Radsone EarStudio ES100: The Little Bluetooth/USB Device with a Big Sound

Earlier this year, a Dutch user on Head-Fi contacted me asking me about planar headphones – specifically the Fostex T50RP and we started chatting about modding and somehow discussed Bluetooth devices. I had told him I had the Fiio BTR1 and was pretty satisfied with it but he told me he was keen on this new device by an unknown company called Radsone. It was the Ear Studio ES100. I had seen glimpses of it on kickstarter or Indiegogo, I forget, but I was always very skeptical of those no-name brands making easy to copy Bluetooth devices. There’s been many of them, headphones, adapters, etc, which are overpriced garbage that you see as imitations of imitations of products you see on Amazon or Ali Express.

But then I started to read more on this ES100 and it actually looked legit. It featured dual DAC and dual amp architecture with both single ended 3.5mm and 2.5mm output. I took a gamble. Sure why not?

It was available on Amazon with Prime shipping, so I could easily return it if I did not like it. Well, I’ve had this item for over 6 months now and use it almost daily. It’s a fantastic piece of hardware and has garnered an ever growing fanbase because it really is flat out awesome.

It’s $99. The same price as many USB DACs like the popular Dragonfly from AudioQuest, or the Fiio Q1 Mk2, however this one features balanced output. It also can be used not only as a USB audio device, but as a high definition Bluetooth device as well. It supports every CODEC – that’s SBC, Apt X, Apt X HD, AAC, and LDAC! LDAC on this sounds superb.

And best of all, it has a mobile app that lets you tweak settings to your heart’s content and has a system-wide EQ. I love this feature the most. Being able to EQ how I want is a great for IEMs like the iSine on Android where we don’t get the lovely Cipher cable option.

The sound quality is also excellent. I forget I am using wireless sometimes, especially on LDAC and Android Oreo or Pie, which have LDAC support built-in. And this device, through it’s balanced 2.5mm connection, can power even my over-ear Planar Magnetic headphones well. With most IEMs, there’s no issues with noisefloor, and you can easily use them with the 3.5 or 2.5mm connection, although I find the 2.5mm just a tad better.

As a USB device, this works well as a USB Audio for your PC or laptop, and the device is super small that you can put it in your pocket or use the attached clip to clip to your shirt.

As a recommendation, I prefer to use this with a short IEM cable – something like 40 cms or less. This helps reduce cable clutter if you are using the clip. It’s perfect for walking around and enjoying high quality sound…

And I know I sound like an infomercial or am hyping this item up, but I think it deserves all the credit in the world because the company has done a marvelous job making it, and have been very receptive to the audio community with listener feedback. They’ve continually improved the firmware and app features based on user input. I’ve exchanged messages directly with their Technical Director and you can tell they have a strong desire to build a great product and it shows.

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