Douk VU3 Review (VU Meters)

[Doodski]

This is the amp that I bottomed out a Matrix 801 woofer and damaged it from so much power. It was thump, thump, thump, snaP>>. The M-03.

 

[restorer-john]

Luxman M-03 @ +/-81VDC rails and uses nice Sanken outputs on a decent heat sink.

Yep, and that's each channel.

 

[restorer-john]

This is the amp that I bottomed out a Matrix 801 woofer and damaged it from so much power.

Naughty boy. Run it in BTL if you really want to blow the doors off. They rate it at 450W/8R, but it's nearer 550W.

 

[restorer-john]

There's clearly pent up demand for meters such as the one reviewed here. Tandy/Radio Shack had various ones over the years, and I see they have skyrocketed in price.

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The moving coil large format meters seem to be either not available or all the same type of cheap Chinese meters. The days of high quality movements seems to be gone.

 

[pma]

Hall effect sensor or Rogowski coil. Yes not cheap. Request for cheap is a killer and produces toys only. As @restorer-john has mentioned, toys need no precision and can be made regardless parameters.

 

[solderdude]

I still don't get it why this device won't be good enough for people who just want swinging needle meters and why another one needs to be created from scratch. It already exists, looks nice is rather cheap and works fine.
Just don't run the speakers through the VU3.

Just connect the tested Douk VU3 in parallel to your speakers (at the amp side) and no need to look any further. There is no sound 'degradation' in this case and you are ready for $ 150.-
If I didn't already have meters (don't use them) I might even buy it.

 

[pma]

I still don't get it why this device won't be good enough for people who just want swinging needle meters and why another one needs to be created from scratch. It already exists, looks nice is rather cheap and works fine.
Just don't run the speakers through the VU3.

Just connect the tested Douk VU3 in parallel to your speakers (at the amp side) and no need to look any further. There is no sound 'degradation' in this case and you are ready for $ 150.-
If I didn't already have meters (don't use them) I might even buy it.

Yes but ….

1) the relays used are low current devices
2) small binding posts with close spacing do not allow me to use my big latching banana connectors that prevent from contact resistance issue.

So, even if I considered buying it re price, I would not because it is not practical to me.

I already have an experience with their 3 to 1 XLR switch. It works, however it is so small and low weight that it is unable to stay firm and not to turn over because of weight of XLRs and cables. Again not practical and finished in a garbage box. All these cheap purchases are in fact expensive.

 

[restorer-john]

It works, however it is so small and low weight that it is unable to stay firm and not to turn over because of weight of XLRs and cables. Again not practical and finished in a garbage box.

My test for garbage is simple. If you cannot plug or unplug a 1/4" headphone plug, RCA plug, or banana plug into the product without it moving (and without having to hold it still) it's just toy HiFi.

Anything you have to Blutak to the bench to stop the XLRs pulling it off the desk and onto the floor, is also a toy.

My little Focusrite 2i2 is cute, but it needs Blutak to hold the damn thing in place for even a 1/4" headphone being plugged in/out. I had to Blutak down my DSO on my bench, whereas a proper old-skool CRO doesn't move when you plug in BNCs.

 

[solderdude]

Yes but ….

1) the relays used are low current devices
2) small binding posts with close spacing do not allow me to use my big latching banana connectors that prevent from contact resistance issue.

So, even if I considered buying it re price, I would not because it is not practical to me.

I already have an experience with their 3 to 1 XLR switch. It works, however it is so small and low weight that it is unable to stay firm and not to turn over because of weight of XLRs and cables. Again not practical and finished in a garbage box. All these cheap purchases are in fact expensive.

These objections are completely irrelevant. That's the whole point I tried to make.
One connects some amp cord to the input (A or B doesn't matter) to the VU3.
Run that to the amp and parallel those wires to the speaker wires.
Done... meter works, no audible influence either.

If you cannot plug or unplug a 1/4" headphone plug, RCA plug, or banana plug into the product without it moving (and without having to hold it still) it's just toy HiFi

yep.. it is a toy. Some folks really love toys though.

