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Douk VU2 Review (VU Meter/Input Selector)

amirm

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This is a review and detailed measurements of the Little Bear / Douk VU2 input selector and VU meter. It was kindly purchased new by a member and drop shipped to me. VU2 costs US $189 from Amazon including Prime shipping.

The main attraction here are the VU meters and Douk delivers with two large sized ones:

Little Ber Switcher Sound Level Indicator VU2 Review.jpg


When turned on it lights up with the standard yellow glow. Alas, it only lights up the middle third and nothing like the uniform yellow their advertising shows. A horizontal bulb that covers 1/4 of the meter provides lighting with no diffuser (it is diffused itself).

The rear labeling is confusing:
Little Ber Switcher Sound Level Indicator VU2 Review Inputs.jpg


How could one channel be in, and the other out? Then I realized it is bi-directional and can form 4 to 1 or 1 to 4. At least I think that is how it works.

More confusing are the front panel controls. They do NOT operate on the signal itself but the action of the meter. Delay is not delay but filtering of the VU meter. All the way to the left is "fast" and to the right, slow. I say "fast" in quotation mark because typical of these meters, it is slow to begin with. Still, nice to have the control.

The gain control is again for the meters. This is essential in my view to get reasonable movement out of them. And nicely so, there is AGC (automatic gain control) so it can optimize the movement for you.

In use, I found the Gain control and output to be quite erratic. At some settings of gain the meter with a steady signal would jitter back and forth. Strangely, even the green LED above it would do the same! The gain setting was also not linear. I got most of the range from minimum to just hair above. Then the output would strangely drop. I could not make any sense out of it.

In case you are wondering, that USB connection is for power. They give you a USB cable but no power supply. At this price, I expect one included. I used a high power one I have for RPi computer boards.

Little Bear Douk VU2 Measurements
I treated the unit like a pre-amp and fed it 2 volts and got this:

Little Ber Switcher Sound Level Indicator VU2 Measurements.png


Oh boy. I expected a simple pass through link so did not at all expect distortion let alone at this very high level.

I suspected that the input stage of this thing is loading down the AP. So I put the AP in loopback mode meaning it is measuring itself. With nothing connected to AP, I would get SINAD of 121 dB+. But the moment I connected the output of the AP to VU2, I got this:


Little Ber Switcher Sound Level Indicator VU2 Measurements loopback.png


In other words, the VU2 is severely loading down the AP output causing such significant amount of distortion!

So not only can't you use this as a switcher, but you can't use a wired connection to sample your audio as that distorts that source. Maybe you have a buffered output in your pre-amp or something but if you don't, watch out.

Fortunately this thing also has a Microphone that can sample the audio that way. I did not measure this but just turning it on and tapping on it and such, it seemed to produce a movement on the VU meter.

Conclusion
Ah, what a missed opportunity to build a decent VU meter. :( I remember building a blinking disco light to the tune of music when I was 10 years old and it too distorted the heck out of the input when connected. I was concerned that this thing would do the same and it does. Its input needs to be buffered and high impedance to avoid this.

Sadly, as much as I love VU meters, I can't recommend the Douk VU2. It is just too broken.

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As always, questions, comments, recommendations, etc. are welcome.

Any donations are much appreciated using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

polmuaddib

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So there is absolutely nothing going for this product. Ugly, not functional and broken performance. Disassembled and sold for parts, I say.
 

Joachim Herbert

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Schade!
 

wwenze

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Hmm... adjustable meter "speed"

I've never used analog VU meter, was born in the digital age so the digital meters have peak hold and etc features. So here's a question out of curiosity - Is there a "standard" for the "speed" of these meters?
 

dougi

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Hmm... adjustable meter "speed"

I've never used analog VU meter, was born in the digital age so the digital meters have peak hold and etc features. So here's a question out of curiosity - Is there a "standard" for the "speed" of these meters?
Yes there is a standard rise time, reg level etc, that was used in broadcasting etc until the digital age. Just see the Wiki page for VU meter for an introduction. Given this meter's adjustability, it would probably be difficult to set it to the standard.
 

iMickey503

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Hmmm. This is going to have to make me take a second look at the LED VU meter I have. I get these things not for monitoring, but like most people, (Technomoan) I'm in it cus I like to see the visualization aspect of the music.

