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Technical Pro VU Meter Review

Rate this product:

  • 1. Poor (headless panther)

    Votes: 77 88.5%
  • 2. Not terrible (postman panther)

    Votes: 7 8.0%
  • 3. Fine (happy panther)

    Votes: 1 1.1%
  • 4. Great (golfing panther)

    Votes: 2 2.3%

  • Total voters
    87

amirm

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This is a review and detailed measurements of the Technical Pro dB30 LED VU/bar graph meter, outlet strip and USB charger. It is on kind loan from a member and sells for $59.
Technical Pro dB30 VU Meter Review Professional LED.jpg


I really like the 1U rack form factor and solid metal box. The functionality is excellent with USB charging port in the front and outlet strip in the back:

Technical Pro dB30 VU Meter Review Back Panel Professional LED.jpg


So this is not just some pretty lights that take up space. You would replace your power strip with it and get a bonus level meter.

Technica Pro DB30 Measurements
The problem with previous budget VU meters we have tested is that they severely load down the input causing it to distort. Let's see if we have the same problem here:
Technical Pro dB30 VU Meter Measurements Professional LED.png


There are two gain potentiometers (on the right) that are set to the detent center position as shipped. Using that, the analyzer starts to distort above 1.2 volt (blue line). Specification is 1 volt input so you could say that is fine but just about every DAC we have outputs 2 volts in unbalanced mode so we care what happens there.

Fortunately, if you reduce the gain with those pots so that 1 volt is the max on the LED, there is no impact at all on the device feeding it. But then you have a problem. All the LEDs shut off then at -16 dB. This is not much range and totally contrary to the markings indicating 5 dB to 140 dB. They are saying 135 dB range but we are only getting 16.

That is not the only problem. The major issue is instability. If I just set the analyzer to a level of say -5 dB, the LEDs jump forward and back by as much as 5 lights! Was hard to capture the full range with my camera but this should give you an idea:
Technical Pro dB30 VU Meter -2 dB Measurements Professional LED.jpg


Wait a few seconds and you get this:

Technical Pro dB30 VU Meter -2 dB Run 2 Measurements Professional LED.jpg


The thing was just dancing back and forth with input level not changing at all. It would actually light up two red LED at times.

I don't know what you do with a VU meter which dances around on its own. And with such limited dynamic range.

Conclusions
A marketing genius came up with this functionality and another genius produced it so sells for just $59. If it only worked and did something useful, it would be a killer. But sadly, it doesn't work. I suspect it would only cost a bit of money to put a proper buffer in there and get rid of noise/oscillation and make this work. Hopefully they read this and fix the issues.

I can't recommend the Technical Pro dB30. I don't need an instrument here but do need stability of the display and wide dynamic range.

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solderdude

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Maybe a short YT video to show the meter's response.

What is the dB scale about (100dB opposite what ?)
 
Last edited:

JSmith

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I don't know what you do with a VU meter which dances around on its own.
Basically not fit for purpose... grounds for a return/refund in many countries. Unsure why they bothered making this if it can't perform it's most basic function.

On the lighter side of things, did you listen to it... somehow? :cool:


JSmith
 

PenguinMusic

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Christmas-lights for audiophiles. There are no bad products, only bad marketing.*
* I jest
Hi,

Yes, of course, blame it on the audiophile.
Again...

I thought an audiophile (which seems to be the latest insult on this site/forum) is the one spending a lot of money on snake oil that is marketed to improve sound but does not.

Where would that fit a product that makes light, does not pretend to improve sound and costs less than 60 dollars.

Blame it on the christmas lights, not the audiophile. For once...
 

Madjalapeno

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Now if only they had made the case from marble it would be an audiophile dream - inaccurate, impractical, heavy, and makes things sound worse.

Still might get one though, just for a 1U power distribution, as long as it doesn't to a Carver on me.
 

beagleman

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Radio Shack actually made a similar item back in the 80s that was somewhat useful and functional. Minus the outlet strip thing on the back.

I remember them being hooked up in the store, and it actually SHOWING a relatively accurate decibel rating.
Not perfection, but why can it not be done today, with even radio shack accuracy....sad.
 

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AndreaT

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Another botched attempt to add functionality. It adds distortion and inaccuracy, increasing the unknowns of what you mistakenly think have become known levels. Hanging by the feet decapitated panther.
 

