logo elektroda
logo elektroda
X
logo elektroda
Advanced Search
logo elektroda

Using LM358 IC for Dual VU-Dial Indicator System in Plastic Housing: Tips & Tricks

elektronik.b 18600 98
ADVERTISEMENT
Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
Reply Cool? Ranking DIY | New topic
Notify about new articles
  • #31 19378382
    bratHanki
    Level 38  
    Give it up now. The author wanted to make a "dangle" and he did. He is satisfied with the action, and that's what counts. Everything could be done better, but from what he wrote, he has no intention of doing a recording studio or broadcasting music over the air so fine scaling is not needed. This is my opinion and I agree with it completely.
  • ADVERTISEMENT
  • #32 19381258
    elektronik.b
    Level 3  
    bratHanki wrote:
    Give it up now. The author wanted to make a "dangle" and he did. He is satisfied with the action, and that's what counts. Everything could be done better, but from what he wrote, he has no intention of doing a recording studio or broadcasting music over the air so fine scaling is not needed. This is my opinion and I agree with it completely.


    And that's it :)
  • #33 19381549
    zulusj23
    Level 25  
    The LM358 is a dual operational amplifier. Why are there two tiles? Are these layouts based on the diagram from the first post? Unless I missed something and did not read what the other half of each bone is doing, I'm sorry.
  • #34 19381641
    398216 Usunięty
    Level 43  
    zulusj23 wrote:
    I missed something
    Well, rather ...
    Gizmoń wrote:
    You had to make full use of one LM358 chip instead of two, only half of each. How can amplifiers be wasted like this? :D Everything would then fit nicely on one PCB.
  • #35 19383357
    żarówka rtęciowa
    Level 38  
    Hello

    I think that popular and cheap J-Fet amplifiers, for example from the TL08x series, could be used in this design.
  • ADVERTISEMENT
  • #36 19409354
    Sanjose
    Level 32  
    I am interested in the frequency response of the amplifier of these indicators. Make the popular audio sweep test 0 - 20kHz.
    The LM358 is rather poorly suited as an amplifier for drive indicators.
  • #37 19595012
    elektronik.b
    Level 3  
    Sanjose wrote:
    I am interested in the frequency response of the amplifier of these indicators. Make the popular audio sweep test 0 - 20kHz.
    The LM358 is rather poorly suited as an amplifier for drive indicators.


    I did this audio sweep test 0 - 20kHz, but what is the result of it? the hands swing up to a certain point at some frequency.
  • ADVERTISEMENT
  • #38 19595070
    Sanjose
    Level 32  
    elektronik.b wrote:
    I did this audio sweep test 0 - 20kHz, but what is the result of it?


    It is supposed to indicate whether the indications of the indicator are the same for the frequencies of 20Hz and 20kHz and are the same in this frequency range.
  • #39 19595085
    elektronik.b
    Level 3  
    They are the same. I checked.
  • #40 19595103
    398216 Usunięty
    Level 43  
    First you write
    elektronik.b wrote:
    the hands swing up to a certain point at some frequency.

    Which suggests that the indications differ, and then you answer your colleague's question
    elektronik.b wrote:
    They are the same.

    After all how?
  • #41 19595111
    elektronik.b
    Level 3  
    As I wrote before, at 20Hz and 20kHz the indications are the same. Only at frequencies below 20Hz do they swing out to the maximum.
  • #42 19595156
    398216 Usunięty
    Level 43  
    elektronik.b wrote:
    Only at frequencies below 20Hz do they swing out to the maximum.
    This is at least strange ... not to say suspicious.
    And if this is the case, your indicators show what they want and do not serve anything else than lighting (instead of a night light).
  • #43 19595345
    Sanjose
    Level 32  
    It should work like this:




    Sometimes at 20kHz some circuits can slightly raise the indications up, but the difference is usually 0.5 VU not more.
  • #44 19595648
    elektronik.b
    Level 3  
    Quote:
    This is at least strange ... not to say suspicious.
    And if this is the case, your indicators show what they want and do not serve anything else than lighting (instead of a night light).


