Uni-T UT81B Scope-meter question / Sound distortion

Welcome to our Forum, extension and content sharing platform of Electrical Test and Measurement Product Reviews Blog.

Registration this is Free, we accept contributors of 17 years old and above. We do not accept registration with Gmail

Active since 7 June 2012

Copyright Notice: Entire ITTSB.EU content & images they are copyright protected. - Forum search engine disabled to Guests - No need of you using Adblock software.

giavra:
Today I'm starting wondering if this low cost Item Uni-T UT81B Scope-meter Oscilloscope with around 200$ including the post cost for Greece is a crack in the market or not.I'm also wondering if this scope-meter can provide the distortion point through his sine wave presentation when you want for example to check the output sound level of your amplifier putting the pot to the level that the sound start distorts.Also as a multimeter may to accurate?

Kiriakos GR:
Dear @giavra
First of all I need to inform you that even with EMS (ELTA) your item will receive taxation 23%.
Currently I have some instruments in the customs on hold, because of the new changes.

About the Uni-T UT81B Scope-meter I do have access to one of those, it is in the hands of a close friend of my.

What I disliked on it is the low resolution of the screen, it can help as Scope-meter if you wish to measure the volts of one waveform, but by my opinion is not capable to offer the needed visual detail for fine measurements over distortion.
Especially when it comes about High End audio systems which has tremendously low distortion in their specifications.

Probably you are aware that what you need is one spectrum analyzer, and I will agree that the cost is extremely high for a hobbyist.

The advice that I have to offer to you it will very specific, you need one oscilloscope which will have an high accuracy factor, equal to the level of the distortion that you need to measure.

I am aware about the low distortion levels of preamplifier s, and that the final stages are more prone to cause an significant distortion.
But just think that with out the proper tool, you will be unable to test the quality of the preamplifier it self.
You have mention that you are making amplifiers with tubes, that the tolerances in them it is known to vary by allot.
Even so my advice is the same as to was made by modern technology.

Today I was playing with an 40 years old scope with 3% accuracy.
This is not even close to be called as acceptable performance in our times.

Phyllomedusa:
well, I do have an Higher-Range Digital Oscilloscope (Scopemeter) the Hantek DSO1202B.

First off all: If you just want to use it in a lab, you're better off with a Labscope. Well, they do need more space, but the controls are more intuitive and the performance (in the same price-range) is usually better.

The Handhelds are very nice if you need to carry them around (like I do) and can help you a lot. Unless you need the portability I would consider a Handheld scope but not as a "must-have".

I can't tell you anything about the distortion, but I can at least tell you that these Handheld normally have a very slow screen-update-rate and get pretty lazy if you use a high memory option (which some have....like 1M for 1CH/512K for 2CH).
So for finer details on your signal you could use this high memory mode (normally a Labscope starts at 1M ;)), record a period and check it on the scope (that's what I normally do if I need high res.).
Eventually that is far from a smooth workflow ;)

I would say the UT81B is nice for general checks in rough signals....like putting it in your Toolbag for testing automotive sensors..... but not a High precision Instrument.
Probably you're better off with a used Lab-Scope form ebay. The Rigols are very popular and a lot on the used-market right now.

Another thing: What Signal do you want't to compare your output to? Do you use a Function Generator or some audio-input?

giavra:
Thanks all members for their answers which much appreciate by me.Yes Kyriakos probably a spectrum analyzer is more accurate unit to test the output signal.I want to take a clear audio signal in the 1000Hz range via a test audio cd signal and take the necessary references .

Phyllomedusa:
OK. So that's fine. Yes, a Spectrum Analyzer may be helpful here. Otherwise..... most modern DSO's have a FFT mode which could help as well..... as kind of cut down Spectrum Analyzer.