[seanheis]

Hi. What kind of adapter cable do I need to connect my Bluemini R2R Dongle to my stereo speaker amp? I think I might need female TRRS to stereo RCA...but that appears to be a very rare adapter...like I only see one company on the entire internet (My Cable Mart) selling a 4 conductor TRRS female to stereo RCA adapter. Obviously there are a ton of female TRS to RCA adapters but this Bluemini is using TRRS. Thanks for any help or just to tell me I'm stupid

 

[samandhi]

Hi. What kind of adapter cable do I need to connect my Bluemini R2R Dongle to my stereo speaker amp? I think I might need female TRRS to stereo RCA...but that appears to be a very rare adapter...like I only see one company on the entire internet (My Cable Mart) selling a 4 conductor TRRS female to stereo RCA adapter. Obviously there are a ton of female TRS to RCA adapters but this Bluemini is using TRRS. Thanks for any help or just to tell me I'm stupid

That is because you dont' want to go from balanced to single ended (TRRS to TRS). You would short the grounds. A more common adapter would be a 4.4mm TRRS to dual XLR balanced adapter.

Having said that, you could commission one to be made that will work (though it will probably be a bit pricey, in which case you might be better to just order a BT receiver). For instance, HERE are a bunch that would work. iFi makes a couple as well (seen HERE).

I am assuming that you are trying to use the Bluemini as a BT receiver for your speaker amp?

 

[ardilla]

That is because you dont' want to go from balanced to single ended (TRRS to TRS). You would short the grounds. A more common adapter would be a 4.4mm TRRS to dual XLR balanced adapter.

Hi. What kind of adapter cable do I need to connect my Bluemini R2R Dongle to my stereo speaker amp? I think I might need female TRRS to stereo RCA...but that appears to be a very rare adapter...like I only see one company on the entire internet (My Cable Mart) selling a 4 conductor TRRS female to stereo RCA adapter. Obviously there are a ton of female TRS to RCA adapters but this Bluemini is using TRRS. Thanks for any help or just to tell me I'm stupid

The Bluemini uses a 3.5 TRRS connector and i'd be surprised if it was truly balanced.

You could measure if the ground is shared with a multimeter

Someone got it working here:

https://www.reddit.com/r/headphones/comments/132f3py/hifiman_bluemini_r2r/

,

 

[samandhi]

The Bluemini uses a 3.5 TRRS connector and i'd be surprised if it was truly balanced.

You could measure if the ground is shared with a multimeter

Someone got it working here:

https://www.reddit.com/r/headphones/comments/132f3py/hifiman_bluemini_r2r/

,

It is indeed "truly" balanced. And just like the article you linked suggested, it CAN work just fine with any old adapter (3.5mm TRS female to dual RCA cable), but as (also) mentioned on there, you would be shorting grounds at the amplifier on the Bluemini. This can have consequences as little as flat sound, etc... (all the things mentioned on that link). But, what isn't mentioned there is that because you are shorting out the grounds, there is a good possibility that over time you will blow out the amplifier section of the Bluemini.

@seanheis, you can take it seriously or not, it is totally up to you how you move forward. I am just letting you know the facts here.

https://www.moon-audio.com/balanced-adapters-caution

 

[seanheis]

Thanks for the link to the moon audio adapter warning...Moon is clearly warning against taking single ended and converting it to balanced...
However, I believe I am taking balanced and converting to single ended if I use a 4 conductor TRRS female to stereo RCA adapter.

Here is what Moon audio says in that same article: "You can convert a balanced connection back to single ended. This is not a problem at all as long as your main headphone cable is balanced, then you can add an adapter cable. For example, we make adapters that convert the Astell & Kern balanced 2.5mm plug to a 3.5mm plug for use with your phone or another device that only has a 3.5mm or 1/8" jack."

@samandhi I would be using it as a USB dongle DAC

 

[ardilla]

It is indeed "truly" balanced. And just like the article you linked suggested, it CAN work just fine with any old adapter (3.5mm TRS female to dual RCA cable), but as (also) mentioned on there, you would be shorting grounds at the amplifier on the Bluemini. This can have consequences as little as flat sound, etc... (all the things mentioned on that link). But, what isn't mentioned there is that because you are shorting out the grounds, there is a good possibility that over time you will blow out the amplifier section of the Bluemini.

