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Nobsound Little Bear Mc103 3-IN/1-OUT Measurements (XLR Line Switch/Selector)

VintageFlanker

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Nobsound Little Bear Mc103 3-IN/1-OUT XLR Measurements

Main.jpg


Hi folks,

Here is a quick measurements write-up of the Nobsound Little Bear Mc103 XLR line selector. This is the three inputs/one output configuration, pretty much similar to the "Pro" version @amirm reviewed a while ago. It has been kindly loaned to me by @Niconoclaste and costs 52€ as of this writing, but may be found cheaper depending on the location/store. It is by the way about 20€ cheaper than the MC103 Pro.​

Front.jpg


The Mc103 comes in a surprisingly robust case, with decent feeling considering the budget price. It is just heavy enough to remains stable and not be drawn by the weight of cables that are plugged in, which is nice. The selector knob is the only thing you will interact with.​

Back.jpg


As opposite the MC103 Pro, you got two inputs on the front and one on the back, which is a bit odd. Being a passive device, it obviously has no power switch nor plug.


Measurements

Disclaimer: Measurements you are about to see are not intended to be as precise or extensive than what you get from a 30k€ AP. There is obviously both hardware and software limitations here, so not quite apples to apples comparison with Amir's testing. Still, this data is enough to have a pretty good idea if the gear is bad or not, stellar, broken, or sub-par...

- ADC : E1DA Cosmos (Grade B). Minimum phase filter. Set to Mono Mode for REW and Stereo Mode for others tests.
- Software : RMAA 6.4.5 PRO and REW V5.20.7.
- Method : 8 runs for each test, then I choose the closest to the average. All regular tests are running 24bits / 44.1Khz.
- Due to its overall impressive performance, I used the Monolith Liquid Platinum I recently reviewed as a tone generator reference. The purpose is to find if there is any signal degradation by plugging the Mc103 between the source and the ADC. The balanced output of the Monolith is by the way measured at 4.25Vrms.


Let's start with a classic 1Khz "SINAD" FFT test. May we find any significant variation with or without the Mc103 in the signal path?...​

DAC Direct (Monolith Liquid Platinum)
Direct.jpg


Mc103 Input 1
THD+N 1.jpg


Mc103 Input 2
THD+N 2.jpg


Mc103 Input 3
THD+N 3.jpg

...No, we may not. Results are so identical that we are talking about less than 0.1dB variation of THD+N between each input. You may even see lower THD than the reference with Input 3, which is related to common run-to-run variations. Anyway, the Mc103 is absolutely 100% transparent in this testing.

Then, we still may try other tests, switching to Stereo Mode and RMAA:​

Summary

Test
Source direct (DAC)
Mc103 Input 1
Mc103 Input 2
Mc103 Input 3
Frequency response (from 40 Hz to 15 kHz), dB
+0.02, -0.02​
+0.02, -0.02​
+0.02, -0.02​
+0.02, -0.02​
Noise level, dBA
-124.5​
-124.2​
-124.4​
-124.3​
Dynamic range, dBA
124.1​
123.8​
124.0​
123.9​
THD, %
0.00004​
0.00004​
0.00004​
0.00004​
THD + Noise, dB (REW - Mono)
-119.9​
-119.9​
-119.9​
-119.9​
IMD + Noise, %
0.00033​
0.00033​
0.00033​
0.00033​
Stereo crosstalk, dB
-123.7
-117.0
-122.1​
-119.5​


Here we go. If Noise and Dynamic Range variations are two negligible to be considered, I've got constant and repeatable drop with crosstalk. I would have expected all three inputs to perform at least the same, but they are not. That being said, Mc103's crosstalk drop is honestly not "that" serious and it should stay audibly transparent. Looking closer at the graph, we see deviations occur from about 300Hz:
Stereo Crosstalk

ct.png

Frequency Response
fr.png

Noise Level
ns.png

Dynamic range

dr.png

THD + Noise (at -3 dB FS)
thd.png

Intermodulation distortion
imd.png


When measuring different inputs while running the 1Khz tone generator, I noticed a leak from one channel to the others (it occurs with each one of them, BTW). How "bad" is it?​

Mc103 Leak
THD+N Cross.jpg


Well, not that much. Basically, it is a -120dBFS signal... assuming one other input is feed by a 0dBFS one. While it could be audible in some case, for example if you crank up the volume of your amp and play no music signal into it, I cannot see any real-case scenario where this could be a problem.


