Douk VU3 VU Meter Review (Updated Version)

[Laniciffo]

A and B are in parallel, so you could leave your main speakers wired as usual on the A terminals and use short dedicated wires from the B output to the vu-meter.
That way the audio performances should be unchanged (the vu-meter is a negligible load for a speaker amp).
You just lose the switching function of the Douk device.
And you could even measure the effect of this load as disconnecting it using the amp's B switch would be very practical for an A (speakers) / B (speakers + vu-meter) comparison.
And for quiet dark listening sessions it would be easy to disable the whole vu-meter parallel chain.


Makes me think that, if the consumption of the electronics is low enough, one might even power the whole thing with the 12V trigger output of one amp. For example with an AVR you can select per input if the 12v trigger should be powered or not. My Denon can supply 12v / 150mA, 1.8W. Could be just enough with the 12v to 5v down-converter and the vu drivers + leds. It would be safe though to disable the internal relays to limit power.

 

[amirm]

Makes me think that, if the consumption of the electronics is low enough, one might even power the whole thing with the 12V trigger output of one amp. For example with an AVR you can select per input if the 12v trigger should be powered or not. My Denon can supply 12v / 150mA, 1.8W. Could be just enough with the 12v to 5v down-converter and the vu drivers + leds. It would be safe though to disable the internal relays to limit power.

I haven't measured it but the manual says 1 amp for the 5 volt supply. I should check but I think the bulbs are the old fashioned kind, not LED.

 

[danielbaen]

Hello, I have this product and when an infrared signal (from any remote control) reaches it, the light from the voltmeters dims
Does it also happen in your unit?

 

[Laniciffo]

The 100 W limit probably comes from the wiring+relay amp limits and from the max supported input voltage.
With the parallel route there is most likely only very little current flowing though the device and, if you really need a lot of power (and voltage) to drive your speakers, you could add a simple voltage divider at the input of the vu-meter. One single resistor might even suffice if carefully chosen.
With the parallel solution you can probably make it support multi kW power if you will (depends on the input impedance).

 

[amirm]

Hello, I have this product and when an infrared signal (from any remote control) reaches it, the light from the voltmeters dims
Does it also happen in your unit?

I didn't think to test that! Need to go to bed now but will see if I can test that tomorrow....

 

[Laniciffo]

Yes, I'm really interested in this device hence my on-going reflection and 'great' rating !

If the 100 W limit is properly specified, the current limit should apply to 4 ohm speakers (5 A rms = sqrt(100/4)) and the voltage limit to 8 ohm speakers (28 V rms = sqrt(100*8)).
As the typical speakers are less than 8 ohm impedance, that voltage limit might never be reached.
For example, assuming there is no large current in the meter thanks to the parallel route and a hypothetical constant 4 ohm speaker impedance, the voltage limit is equivalent to a 200 W power limit into 4 ohm (28*28/4).

The concept of a speaker-level meter seems to me inherently better than line-level from the sound fidelity perspective as the speaker amplifier has such low output impedance.

Line-level has the benefit of being listening-level independent if sensed before the volume setting, but the low voltage and limited power exposes to the problems you noticed on the line-level Douk meter (excessive load leading to heavy distortion).

Besides, as I use an AVR and digital sources I do not have access to an analog line-level signal (recent AVRs do not have analog outputs to connect recorders).
I do have the pre-out signal, but at my usual listening levels the voltage is so low that it's hard to extract it well from the noise (tested with a graphic equalizer).
The zone 2 or 3 outputs do generally have line level, but are cumbersome to use (need to switch them on each time) and I don't even get a signal for all sources (ex : hdmi).

Speakers do get consistent signal levels however.
This vu-meter seems to be the best solution for me.

Thank you so much Amir for this review.
I've been eyeing this on Amazon for a while but your previous review of a Douk device scared me.

 

[enio nery]

silly question maybe. but cant you just run separate cables in parallel with your main speakers as to avoid the degradation?

 

[PeteL]

I think it's established now that VU for power amps have very little meaning on what it's measuring and I is not much more than eye candy. Now, It got to have some sort of calibration on what it's showing, we got to have some idea of what 0VU refers too. I mean, it has to be measuring something It got to have a reference level, There is a "swing range" control I get it means what it says, but then, what range, and what is the zero reference. There has been many of these reviews, I still have no Idea what it does. Now we may accept the fact that it's just for show, well ok, but it still shows something that should have a meaning. Does it measure volts? Then why not show "Volts" instead of VU You want to change the range? Why not have a switch that says X10 like on measuring equipment. That wouldn't be more expensive, that wouldn't look less cool, it already does all that but at least it would mean something. Universally, a "peak" indicator means clipping. There is a peak indicator. What does it shows? What does it tell us? Shouldn't that maybe be covered in a technical review?

At least, VU aside, this device actually have a purpose, it can switch speakers and switch amps.

 

[danielbaen]

I didn't think to test that! Need to go to bed now but will see if I can test that tomorrow....

Your conclusions in your reviews are exceptional and I take them extremely seriously when purchasing my devices. Thanks for everything, really

 

[Joachim Herbert]

Well they never ask before the fact. They only in rare cases listen and digest the information after.

 

[sarumbear]

Sorry to sound stupid but what do the meters measure? How are they calibrated?

And, why can’t you connect to your amplifier outputs in parallel, using a spur to the unit.

