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Douk VU3 Review (VU Meters)

restorer-john

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A door stop w/VU meters: To explain that to your better half, tell her that you are going to patent it:cool:!

She loves amplifiers with big power meters! And, yes, I have been known to hold a door open on a windy day with a random amplifer or sometimes just a transformer. Although stubbing your toes on a transformer at night is no fun.
 

JSmith

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This was posted in another thread somewhere, this case comes with VU's;


Hd9a8bca2db7747769441769fedaa4e6d5.jpg


H5a745d284d584a32bba042452c5da5a4G.jpg


An amp enclosure on eBay with VU's;


s-l500.jpg


Another;


s-l500.jpg


This is another ready to go from Douk Audio;

5dfc1eed29e7862dd222cc98-9-large.jpg



This has Power/Watt meters;


s-l1600.jpg




JSmith
 

restorer-john

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This has Power/Watt meters;

Clearly they don't understand dB in China. :facepalm::facepalm:

1632704696066.png


200W is +3dB. 400W would be +6dB
10W would be -10dB and 1.0W would be -20dB

Not only that, each order (x10) on the scale is log, not linear as they have done. It's useless. A pity.
 

pseudoid

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You showed me yours, now you are forcing me to show you mine (no zippers involved)!
202109_AimpVUmeters.jpg

This one is a freebie with most WinOS, MediaPlayers (some with a variety of 'skins').
 

solderdude

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The meter in the post above (when it were a physical one with the same usual scale) will only need rectification of the input signal to say something (0dB needs to be defined).

The examples above the previous post (even the incorrect one they try to dump instead of sticking on a proper scale) require electronics that output a semi-log rectification of the input signal. They will also not show output power but output voltage in a specific impedance.

All meters can be used as decoration (swinging needles that say little)
 
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JSmith

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Check this eBay ad for some power output meters... they copy in a picture of a McIntosh amp;


1632792390827.png


... and Watts is spelt Watis

1632792482508.png


:facepalm:



JSmith
 

danielbaen

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There is another major flaw in this device that I bought to switch between 2 amplifiers and why not say it, I really liked that retro look of the meters.
When you press any remote control, the brightness level of the device's lights decreases as long as you keep pressing the key and emits infrared rays .... wtf !! XD
 

pseudoid

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.... wtf !!
You know, when you floor the gas pedal, your mpg goes way down? Maybe same w/your remote: More you hold down any of the buttons; the weaker the R/C battery gets. Consider the lights dimming, as a warning to ease off on R/C button pushing.
 

pseudoid

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Clearly they don't understand dB in China. :facepalm::facepalm:
Don't be so harsh, the original confusion may not be of their own making...
History of AES17 standard is the telltale signs of the problem that loomed in the horizon; some 30+ years in the making.
 

restorer-john

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Don't be so harsh, the original confusion may not be of their own making...
History of AES17 standard is the telltale signs of the problem that loomed in the horizon; some 30+ years in the making.

Not being harsh at all. I call it for what it is, they've simply printed absolute garbage on the meter scale. It's utterly useless. Just like the re-gurgitated cassette deck meter scales, replete with 'dolby' level markers on other similar devices. :facepalm:

The Japanese never messed up meter scales. They got it right from square one. In fact, their analogue meter movements and overall quality were the world benchmark for over 50 years.
 

danielbaen

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You know, when you floor the gas pedal, your mpg goes way down? Maybe same w/your remote: More you hold down any of the buttons; the weaker the R/C battery gets. Consider the lights dimming, as a warning to ease off on R/C button pushing.
This weekend will make a video...
 

antennaguru

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There are some line level meter driver circuit boards that use a pair of small audio transformers to sample the left and right signals, without resorting to direct connection with say 10K resistors to supply the samples to the meter amplifier (driver) circuitry. I would think those would have much less, and possibly no impact on the signals being sampled due to the higher isolation provided by the transformers.

There would also be no relays, nor speaker cable switching, because VU meters should be inserted at line level.

 

Madjalapeno

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I purchased the Douk VU2 meter and sent it to @amirm to review. It turns out it wasn't very good, and was returned to the store I got it from.

I still wanted some moving meters though, so I thought I would see what I could do. I purchased a control PCB from Amazon that came with nasty meters (https://smile.amazon.com/gp/product/B07SFHV85Y/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1), some nice meters from eBay, and the important part, the input selector from @tomchr at Neurochrome (https://neurochrome.com/collections/buffers-preamps/products/input-selector).

I've now built everything up and done some testing using a MOTU M2 with ARTA.

These are basic tests done on my workbench. This is my first time testing like this and I'm not an EE.

I'll start with a loopback test, just to set a baseline.

vu_loopback.png


Next is just the input selector (no power or input to VU meter PCB).

vu_off.png


Added power to the VU PCB

vu_power.png


And then plugged in the VU meter to the PCB


vu_on.png


Finally, changed to input 2. I think the bump at 60Hz is my fault (this is all on my desk top, and not grounded in anyway).

vu_off_chan_2.png


For the investment I'm pretty happy with the results and will be building this into a nicer case.
 

Madjalapeno

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Just checked the links - the board I received is different to the one shown, but that is the link to the one I purchased. Pictures tomorrow.
 
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