@seanheis, you can take it seriously or not, it is totally up to you how you move forward. I am just letting you know the facts here.

https://www.moon-audio.com/balanced-adapters-caution

That's why I suggested measuring if the ground is shared.

 

[samandhi]

Thanks for the link to the moon audio adapter warning...Moon is clearly warning against taking single ended and converting it to balanced...
However, I believe I am taking balanced and converting to single ended if I use a 4 conductor TRRS female to stereo RCA adapter.

Here is what Moon audio says in that same article: "You can convert a balanced connection back to single ended. This is not a problem at all as long as your main headphone cable is balanced, then you can add an adapter cable. For example, we make adapters that convert the Astell & Kern balanced 2.5mm plug to a 3.5mm plug for use with your phone or another device that only has a 3.5mm or 1/8" jack."

@samandhi I would be using it as a USB dongle DAC

You are welcome!

I realize that it is a bit confusing as to a comparison to what you are trying to accomplish, and after re-reading it, it is indeed confusing the way they explain it, but they are saying the right thing in a confusing way, so look at it this way.... Always think of it from the directional flow standpoint; it makes things much easier to understand and put into perspective, because MoonAudio is NOT warning against going from balanced to single ended; just the opposite in fact. In this scenerio the flow of electricity is from the source (Bluemini) to the device (speaker amp). If you are coming from a balanced connection from the source (in this case, your Bluemini) to a single ended connection (your speaker amplifier) that is where the issue happens. If you were coming from a single ended source, you could use either balanced or single ended without worry.

Here you can see (visually) why coming from balanced source to a SE conneciton is bad. Think of it as being similar to this: If you take a household extension cord, and cut the other end off (the end that powers the equipment), and tied any of those wires together, and plugged it in, this is essentially what you are doing when going from balanced from the source to SE in to any device/head gear (with a bit less sparks of course). This of course can happen if you use a SE cable or if the device (headphones, amp, etc..) is SE, much like your amplifier is (denoted by using two RCA jacks; this is SE).

Spoiler

The source in your case is your Bluemini, and the input in your case is the speaker amplifier

Think of it this way, if you can't remember:

• Source = any balanced connection (2.5mm, 3.5mm balanced not SE, or 4.4mm) out to any balanced cable or device = Good!
• Source = any balanced connection (2.5mm, 3.5mm balanced not SE, or 4.4mm) out to single ended cable or device = BAD!
• Source = single ended connection out to any balanced cable (2.5mm, or 4.4mm, or 3.5 balanced) or single ended cable or device = GOOD!

That's why I suggested measuring if the ground is shared.

I see. While I haven't tested the R2R Bluemini, I have tested the Bluemini from the OG Deva the last time someone on here got confused about balanced vs. SE with these headphones (they didn't make it very intuitive with these).

 

[ardilla]

If the Bluemini is that good, Hifiman should maybe consider making a similar device with only 4.4mm out?

 

[samandhi]

If the Bluemini is that good, Hifiman should maybe consider making a similar device with only 4.4mm out?

Good point. However, I am not sure that they intended it to be used as a DAC/amp for anything bit the Deva/Pro. Haha maybe they just didn't know that it could be better than a lit of dongles out there?!

 

[Surf Monkey]

Thanks to the AliExpress sale I picked up a fresh pair of Deva Pros for only $164.

Two years ago or so I bought the Deva Pro as open box and wired only at the Hifiman site. I’d intended to buy a Bluemini R2R to go with it but Hifiman charges over $250 for it as a stand alone device and the lowest I’ve seen it new is $220 on sale. Not a great deal. Obviously Hifiman only wants you to buy the Bluemini R2R with one of the compatible headphones.

So at $164 it was a good deal to get the Bluemini R2R and a fresh pair of the Deva Pros. Weirdly this newer set has better fit due to stronger clamp force. I doubt they’ve updated anything about these and they probably only ever made one run of them, so I’ll chalk it up to the vagaries of loose design tolerances.

Regardless, the Bluemini R2R is pretty sweet. It’s on the warm side of neutral and (obviously) pairs well with the Deva Pro.

 

[TheFritz]

Just as brief information for those who may encounter the same problem wit their Bluemini R2R I had:
I dropped an older Bluemini R2R and there was something loose inside. It still connected by Bluetooth to the host but there was no sound signal coming from them - including no on/off messages. I opened them (simply carefully separate the two halves at the seams) and the R2R sub-board was disconnected from the main board:

I could simply re-connect the DAC sub-board with the connectors on the right and it worked again. The two halves of the case also snapped together without problem.
Super simple and only a bit annoying that the sub-bord is not connected more securely. And yes, it is fully balanced - in case you are still wondering.