Built myself a clipping indicator about 40 years ago.
Could set the meter in 1V increments (from 5V to 65V AC) and the LED blinked (0.1 sec). It was a more useful toy.

Had a scale on it that showed RMS voltage peak voltage and power (in 8 ohm).

10 years later built another (also useful) toy that showed the actual output voltage (well power in 8 ohm) with a dial on it that could set the clipping level of a connected amp, set to 120W in the pic below, this way you could see the (peak) power, with a slow return, and how far one is from the set clipping level.

Don't use either anymore.

 

[nagster]

Just connect the tested Douk VU3 in parallel to your speakers (at the amp side) and no need to look any further. There is no sound 'degradation' in this case

I hope it's okay, but in my experience, sometimes the sound goes wrong when connected in parallel. (Apart from volume reduction)
Douk seems to have occurred in VU2, so I'm also worried about VU3.

Douk VU2 Review (VU Meter/Input Selector)

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...

www.audiosciencereview.com

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:

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.

 

[nagster]

Oh, in the case of VU3, SINAD is only 3dB worse. I was exaggerated.

 

[Rick Sykora]

How about displaying the average and peak voltage on some 7-segment LED displays? Could even be in amber yellow, Amir's favourite colour. Maybe have it update twice a second or something.

Tom

Find lots of these on ebay and other sites. Rod Elloitt has this posted… https://sound-au.com/project60.htm

While I am fine with LEDs, most of the requests I get are for analog meters. There are inexpensive (unbalanced) driver boards for these too. Not sure how good they are, but usually based on TPA7318 or BA6138 chip.

Yes, many of these meters may be ”toys”, but many customers are just nostalgic and looking to set them to know when they are pushing amp to clip. Note the VU3 has a peak LED in the upper corner of the analog meter.

 

[Helicopter]

Find lots of these on ebay and other sites. Rod Elloitt has this posted… https://sound-au.com/project60.htm

While I am fine with LEDs, most of the requests I get are for analog meters. There are inexpensive (unbalanced) driver boards for these too. Not sure how good they are, but usually based on TPA7318 or BA6138 chip.

Yes, many of these meters may be ”toys”, but many customers are just nostalgic and looking to set them to know when they are pushing amp to clip. Note the VU3 has a peak LED in the upper corner of the analog meter.

Agree. Even if they are not precise, they can still be dialed in so 0dB provides useful information, and they are cool to look at. They can signal you might damage something, or they can signal you are going into high distortion / crap sound territory.

 

[pma]

The things like 2nd breakdown happen too quickly to be indicated by any needle.

 

[solderdude]

I hope it's okay, but in my experience, sometimes the sound goes wrong when connected in parallel.

It's no issue here. The only question is if the VU3 also can be used on balanced amps.

Oh, in the case of VU3, SINAD is only 3dB worse.

Not so when using it as explained.

 

[Rick Sykora]

On @Helicopter's amp, the VU meters are backlit by the Hypex clipping indicators. Here is an early pic without the front bezel and handles...

 

[Madjalapeno]

Find lots of these on ebay and other sites. Rod Elloitt has this posted… https://sound-au.com/project60.htm

While I am fine with LEDs, most of the requests I get are for analog meters. There are inexpensive (unbalanced) driver boards for these too. Not sure how good they are, but usually based on TPA7318 or BA6138 chip.

I was thinking about this set up from the same site - https://sound-au.com/project128.htm

 

[Helicopter]

On @Helicopter's amp, the VU meters are backlit by the Hypex clipping indicators. Here is an early pic without the front bezel and handles...

View attachment 155490

Ok, ok, here's the second attempt:

 

[restorer-john]

Ok, ok, here's the second attempt:

And the third attempt? Where you masked the meter window areas and painted the back of the perspex?

 

[Jimster480]

What is the purpose of these VU Meters anyway? I never understood why people like/want them other than for nostalgia?