Douk VU3 VU Meter Review (Updated Version)

[dualazmak]

A little birdy told me that the line level unit might be getting tested in the near future.

Is the line level unit you are referring fully compatible with IEC 60268-17 VU meter specification/standard?

If not, I assume we should carefully avoid the wording "VU meter" for it; maybe "quasi-VU" or "pseudo-VU" or "sham-VU" would be suitable.

 

[Rick Sykora]

Sure.

Will PM you with a proposal.

 

[dualazmak]

Just for our reference,,,

In Japan, Yamaki Electric Co., Ltd. is still on business of professional use VU monitors and VU meters;
https://www.yamaki-ec.co.jp/product_cat/vu-monitor/
https://www.yamaki-ec.co.jp/product_cat/vu-meter/

I actually saw some broadcasting studios and recording studios are using Yamaki's VU monitors, like this TV screen capture showing Yamaki VUM-A208;

 

[Robbo99999]

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!!)

My understanding of the conversation and theory is that the higher the SINAD of the amp the more SINAD numbers you lose vs if the VU3 was connected to a low SINAD amp. Connecting the VU3 to a higher SINAD amp is theoretically giving you a better overall experience than if you connect it to a lower SINAD amp as the combined SINAD number is still higher with the high SINAD amp. But really, the thinking behind this is that those that have bothered to purchase a high SINAD amp wouldn't be connecting it up to the VU3 because if they're that worried about SINAD they wouldn't want to lower it by using the VU3. Also it's possible that the people who are purchasing the high SINAD amp are using it with other high quality components such as top notch speakers or headphones in properly setup rooms where it perhaps becomes marginally more likely that the VU3 inclusion could become a borderline noticeable detraction to the quality of the sound......I can't qualify this last statement though. Point is, if there were better VU meters out there that didn't reduce SINAD, (as well as actually being a proper VU meter in the first place!) then you wouldn't be buying the one in this review (cost not taken into account).

 

[NoxMorbis]

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.

It would be informative to have two conclusions, one the measurement, and two audibility. And then when we discuss the product, make sure we make clear which we are talking about. I know I would find that informative when making decisions!

 

[NoxMorbis]

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?

Which one! Post link please!

 

[NoxMorbis]

Is the line level unit you are referring fully compatible with IEC 60268-17 VU meter specification/standard?

If not, I assume we should carefully avoid the wording "VU meter" for it; maybe "quasi-VU" or "pseudo-VU" or "sham-VU" would be suitable.

You're not wrong!

 

[amirm]

It would be informative to have two conclusions, one the measurement, and two audibility.

Informative yes. Feasible, no. Whether some impairment is audible depends on huge number of factors from listener skills to nature of distortion and even type of content you listen to. There does come a point where regardless of these, the device is transparent. That occurs at SINAD of around 115 dB. Anything else becomes a gray area.

 

[NoxMorbis]

My understanding of the conversation and theory is that the higher the SINAD of the amp the more SINAD numbers you lose vs if the VU3 was connected to a low SINAD amp. Connecting the VU3 to a higher SINAD amp is theoretically giving you a better overall experience than if you connect it to a lower SINAD amp as the combined SINAD number is still higher with the high SINAD amp. But really, the thinking behind this is that those that have bothered to purchase a high SINAD amp wouldn't be connecting it up to the VU3 because if they're that worried about SINAD they wouldn't want to lower it by using the VU3. Also it's possible that the people who are purchasing the high SINAD amp are using it with other high quality components such as top notch speakers or headphones in properly setup rooms where it perhaps becomes marginally more likely that the VU3 inclusion could become a borderline noticeable detraction to the quality of the sound......I can't qualify this last statement though. Point is, if there were better VU meters out there that didn't reduce SINAD, (as well as actually being a proper VU meter in the first place!) then you wouldn't be buying the one in this review (cost not taken into account).

I understand that! 106 SINAD is till excellent, but I understand people who are not okay pulling down their 120 SINAD amp to 106. I get that completely.

 

[NoxMorbis]

Informative yes. Feasible, no. Whether some impairment is audible depends on huge number of factors from listener skills to nature of distortion and even type of content you listen to. There does come a point where regardless of these, the device is transparent. That occurs at SINAD of around 115 dB. Anything else becomes a gray area.

In formative in the sense that someone with a 92 SINAD amp who would want that switch box would understand that for their purpose, they would not hear any difference between the amp and speakers with the box in the middle.

 

[solderdude]

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.

Yep signal fidelity is not the same inaudibility. When you buy gear with the intend to get the ultimate in signal fidelity you should not use extra binding posts, relay or extra switch contacts, very thin lamp-cord as speaker cables over long lengths. Those things can degrade what one wanted to buy. It technically does not matter if any of this may reach audible levels and even if it does whether one likes it or not. It stands in the way of the objective (signal fidelity).

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."

I looked at all tests.

If one wants to really monitor something it should at least be relevant to what is monitored. The VU3 cannot do that unless you calibrate it somehow and even that does not seem really possible. It shows a swinging needle. Fine if that's what someone wants.

If I were forced to use these exact meters and make them actually monitor an amp (so make a useful device out of a toy) and would need to preserve signal fidelity there are 2 ways I would go about it and keep signal fidelity impact (audible or not) the lowest.