I'm getting more leery as time goes on about messing with anything in my analog signal chain.

As far as the Microphone input for VU meters? I'm fine with that as long as its just for show. the circuit has been around since the old velleman kits from what I understand. Meters like this with the microphone built-in are basically just for Aesthetics since the microphone placement is far away from the listening area.


As far as the aesthetics? it seems to have a very industrial consumer design language something that is meant to be an appliance but absolutely functional but not a joy to use. in essence, the design reminds me of a light switch and is just as forgettable. I really miss the design language that they used to use in the 20s 30s and 40s even in the 50s when things got really wild in consumer electronics.

a device like this is made to be looked at. it's a shame they don't put more into the visual Aesthetics of products whose sole purpose is to be looked at. I understand that beauty is in the eye of the beholder but I don't find this unit particularly wonderful to display. it's like steampunk but without the Steam and missing the punk.

with all the choices and fonts that are out there you think they do something different with the Meters? I really like the old industrial look of meter's they use at Power stations an electrical plants of old. even with age, they have a really nice patina. even the glass that they used had a certain round to it so it played well with the light and made a interesting visual distortion of the needle and background having more depth like a clock face.

if someone who designs Fashion watches was hired on to design the face of a piece of equipment like this I think it would be a rather amazing device that a company probably couldn't keep on the shelves for very long. it would also appeal to a much wider audience while still being economically feasible to produce and meet price point market targets.

the unit looks well put together. it just doesn't have any Zing. That's kind of important for a Consumer VU meter. However, there are folks that like the utilitarian design language and might go well with their setup. Its just not my taste.
 

Count Arthur

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$750 is quite a step up in price though. :oops:

Regarding the VU2, am I to understand that even if not in-line, these might have a negative impact? For example, on the back of my DAC there are both balanced and single ended outputs, which can be used in parallel.

Also, just for fun, I came across these on Amazon: https://smile.amazon.co.uk/Meters-C...d78ec8&pd_rd_wg=5kg11&pd_rd_i=B085LK65N7&th=1

1631527154292.png


Surely the most pointless VU meters ever, unless you have eyes on stalks, like a snail perhaps. :facepalm:
 

Hayabusa

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from their website:

Notice:

1. 4 channel can work (input or output) at the same time, but this function only can be set by pressing the four channel buttons on the front panel, cannot be controlled by remote control.

2. When in 4-IN-1-OUT mode, 4 channels of VU2 are not recommended to work in parallel, there will be some distortion if the output level of 4 players are different.

3. Not recommend to power VU2 from the USB interface of audio source device, noise will be generated in this condition.

@amirm Could it be some it was configured in such a way that two outputs were connected to each other? It could explain the distortion/
 

IVX

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View attachment 153074

Surely the most pointless VU meters ever, unless you have eyes on stalks, like a snail perhaps. :facepalm:
Haha, I love VU meters anyway )) I made one on LCD+STM32F03+radio button "Calibration"(any input voltage from .5 to 50V will be set as a 0db) only add 3.3V power. I agree it is stupid to love old-style UV meters but I do ))
 
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pma

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I suspected that the input stage of this thing is loading down the AP. So I put the AP in loopback mode meaning it is measuring itself. With nothing connected to AP, I would get SINAD of 121 dB+. But the moment I connected the output of the AP to VU2, I got this:

Might be working without distortion only from low-impedance sources like output of the power amplifier. Don't you have one somewhere to try it?
 

Timbo2

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I struggled to find a picture of the inside of the unit. This was the best I could find. Plenty of relays!

81oEWIZTJ9S._AC_SL1500_.jpg
 
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