Douk VU3 VU Meter Review (Updated Version)

[sarumbear]

OK, this may be ignorant, so feel free to mock me, but...what do you do with this thing? Watch the needles quiver?

It satisfies the number one reason (as listed) for ASR's raison-d'etre.

WANTED: Happy members who like to discuss audio and other topics related to our interest.

 

[fpitas]

It satisfies the number one reason (as listed) for ASR's raison-d'etre.

WANTED: Happy members who like to discuss audio and other topics related to our interest.

I wouldn't dream of depriving someone.

 

[thecheapseats]

View attachment 284657

those LEDs certainly lite up those VU meters - much better color and brightness than the bulbs from back in the day...
great fabrication job...

 

[NoxMorbis]

SINAD is just 1kHz tone (at a certain specified level) in relation to all 'crap' levels that should not be there converted to dB and the dB naming and sign removed.
You cannot simply 'add' dBs in this case. They represent level differences.
You need to convert dB's to linear levels, add the levels and then convert back to dB.
110 is 3x higher in level than 120.
100 is 10x higher in level than 120
80 is 100x higher in level than 120
We have to add levels. The levels are very, very, very small and below any audible threshold levels.
Even SINAD 80 (depending on the harmonic spread) is probably only audible in lab conditions with extremely good speakers/headphones, trained listening to pure tones.
When you add very, very, small amounts of levels to 100x higher levels this is not going to be audible nor really visible in numbers and impossible to hear as the relatively massive amounts of 'unwanted crap) are 'masking (overwhelming)' the minute added crap.
With music, being dynamic in nature and signals masking other signals you really cannot detect crap that is even louder than the music unless it is constant in level (say noise, hum, or other constant noises). Distortion levels, however, go up and down determined by the actual levels and harmonics in the music will mask those tiny, tiny levels anyway.
For this reason it matters if we are looking at distortion while considering music. It is not the same as test tones as all kinds of perception aspects is going on.

Thanks for hanging in there with me. I knew the calculation was something like magnitudes. So, if I understand, It's not as if SINAD stacks on top of each other, like you explained. A lower SINAD is so noisey that using a peice of equipment with a higher (less noisy) SINAD is not audible? Is that the concept?

 

[NoxMorbis]

For those who need meters…this one is about a square meter.

Found this free app Kauna. I hdmi my computer to the tv and usb the sound to the dac. No interference
View attachment 284508

Yeah, but does it have a back light?

 

[solderdude]

Noise is not the same as distortion.
In most cases SINAD (being distortion + noise) is dominated by distortion products.

Noise is not signal related and is constant so audible when the music (and distortion products) are low in level.
Added harmonics AND InterModulation products are not constantly present and are signal dependent.

 

[NoxMorbis]

You mean... it is a box with 2 meters in it that have 'VU' written on them and have a typical 'VU scale' which appears to not even indicate dB's correctly.

Yeah, MAN, that's what he said: A VU METER! Come on!

 

[NoxMorbis]

Yes,
and/or switch between amps and or speakers, possible even using a remote.

LOL, now, someone gets it.

 

[solderdude]

A VU meter should show Volume Units.
It should show the correct ones, so -10dB opposite 0dB should show -10dB. It does not even do that. It is 'approximate' at best.
It should be referenced (well, 0dB should be) and it isn't.
This means it isn't a VU meter. It is a meter with a VU scale. The needles just dance around to the music indicating nothing really.

 

[NoxMorbis]

I have a reply from Douk. At least they aren't trying to hide it, but they should have fixed it is they are calling this an 'updated' version, since it isn't as far as noise and distortion:

"From the post, the influence would be severer with higher power. Our initial estimate is that it should be caused by the isolation transformer that comes with the VU3. We need to do some tests to determine this problem, if so, we will consider using a special chip to detect the amplifier current in the future." Best Regards Yours Douk Audio

 

[solderdude]

LOL... they should look into the transformer (the non linearities it brings most likely saturation) AND the used relays (that aren't really suited for the task)
Both things add to the added distortion. This much is clear from Amir measurements and follow-up measurements.

As said... it is a NON issue, not even worth investigating further as it is far below any audible limits and it is just a toy... eye-candy basically, not a serious tool.
Nice looking though and the remote control AB possibility is nice/handy.

 

[Laniciffo]

As is now this is just eyecandy and not a measurement device. Swinging needles for the sake of looking at 'swinging needles looking pretty''

Eye candy to go along with ear candy : music !

 

[NoxMorbis]

As said... it is a NON issue, not even worth investigating further as it is far below any audible limits and it is just a toy... eye-candy basically, not a serious tool.
Nice looking though and the remote control AB possibility is nice/handy.

What does it mean then when Amir says it's "ok if amp SINAD is <92"? What if the amp is 100?

 

[amirm]

What does it mean then when Amir says it's "ok if amp SINAD is <92"? What if the amp is 100?

I deleted that because @solderdude made a good point that it likely reduces performance of most amps. Indeed when I had binding post issues, it caused degradation in lower SINAD amps just as well.

 

[NoxMorbis]

I deleted that because @solderdude made a good point that it likely reduces performance of most amps. Indeed when I had binding post issues, it caused degradation in lower SINAD amps just as well.

Now I'm really confused because how I took Solderdude's comment was that if the amp is lower SINAD than the VU meter, it doesn't make the amp's SINAD worse. (The 92 SINAD comment is still on the graphic!!)

 

[amirm]

Now I'm really confused because how I took Solderdude's comment was that if the amp is lower SINAD than the VU meter, it doesn't make the amp's SINAD worse. (The 92 SINAD comment is still on the graphic!!)

I am going by the test with the relays/switchers being in the loop. Whether the parallel wiring scheme does that or not, I don't know as I have not measured that impact elsewhere.

 

[NoxMorbis]

I am going by the test with the relays/switchers being in the loop. Whether the parallel wiring scheme does that or not, I don't know as I have not measured that impact elsewhere.

I think Sodlerdude is also using the entire test, not the parallel test? How I take his comment is that anything with a SINAD lower the the VU meter is inaudible . . ."so it's a nonissue."

 

[amirm]

I think Sodlerdude is also using the entire test, not the parallel test? How I take his comment is that anything with a SINAD lower the the VU meter is inaudible . . ."so it's a nonissue."

Inaudible is different than what is measured. I thought we were speaking of the latter. Inaudibility is a guess. From my point of view, if you are buying a very well measuring amplifier, you want to preserve that performance and not route it through this meter. Bling is good but no reason to leave performance on the table. Ultimately the right meter is a line level one anyway.

 

[AdamG]

Inaudible is different than what is measured. I thought we were speaking of the latter. Inaudibility is a guess. From my point of view, if you are buying a very well measuring amplifier, you want to preserve that performance and not route it through this meter. Bling is good but no reason to leave performance on the table. Ultimately the right meter is a line level one anyway.

A little birdy told me that the line level unit might be getting tested in the near future. If it tests well enough @Rick Sykora may want to send it to you for final testing. This something you might be interested in Sir?

 

[amirm]

Sure.