Finally, a great Bluetooth companion for Pro 82 - FIIO BTR3K!
Left to right - Earstudio ES100, FIIO BTR3, FIIO BTR3K, FIIO BTR5, Qudelix 5K, xDuoo XQ-23, Shanling UP2, Shanling UP4.
Build/usability
Build quality is great, it doesn't get any better.
BTR3K comes with a removable plastic clip (like BTR5), unlike BTR3, which has a clip on its back permanently.
The "Volume up/down" button is much better than on BTR3, you can really feel it.
Volume resolution is 60 steps, so you can adjust it to your exact liking.
Using the FIIO Control app, you can use a 10-band equalizer (not over LDAC though), and choose different types of low-pass filters (mostly affects bass).
If you'll set BTR3K to "USB DAC first", BTR3K will still appear as the current audio deivce on your phone, but media playback on your phone will be muted.
However, if a call comes in - you will hear it through BTR3K.
I wish there was an option to turn off Bluetooth when using a wired connection, but there isn't one - so I have to disconnect BTR3K from the phone manually each time (to reduce noise interference in the wired mode).
BTR3K vs BTR3
Both have the same dimensions, but BTR3K is 2.5 grams lighter.
BTR3K looks very similar to BTR3, but it adds a balanced 2.5mm output at the bottom, and moves the USB port to the top.
BTR3K has slightly larger battery - 330mAh vs 300mAh, but both have the same battery life (up to 11 hours).
BTR3K is using Bluetooth 5.0 vs 4.2 in BTR3, but it is losing LHDC support because of this.
BTR3K is using a slightly more advanced DAC AK4377A vs AK4376A in BTR3, and has two of them.
Just like the much more expensive BTR5, BTR3K is using two independent crystal oscillators for 44.1kHz and 48kHz, reducing jitter.
Both drive 25mW into 32Ohm from the 3.5mm, but BTR3K can drive up to 78mW using the balanced 2.5mm output.
The only disadvantage in BTR3K is losing NFC, but I have never considered that feature important - you only use it once to connect to a transmitter (and not all of them support NFC anyway).
Sound impressions
BTR3K sounds exactly the same using Bluetooth (LDAC 660/990), as it does wired - so you will get consistent sound regardless of how you use it.
While BTR3K is limited to 16bit/44.1kHz and 16bit/48kHz in USB mode, I had no problem playing higher resolution files in Foobar2000, without any noticeable degradation in sound quality.
With Takstar Pro 82 v2, BTR3K was a revelation - I did not expect this level of performance from such a tiny and cheap device.
It's border-line synergy combo - but wrapped into a single device, which also provides Bluetooth!
Pro 82 v2 sounds very musical on BTR3K, regardless of connection type.
Throughout the entire frequency range, there is nothing to fault - even the bass is nearly perfect in both quantity and quality, only being very slightly improved by adding O2 amp.
BTR3K hits really hard with Pro 82 v2, and the bass has full body - really surprising for such a tiny device.
BTR3 sounded very transparent with Pro 82 v2, but the notes were too thin.
BTR5 had proper weight of the notes, but added a slight warm veil, losing the transparency.
BTR3K resolves both issues - the notes have the proper weight, while retaining perfect transparency, without even a hint of any veil.
BTR3K adds some very slight euphony to the sound, as if it has a hybrid tube pre-amp - I find this very pleasurable and accommodating in long listening sessions.
Thanks to this slightly euphonic sound, BTR3K is quite forgiving to badly recorded/mastered recordings, despite excellent detail retrieval.
Only comparing BTR3K directly vs SMSL Idea (Sabaj DA2) + O2 amp, I was able to rule it out as a synergy combo.
Standalone, it sounds better with Pro 82 v2 than any device in the picture above, except maybe Qudelix 5K - not because I think it sounds better, but only because I haven't tested it extensively yet.
Not only that, but BTR3K even sounds better standalone than SMSL Idea/Sabaj DA2, which sound a bit too dry without O2.
Unfortunately, BTR3K doesn't have the same synergy with O2 as Idea/DA2 - it sounds too perfect on its own to really benefit from an amp.
P.S. I do prefer ES100's sound for my IEMs, but I currently have 3rd one in 2 years dying on me - so can't really recommend it.
Microphone
The microphone is very good, I constantly use BTR3K for phone calls/Zoom/Teams.
Conclusion
BTR3K sounds much better than much more expensive Bluetooth receivers such as FIIO BTR5 or Shanling UP4, at a much lower price.
This is really a no-brainer, a universal device that provides great SQ over any type of connection.
If you are looking for a single device to use in any situation - BTR3K is the answer.
If you listen to music mostly at home/office, you still would be better off investing in a synergy combo for Pro 82 -
Comparison of DACs/Amps
Where to get
You can get it here:
https://www.aliexpress.com/item/4000849710696.html
Its normal price is 70$, but during the 11.11 sale (which is actually 2 days - November 11th and 12th), you can use Select Coupons to get 6$ off that, and then you can get "6$ off 50$" coupon playing Energy Lab in the Aliexpress app - bringing the total down to
58$!!!
Don't miss this opportunity!