    They really indicate that, and you are actually right in showing what they want.
    So what should he do to make them point like on the test shown by my colleague Sanjose?
  • #45 19595730
    398216 Usunięty
    Level 43  
    elektronik.b wrote:
    what should I do to make them indicate the same as on the test shown by my colleague Sanjose?
    Use a PROVEN control system. There are plenty of them on the web.
  • #46 19595871
    bratHanki
    Level 38  
    Electronics, b do not worry about the comments because you do not create a world-class recording studio, but a gadget that is supposed to swing to the beat of the music and only serve this purpose. For decades, simple control systems were used in the tape recorders manufactured by us, and not only, and somehow no one was picking on, because they were sufficient for amateur needs. For example, the control meter from the M2405 conveyor belt.

    Using LM358 IC for Dual VU-Dial Indicator System in Plastic Housing: Tips & Tricks

    If you showed something like this, you would probably be eaten in the second, at most in the fourth post.
  • #47 19596156
    elektronik.b
    Level 3  
    Quote:
    There are plenty of them on the web.


    I was looking and the only simple system I found was the one from the first post, the rest did not work for me.
    And if you are so smart, find it yourself.

    Added after 45 [seconds]:

    bratHanki wrote:
    Electronics, b do not worry about the comments because you do not create a world-class recording studio, but a gadget that is supposed to swing to the beat of the music and only serve this purpose. For decades, simple control systems were used in the tape recorders manufactured by us, and not only, and somehow no one was picking on, because they were sufficient for amateur needs. For example, the control meter from the M2405 conveyor belt.

    Using LM358 IC for Dual VU-Dial Indicator System in Plastic Housing: Tips & Tricks

    If you showed something like this, you would probably be eaten in the second, at most in the fourth post.


    HOLY right.
  • #49 19596387
    yogi009
    Level 43  
    All this can be summarized briefly: the first cats behind the fences. You will do the next DIY on one PCB, you will add the possibility of calibration there, and if such a PCB fits dimensionally with the "back" of the indicator, it will be too much luck. Krakow wasn't built in a day. It is important that you are doing something.
  • #50 19596432
    398216 Usunięty
    Level 43  
    elektronik.b wrote:
    And if you are so smart, find it yourself.
    I? I do not have to. I don't make useless devices that do nothing but wag directions - quite pointless after all.
    yogi009 wrote:
    the first cats behind the fences. You will do the next DIY on one PCB, you will add the possibility of calibration there, and if such a PCB fits dimensionally with the "back" of the indicator, it will be too much luck.
    Well, unfortunately, it is not so. A colleague has already placed a few constructions in DiY and somehow he did not draw any conclusions from the suggested changes. Yes, this "Krakow" is a bit neglected ...
    elektronik.b wrote:
    I was looking and the only simple system I found was the one from the first post, the rest did not work for me.
    Interesting, isn't it? And what other systems (those that did not want to work) did you make? Maybe it would be enough to think why they don't work, ask someone ... wiser ...?
    bratHanki wrote:
    For decades, simple control systems have been used in tape recorders (conveyor belts) produced by us and not only, and somehow no one was picking on,
    Because they worked as they should. Small difference...
    I wrote earlier:
    398216 Usunięty wrote:
    CodeBoy wrote:
    I don't like something about the scaling of the excursions, they work too much on the positive half of the scale, they should start more around -20 and move around 0dB
    In general, the time from the occurrence of a signal of a given level to its indication, as well as the time in which the indication falls after the signal ceases, is quite strictly defined for this type of indicators. Here it is just something that fans the clues to the beat of the music. There is no practical benefit from this.
  • ADVERTISEMENT
  • #51 19596443
    yogi009
    Level 43  
    398216 Usunięty wrote:
    Well, unfortunately, it is not so. A colleague has already placed a few constructions in DiY and somehow he did not draw any conclusions from the suggested changes. Yes, this "Krakow" is a bit neglected ...
    elektronik.b wrote:


    I don't follow the author's construction history, I don't have that much time :-) On the one hand, I believe that everyone should be given a chance, and on the other hand, the constructor should learn and improve his projects.
  • #52 19596451
    398216 Usunięty
    Level 43  
    You don't have to follow - just click on the links to his topics under each of his posts. :)
  • #54 19596507
    398216 Usunięty
    Level 43  
    elektronik.b wrote:
    What do you think I'm stupid ????
    I didn't say anything like that. Once someone much smarter than us said, "I know I know nothing" and this is the best example of how to approach your knowledge. I have at least several dozen years of practice, several years of study (anyway, electronics have it that if you do not keep training, you stay behind), And what can you be proud of? Of course, apart from an exaggerated ego?
    elektronik.b wrote:
    This is good, I would also need a mosaic pattern of paths.
    And did you read the entire article from the link or just the beginning? An example pattern of paths is - and even if it wasn't, what's the problem to draw (e.g. in the free EAGLE) of your version? I've seen bigger beginners than you in the DiY section and they've had no problem with that.
  • #55 19596649
    yogi009
    Level 43  
    elektronik.b wrote:
    This is good, I would also need a mosaic pattern of paths.


