy it! Seriously...I had/have the Hidizs Sonata HD II USB DAC, but it kept detaching in my pocket. and it made the phone unwieldy to use, as I had the DAC connecting to my Little Bear B4-X tube amp, and the phones connected to that.Now I have the phones connecting to the tube, but the tube connects to the E100Mk2, (Mk2) which connects via the Bluetooth LDAC codec to my Phone. OnePlus 7t running Android 10. On which I run USB Audio Player Pro (UAPP) which I have route audio to Bluetooth, which allegedly makes the signal cleaner before being sent to the Bluetooth receiver. I'm running in BitPerfect mode. Set Android volume to full to use the Analogue volume of the MK2On ease of use alone, this is a winner, I can use my phone as normal. It has a phone pass through with a mic built into the Mk2, you can speak and be heard with the MK2 in your pocket. Functionally, it has twin DAC's and balanced output via 2.5" it drives the Tin HiFi P1 (Planar Magnetic) easily, and that is difficult to drive. I'm currently running 3.5" SE but some balanced 2.5" cables have just arrived from China. It also has a great full featured app. Allows you to tweak the roll off of the DAC live with music playing. So you can switch until you find one you like. It has a full EQ, (might be fixed parametric, not sure, not used it.) The battery charges fast by Mini USB. Lasts about two days of medium use. There is a little icon on the Android notification bar, that turns read when it needs to be charged at about 15-20% The button layout is good, with volume under the 3.5" output and power/action FF & RW under the 2.5" output. USB is on the bottom.Bluetooth wise it functions well with my Withings Steel Series HR smartwatch which is also always connected. Supports gapless playback, etc. It also integrates as a default headphone out, so it works with other Apps like Amazon Music HD, etc.All that aside, where it really shines is in how it renders music. With my Hidizs USB DAC, (which was an upgrade over my old Dragonfly Black, now plugged into my PC) the Mk2 renders a large sound stage with excellent imaging. The Tin HiFi P1 was a very intimate experience via USB, and required a good 85-95% volume to sound good. The Mk2, is night and day. So much so that the P! is now my daily driver instead of being carried in case I wanted to listen to Adelle's "21"It pretty much excels at anything else you plug into it, I've tried the Tin T4, the QKZ VK4, the Shuoer Tape (electrostatic) the BLON bl03, the VIE Bonus earbuds and the ikko OH10 all of them sound better than they did on the Hidizs USB DAC. However it's the P1 that has changed the most. I really love what it does in the way of detail retrieval and vocal reproduction. I simply hear things with the P1 I don't hear with anything else.A minor note about the Little Bear Tube amp. Essentially the tubes are microphonic. This means that they will pick up local radio broadcasts, ( by local I mean "hyper local." GSM and Bluetooth in your pocket. etc.) You can get past some of this by keeping you phone in a different pocket.and getting a longer interconnect, from the Mk2 to the tube. Otherwise you get a constant low level intermittent tone during silence. It doesn't affect music, since any music drowns it out. However if you tube it, that's what you have to put up with.Why tube? It make the sound warmer, wider with more "air". If you're using a tube, just make sure Android and the Mk2 volumes are at max, then use the tube as the final volume control. This allows you to drive pretty much anything. With balanced, (the Little Bear is a balanced tube) giving you even more power if you need it.As you can no doubt tell, I'm really impressed with the Mk2. It's a truly fantastic bit of kit. Well worth the asking price, and if you're using a USB DAC, or you just want to make your phones Bluetooth enabled then this is the device to buy. Seriously good.