As a side-note:
I have 4 of the Bluemini R2Rs salvaged from two Hifiman Deva PROs, one R9 and one R10d (all wireless) - mostly bought those headphones used "for parts" or as "acceptable" only to get the Bluemini R2Rs for (much) cheaper than buying them directly. I actually use the Bluemini R2Rs with other headphones where I soldered 4 pol TRRS 3.5mm sockets into the cups and re-wired them internally for balanced use (not only for Bluemini R2Rs but also simply to allow TRS SE and 3.5mm TRRS-to-4.4mm TRRRS balanced cable connections to amps). Specifically love the sound of the R2Rs with my DT1990pro and Sony MDRs CD900STs wireless.
Yeah, that is a bit exotic and nerdy, but if you ever feel like tinkering with your Bluemini R2Rs and headphones, I can recommend to try it out.

 

[Peddler]

I recently purchased the Hifiman Deva Pro's and I have to say I'm very impressed with both the headphones and the Bluemini. I really can't tell the difference between the Bluemini and my Fiio BTR7 (wired) - except of course the additional volume steps you get from the Fiio. Review to come.

 

[ultrarunner2018]

I just discovered something interesting about the Deva Pro and the R2R Blue Mini.
I like the sound of the Deva Pro using the Bluemini in BT mode from my Windows PC better than having the cans wired to my Schiit Modius/Magnius.
Normally, I use the Schiit stack with a pair of Senn HD-600's and they sound great - especially when I want to listen loud.
With the Deva Pro, I get more highs and the sound seems clearer when using the Bluemini Bluetooth than when I plug the headphones into the Schiit Magnius single-ended jack using the supplied cable.
The Senn HD-600's on the other hand are wired as balanced and plugged into the XLR jack on the Magnius.
It may be the balanced vs single, or maybe the impedance of the Magnius is a better match to the HD-600's 300 ohms vs the Deva Pro 18 ohms.
I guess I should re-wire the Deva Pro's cable or build a cable for balanced.

I tried to use the Bluemini as a USB DAC, but Windows didn't recognize it. There is probably a way to get this to happen, but I didn't feel like getting into that at the time.

 

[Dazerdoreal]

Yes, you lose a bit of low end using the Bluemini. This is a phenomena many devices with optional bluetooth have.
It is usually not wanted, but in case of the Deva is it helpful on certain tracks. Maybe this is the reason why the Deva is less bright than most Hifiman devices when used with a standard cable.

By the way, you also lose upper treble extension if you use the Bluemini. This is not so bad though because it would be piercing otherwise, without the low end to balance it out.

 

[znthem]

Just as brief information for those who may encounter the same problem wit their Bluemini R2R I had:
I dropped an older Bluemini R2R and there was something loose inside. It still connected by Bluetooth to the host but there was no sound signal coming from them - including no on/off messages. I opened them (simply carefully separate the two halves at the seams) and the R2R sub-board was disconnected from the main board:





I could simply re-connect the DAC sub-board with the connectors on the right and it worked again. The two halves of the case also snapped together without problem.
Super simple and only a bit annoying that the sub-bord is not connected more securely. And yes, it is fully balanced - in case you are still wondering.

As a side-note:
I have 4 of the Bluemini R2Rs salvaged from two Hifiman Deva PROs, one R9 and one R10d (all wireless) - mostly bought those headphones used "for parts" or as "acceptable" only to get the Bluemini R2Rs for (much) cheaper than buying them directly. I actually use the Bluemini R2Rs with other headphones where I soldered 4 pol TRRS 3.5mm sockets into the cups and re-wired them internally for balanced use (not only for Bluemini R2Rs but also simply to allow TRS SE and 3.5mm TRRS-to-4.4mm TRRRS balanced cable connections to amps). Specifically love the sound of the R2Rs with my DT1990pro and Sony MDRs CD900STs wireless.
Yeah, that is a bit exotic and nerdy, but if you ever feel like tinkering with your Bluemini R2Rs and headphones, I can recommend to try it out.

Hi, I'd like to ask what is the specification of the battery inside, my hifiman bluemini has been used for a long time, I feel seriously aging, want to replace the suitable battery， thank u