    And here, I will constructively suggest two programs (to choose from): Eagle or KiCad. The latter is completely free and unlimited. You will draw a diagram, arrange the elements manually, lead paths and, as a result, you will become a better person :-) And certainly a little better electronics. Independent investigation of the truth and learning about methods frees a person, makes him independent from the help of others. It's worth learning.
  • #56 19596751
    zgierzman
    Level 31  
    elektronik.b wrote:
    Quote:
    Maybe it would be enough to think why they don't work, ask someone ... wiser ...?


    What do you think I'm stupid ????



    "Stupid" is too thick a word, but if "they don't work", it means that you are either doing something wrong but don't know what, or you are not able to diagnose that the pattern is wrong and correct it. In both cases, they will find themselves smarter than you ... Nobody is omniscient, Alpha and Omega, these are just religious stories. Normal people have to be able to admit their ignorance, but that doesn't mean they are "stupid". Only a truly stupid will think so ...

    But the fact that you haven't been trying to improve your constructions for a while, but you are wading into the same dead end with maniacal stubbornness.
  • #57 19646480
    Olkus
    Level 32  
    elektronik.b wrote:
    bratHanki wrote:
    You can try something like this. https://ep.com.pl/projekty/miniprojekty/11975...rownik-wkietanika-wychylowego-do-wzmociągacza


    This is good, I would also need a mosaic pattern of paths.


    The plate below in the attachments :)
    Give at least a plus for your time drawing this :P

    @elektronik.b print first on a regular sheet to check if the dimensions suit you and if the elements you have fit.

    Regards,
    AND.
    Attachments:
  • #59 19649328
    Sanjose
    Level 32  
    Why can't you use symmetrical tension?
  • #60 19649358
    398216 Usunięty
    Level 43  
    ]
    elektronik.b wrote:
    Does anyone know how to convert this system so that it can be powered with a single 12V voltage?
    elektronik.b wrote:
    What do you think I'm stupid ????
    The slogan for today: "Artificial mass"
    Besides, you also have Google ... and even a forum:
    https://www.elektroda.pl/rtvforum/topic3559115.html
Reply Cool? Ranking DIY | New topic
Notify about new articles
Report a violation of the law

Topic summary

The discussion centers on a DIY dual VU-dial indicator system using LM358 operational amplifiers housed in plastic enclosures. The original design employs two separate PCBs with half of each LM358 chip used per channel, though it is suggested to consolidate both channels on a single PCB utilizing the full dual op-amp to reduce size and wiring complexity. The indicators are illuminated by front-facing LEDs, which many recommend replacing or covering to mimic original backlit designs for better visual comfort and authenticity. Calibration and scaling issues are noted, with the indicators often saturating near maximum deflection and lacking proper logarithmic response. Several contributors propose adding diode and resistor networks to improve linearity and dynamic response, referencing existing proven control modules and circuits, including those based on TL084 J-FET op-amps for better performance. Power supply considerations include symmetrical versus single 12V supply configurations, with suggestions for using Delon doubler rectifier circuits and appropriate diode (1N4007) and capacitor (≥100µF) values for filtering. PCB layout improvements focus on minimizing track lengths, using jumpers, and considering THT versus SMD components based on soldering skill and size constraints. The frequency response of the LM358-based amplifier was tested from 20Hz to 20kHz, showing consistent indicator deflection except for anomalies below 20Hz, indicating limited suitability of LM358 for precise VU metering. The community encourages iterative design refinement, calibration against known signal levels (e.g., 0 dB at 0.775V), and learning through schematic and PCB design tools like KiCad or Eagle. The Nissei TN105 BW indicator is mentioned as a specific meter model requiring scale adjustments. Overall, the project is recognized as a functional but basic audio level visualization device rather than a professional metering instrument.
Summary generated by the language model.
ADVERTISEMENT