 

[tritopia]

I use a TC Electronic Clarity M Stereo for this purpose. Unbelievably cheap for what is, with huge flexibility. Can accept all spdif formats (toslink, rca coax, aes, bnc) and usb (only for in DAW work w/ plug-in.). Also 0db is actually 0db, since it’s digital.

Yes i agree!
I just wish they were implemented on a cheaper device at a more audiophile level.

 

[sarumbear]

Yes i agree!
I just wish they were implemented on a cheaper device at a more audiophile level.

I use one and I don’t see US$350 as very expensive among the many devices we use in our systems. For an extra $200 you get a calibrated device that measures the audio loudness and frequency spectrum. I’m waiting @amirm’s reply but all I see it a gimmick; the meters are not cali rated hence they do not measure anything.

 

[AdamG]

I like to see Douk produce a version of this with RCA input (and pass through).

They do actually:

Douk Audio VU2 MIC+LINE Dual Analog VU Meter Stereo RCA Audio Splitter Switcher Box Audio Spectrum Display

Warm Tips Compatible with most audio devices, but cannot guarantee 100%. If there exists common ground noise, please add an isolation module between VU2 and your device. Features VU2 VU meter & audio splitter box is originally designed by Douk Audio: As an analog VU meter, with wired stereo RCA...

doukaudio.com

 

[Rottmannash]

I have a need for such a device, as I sometimes want to listen to my TT which is hooked to an old NAD 3140 but it's a headache switching the speaker cables from the main system and the NAD. Is there a better quality/measuring unit I could look into? I00 watts won't work for the main system (Purifi's).

 

[AdamG]

I have a need for such a device, as I sometimes want to listen to my TT which is hooked to an old NAD 3140 but it's a headache switching the speaker cables from the main system and the NAD. Is there a better quality/measuring unit I could look into? I00 watts won't work for the main system (Purifi's).

At first glance the RCA input version of the VU Meter unit does not seem to mention any voltage limit. Have it drop shipped to Amir Win/win

 

[JDS]

This is a review and detailed measurements of the Douk Audio (Little Bear) VU3 VU meter and amplifier/speaker selector. It was kindly drop shipped to me by a member and costs US $139.
View attachment 283799
Both the case and the VU meters are top class. The metal box is heavy as to help keep it in place and the glass in front of the VU meters ultra clear. Picture above is a bit washed out relative to the smooth/vintage shading of the yellow color. The peak LED is an added bonus. Sensitivity control is smooth and nice to operate. The two selector switches activate what sounds like hefty relays providing some sense of quality.

The back panel is where the problem is *for me*:
View attachment 283800

I don't want to route heavy/messy speaker cables through this just to have a VU meter. I rather have a line level one. But maybe your needs are different.

As you see power input is a USB-C jack but no supply is provided. I used a Samsung phone charger which worked well.

I first used whatever speaker cable I had to put the unit inline with my amplifier but that caused measurements to drop. So I built 1 foot bare wire speaker cables which worked better than any off-the-shelf banana cable.

Douk VU3 Measurements
The unit is rated at 100 watts maximum so I used a Topping LA90 as the amplifier. Here is the fresh measurements of that by itself:
View attachment 283801

Superb performance as before. Now let's route it through VU3:
View attachment 283802

We have fair bit of increase in distortion. Note that testing amplifiers at this level of distortion requires absolute attention to speaker wiring and termination. So likely the cabling had some contribution but it is impossible to separate that out. Let's put a pin in this for now and test SNR:

View attachment 283803

That's good. We have transparency there as well as in crosstalk:
View attachment 283804

Now let's sweep into 4 ohm and see what the difference is:
View attachment 283805

We see an increase in distortion with increasing power. As I noted, this can happen with less than optimal wiring. I checked my standard testing cables and they were sold. And as noted, I also made very short jumpers to connect the LA90 to VU3. My sense is that there may be some contribution for additional cabling. Most of this though is likely due to quality of the switching and speaker terminals in VU3.

All is not lost though. As long as your amplifier's SINAD is 10 dB or so worse than this number, you are OK. Here, SINAD is better than 100 dB so as long as your amplifier SINAD is no better than 90 or so dB, you won't notice an impact.

Conclusions
Douk nails the look and feel of the VU3. In addition, it doesn't have any of the horrendous loading problems of their other (line level) VU meters. Alas, the product is now inline with higher power speaker connection. With it, comes the limit of 100 watts and potential for degrading amplifier performance at higher power levels. I like VU meters but don't want to give up hard earned transparency in the amplifier I paid for. I like to see Douk produce a version of this with RCA input (and pass through).

As it is, the Douk VU3 is not for me. Your priorities may be different so you can decide otherwise.

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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/

I'm old enough to have a bit of nostalgia for VU meters, too -- from tape decks and from a Son of Ampzilla I had way back when. But for me there is a fundamental shortcoming to all of these external VU boxes: setting the levels.

I assume the meters on my ancient amp were calibrated so that 0db was set to equal max output before clipping. How is Joe Consumer supposed to calibrate these meters without test equipment (and without endangering speakers and/or hearing)? Absent such dialing in, aren't these just decorative toys?

 

[mgbpuff]

Why another review? You reviewed this September 24. 2021.

 

[Ken Tajalli]

P.S. It is "spring break" vacation time for the panthers and hence the reason there is none in the review picture....

Have you sent them off to the coronation to swear their allegiance in person?

 

[wwenze]

Why another review? You reviewed this September 24. 2021.

Better amp this time to really showcase the higher distortion