In case I only had one amp that is to be used I would use it in parallel (so not using the switch function)
I would try to determine (by using a constant signal) at which level the 'peak monitor' goes on.
I would try to find out at which level the amp (with load) starts to clip.
Then set the sensitivity of the VU3 to max level.
Mount a variable resistor in series with the input of the device and set the resistance so that the peak-light comes on about 1dB before clipping level.
That extra resistor will certainly help lower the 'measured increase in distortion' (which is also amp output Z dependent).

Or... even better:
I would use 2 amps. The 'good' amp driving the speakers, a cheap speaker amp to drive the meter, essentially turning it into a line level meter.
Split the line-level after the volume control.
Use speaker amp as normal.
Connect meter to cheapy, set the meter to max. sensitivity. Use the volume control of the cheap amp to calibrate the meter (to line level or max. output level of the speaker amp.

That said. If you have anything but a high-end listening setup and want to see some swinging needles and really like the looks or need the extra functionality then you can use it as it is intended and it will have no sonic impact. There will be a small 'modification' to the signal though. When this would be nagging in the back of your mind you should not use it. If it had not been measured by Amir you would not have known and it would not have nagged in the back of your mind as you would not hear an impact and would have happily switched amps and speakers and enjoyed swinging needles and blinking LEDs and played around with the remote.

In formative in the sense that someone with a 92 SINAD amp who would want that switch box would understand that for their purpose, they would not hear any difference between the amp and speakers with the box in the middle.

Also not with high SINAD amps. It could only be measured.
Added distortion products to become audible they must exceed an audible threshold.
So... you would have to play peaks of 120dB SPL in your room (which is impressively loud and not many can reach in living rooms) and then distortion products could reach the absolute silence levels in your room.
At the exact same time there are thus extremely faint sounds, one would barely be able to hear when no sound is present, and at the same time have super loud sounds playing that are near deafening levels. Also these sounds are related so only present at the exact same moment. It is not like a noise floor or a constant low level sound.

 

[JakeK]

I feel like the main purpose of this switch box with meters is being disregarded. I suppose that could be fair as the purpose of sharing speakers between 2 amps is not best practice for sound quality as it adds extra connections and cables between the amp and speakers which has a measurable effect even if it can be argued to have no audible difference. Not to mention the large amount of cable clutter such a setup adds behind your rack. Although the box is to all intents and purposes transparent in the audio chain there are better ways of enhancing your AV and hi-fi setup. There are also better ways of having a display with moving signal meters.

On the other hand I think everyone should try A/B listening tests at home and this device enables that for a reasonably low cost. I can't emphasise enough how useful and enlightening that can be as a consumer of home hi-fi. Are there better devices out there for similar money for this purpose? Ignore the meters which seem to have little practical purpose apart from confirming the amp is outputting a signal.

 

[amirm]

I feel like the main purpose of this switch box with meters is being disregarded.

Members are buying them as just VU meters so that is how I am testing them.

 

[NoxMorbis]

Members are buying them as just VU meters so that is how I am testing them.

The reason I considered it was that the VU3 is 140 and the plain vanilla Doiuk VU box is 100. So for 40 bucks you get a switch box, and square VU-like meters. Sometimes I get Chinese speakers at the 100.00 USD level, give or take, for reviewing them as a listening test only. The switch box would be a nice touch. I also have a Douk and Aiyima older class D amps using the Ti 3116D2 chip. It would be just fun to switch them back and forth between the new 32xx chip amps and see if I can tell the difference (I doubt I can). I don't need absolute transparency to do those things, although it would always be nice.

 

[NoxMorbis]

Also not with high SINAD amps. It could only be measured. . . .Also these sounds are related so only present at the exact same moment. It is not like a noise floor or a constant low level sound.

THIS--> Also not with high SINAD amps. It could only be measured. . . .It is not like a noise floor or a constant low level sound.

Thank you for explaining it again in a different way!

 

[JakeK]

Members are buying them as just VU meters so that is how I am testing them.

The testing shows clearly that this isn't the best way to add a VU meter to your setup so that's useful, thanks!

 

[JakeK]

The reason I considered it was that the VU3 is 140 and the plain vanilla Doiuk VU box is 100. So for 40 bucks you get a switch box, and square VU-like meters. Sometimes I get Chinese speakers at the 100.00 USD level, give or take, for reviewing them as a listening test only. The switch box would be a nice touch. I also have a Douk and Aiyima older class D amps using the Ti 3116D2 chip. It would be just fun to switch them back and forth between the new 32xx chip amps and see if I can tell the difference (I doubt I can). I don't need absolute transparency to do those things, although it would always be nice.

This is exactly the sort of A/B testing more people should do for themselves. I'm not sure if this or the beresford switch I had in the past would be more effective for this. I think this Douk should be better but I've no ides if anyone has actually measured the beresford or if there is a similar switch that's better. Either way the more people buy these switches and compare amps and speakers themselves the better IMHO.

 

[NoxMorbis]

This is exactly the sort of A/B testing more people should do for themselves. I'm not sure if this or the beresford switch I had in the past would be more effective for this. I think this Douk should be better but I've no ides if anyone has actually measured the beresford or if there is a similar switch that's better. Either way the more people buy these switches and compare amps and speakers themselves the better IMHO.

At least both amps go through the same "noise" box when compared. lol Not really, since it's not even audible, but you get it.

 

[Oristo]

I checked my standard testing cables and they were sold.

I suppose that was intended to be "solid".

So, instead of straight wire with gain, these are instead crooked wires with distortion.

 

[NoxMorbis]

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?

No hint which one it is?