Ralph_Cramden

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There’s a simple solution to these meters bogging down the line. I simply use a Pi Zero running Squeezelite to drive the meter, then group it with another that drives my RME. No distortion. No problem.

AVvXsEjnbAPBhoNh2yArQl8g_29quq4Q1UX2Kqt4UinF0bh3lNHw1tkZ-VrABhXJirEeH8QdhRNn94VMXJ0oOrDbeK4OIUQYO-1BWl3q8DscjQgg2hzYAWRVynAFssZ0ERxpeqz0nglQMj_supW_hW2jAG8XbsgT8NO4fvLNXDKECuO0ri-Vjb7Ykk4mWCcIVg=s1206
 

sergeauckland

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Apart from providing a bit of a light show and/or some visual interest, what's the point of a VU meter? It doesn't show levels or actual loudness so why bother? I can understand using a true-peak meter, I can even understand using a Type 1 PPM (as I do) or even a Type 2 PPM with BBC 1-7 scale if that's what one's used to, but VU? Virtually Useless.

S.
 

tvrgeek

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This review points out a common problem with about any monitoring circuit. It may seem wise to add a DC sense or over current sense to an amplifier, but I have yet to find circuits that create less distortion than a fuse, which in not totally beguine. High enough impedance seems to lead to errors that make the circuits not perform as needed.

Back in the days of the Simpson 260, we had to be very aware of our measurement techniques. I wonder Fluke has made us lazy?

Yea, meters on a playback system are useless. Maybe a circuit that does not cause distortion, with long hold time to identify 5% from clipping would be sort of useful, but all it would really say is you did not think before you bought the amp and bought the wrong one. Setting aside the ego-eye candy mine is bigger eye candy stuff. Some put value on that which is their choice.
 

Lambda

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I can think of a view more interesting tests for this device

  • Linearity over frequency.
Dose a 20hz or 20khz signal show the same amplitude as a 1khz signal.

  • Crest factor or RMS.
How dose crest of an signal change the display. is it True RMS or Average or peak?


But i realize it is a decorative toy and not a measurement device.
 

Azathoth

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Hmm, I've been looking at a Furman PL-8C recently, heard it's a good power strip that also doubles as an AVR and a surge protector. I thought this did the same thing but it seems to only have USB charging and VU meter? And it doesn't even do it that well. Sucks.
 

Ismapics

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There’s a simple solution to these meters bogging down the line. I simply use a Pi Zero running Squeezelite to drive the meter, then group it with another that drives my RME. No distortion. No problem.

AVvXsEjnbAPBhoNh2yArQl8g_29quq4Q1UX2Kqt4UinF0bh3lNHw1tkZ-VrABhXJirEeH8QdhRNn94VMXJ0oOrDbeK4OIUQYO-1BWl3q8DscjQgg2hzYAWRVynAFssZ0ERxpeqz0nglQMj_supW_hW2jAG8XbsgT8NO4fvLNXDKECuO0ri-Vjb7Ykk4mWCcIVg=s1206
I would love to lear how to do this. Can you point to a knowledge base of content that explains how to. Thanks
 

xema

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Before I clicked in: It's just a VU meter, do we really need to do this?
After I clicked in: Oh....
 

sergeauckland

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There’s a simple solution to these meters bogging down the line. I simply use a Pi Zero running Squeezelite to drive the meter, then group it with another that drives my RME. No distortion. No problem.

AVvXsEjnbAPBhoNh2yArQl8g_29quq4Q1UX2Kqt4UinF0bh3lNHw1tkZ-VrABhXJirEeH8QdhRNn94VMXJ0oOrDbeK4OIUQYO-1BWl3q8DscjQgg2hzYAWRVynAFssZ0ERxpeqz0nglQMj_supW_hW2jAG8XbsgT8NO4fvLNXDKECuO0ri-Vjb7Ykk4mWCcIVg=s1206
By the way, to pass the time on a miserable day, I checked the virtual VU meter on my Squeezebox Touch, which presumably is the same as on Squeezelite, and to my surprise, the dynamics were to specification. It indicates 0VU with a -2dBFS signal, and correctly indicates 99% with a 300mS toneburst.

S.
 
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