[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.