Conclusions

Considering its low price, the Little Bear Mc103 gives you what you pay for : a transparent switch for your different source that just does its job. When looking at raw numbers, it is not technically "perfect" because of crosstalk variations and leak between inputs. Yet, you will be hard-pressed to be bother by these minor issues in real case usage. I give it my recommendation, but would personally spend a bit more for the pro version, as I prefer to have all connectivity in the back of my gears.​

Flanker rating: Competent
 
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Blumlein 88

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The larger Pro version doesn't have Neutrik XLR's. It also has a steel case and plastic front and rear panels. This one is aluminum on all sides. The larger one has twisted wire for most of the internal signal path, and this one has printed traces. Probably the twisted wire and greater spacing is why the larger one has less crosstalk. Neither has enough crosstalk to be a concern.

1654456327928.png


This is the one from this review.
1654456246148.png
 

renaudrenaud

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Thanks for the measurments... But, but, but... This is with the volume control full open. Maybe with 10% or 20% volume results are a bit diffrent.

Anyway for me this kind of box hat to be used full volume, but when starting up the system, especially with active spekaers, it give a way to avoid a disaster reducing the volume.
 
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VintageFlanker

VintageFlanker

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This is with the volume control full open. Maybe with 10% or 20% volume results are a bit diffrent.
Hi Renaud!;)
Not sure what you're are talking about, that's a switch, not a passive preamp. What difference could be expected with different voltage at input? Leak test probably, otherwise, I don't see any.
 

renaudrenaud

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Hi Renaud!;)
Not sure what you're are talking about, that's a switch, not a passive preamp. What difference could be expected with different voltage at input? Leak test probably, otherwise, I don't see any.
My mistake !

I've seen this 2 posts above:

index.php


And though it is a pot in the middle of the front face... Because of this model Nobsound Little Bear :

nobsound_little_bear_mc2_mini__1647844160_69b8dfa3


Now I've understood. Nobsound Little Bear is a general name and I have to pay attention at the end of the designation! :facepalm:


Mmm... I've finally unserstood : the MC103 is the box to add to a Topping A90.
 
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muslhead

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Thanks for this. Always wondered if passive really was passive and as such, had little impact on signal. While not perfect this is pretty good proof.
 

phoenixdogfan

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I have one of these too. I would also have preferred the professional model, but the one I have serves the purpose, so I'll just keep using it.
 

Acerun

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So I'm looking at a different version of the little bear that has both RCA and XLR.

Forgive me if I didn't see it or understand it in your review but I want to feed the little bear with XLR out from an RME ADI-2 DAC FS and I want that higher voltage from the XLR to pass through to the amp. Do we feel confident that happens?
 
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VintageFlanker

VintageFlanker

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I want to feed the little bear with XLR out from an RME ADI-2 DAC FS and I want that higher voltage from the XLR to pass through to the amp. Do we feel confident that happens?
I don't get it.

Do you actually need for an active preamp? A passive preamp, or an XLR switch (what I reviewed) ?
 

Acerun

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I need a switch, if the RME puts out seven volts into the little bear via XLR will 7 volts come out? That's really my question.
 
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Acerun

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Yes, if we are talking xlr to xlr. The Little Bear is just a switch. No volume, no buffering, no conversion to RCA.
So 7 volts in gives you 7 volts out? I saw the previous review that said 4 volts in and four volts out so just wanted to confirm because I want every single volt from that RME into my amplifier. ;-)
 

Blumlein 88

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So 7 volts in gives you 7 volts out? I saw the previous review that said 4 volts in and four volts out so just wanted to confirm because I want every single volt from that RME into my amplifier. ;-)
Yes, 7 volts, 10 volts whatever is input is also what you get output.
 
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