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  • #61
    yogi009
    Level 43  
    katakrowa wrote:
    To make it modern, it begs to be built on op amps in class D


    What to do, it's best to buy any Chinese D-class module for PLN 8.88 and off you go.
  • #62
    katakrowa
    Level 22  
    austriackimalarz wrote:
    I would suggest converting some polyphase converter from the GPU power supply to the amplifier

    Today, in fact, the effect would probably be similar, but as you can see, the heat emitted by the WO is a big problem, as evidenced by this whole topic.
    I bet that within 10 years there will be such class D WOs that will be indistinguishable from analog ones in the audio band.
  • #63
    austriackimalarz
    Level 26  
    katakrowa wrote:
    I bet that within 10 years there will be such WOs in class D, which in the audio band will be indistinguishable from analog ones.

    They are like that today. Interestingly, these are still "single-phase" models, and they do not switch at megahertz, but closer to the standard 300-500kHz.
  • #64
    katakrowa
    Level 22  
    austriackimalarz wrote:
    They are like that today. Interestingly, these are still "single-phase" models, and they do not switch at megahertz, but closer to the standard 300-500kHz.

    Can you provide some model?
  • #65
    marweg1967
    Level 12  
    yogi009 wrote:
    I wouldn't get into quad dice for several reasons. Cooling, crosstalk, the ability to replace the system with another

    In theory you're right, but:
    1. The sum of the power dissipated will be rather similar in each case, so the surface area of the heatsink will also be. In the absence of a heatsink, double, and even better single, will do better.
    2. Crosstalk... But in each opamp will be the same...
    3. I was thinking about the SMT version, so no one will play with resoldering ICs. At most, it would be possible to use the design of the board.
    In general, I treat the project as a curiosity, with the option of making two or more versions, e.g. "high end" on NE5532 and better components (no exaggerations in the style of kondy for several hundred zlotys) and "popular" on SMT and just TL074 in such a version. It will be interesting to compare such constructions both in terms of measurement and hearing. :)
    Why such opamps? Let's say I'll trust Douglas Self, who quite clearly justifies the lack of sense in using "better" chips than the NE5532 in general and the TL07x in applications requiring input FETs.
  • #66
    Jaro
    Level 27  
    austriackimalarz wrote:
    We settled on the TL071HIDBVR, which is the well-known TL071 in the SOT-23 housing


    I'm not sure it's a good choice. The documentation contains only a functional diagram, but if the modern versions do not differ much from the earlier TL06x TL07x and TL08x, they have a primitive and inescapable "short-circuit protection" in the form of a final stage with 100-ohm emitter resistors and another 200-300 Ohm resistor connected in series with the WO output to load. It does not matter much in typical applications of these WO, but here we have an unusual application, because even for the parallel connection of several dozen or even several hundred such circuits with a load in the form of a loudspeaker, this will have an impact limiting the output power and the Damping Factor.
  • #67
    marweg1967
    Level 12  
    Jaro wrote:
    austriackimalarz wrote:
    We settled on the TL071HIDBVR, which is the well-known TL071 in the SOT-23 housing


    I'm not sure it's a good choice. The documentation contains only a functional diagram, but if the modern versions do not differ much from the earlier TL06x TL07x and TL08x, they have a primitive and inescapable "short-circuit protection" in the form of a final stage with 100-ohm emitter resistors and another 200-300 Ohm resistor connected in series with the WO output to load. It does not matter much in typical applications of these WO, but here we have an unusual application, because even for the parallel connection of several dozen or even several hundred such circuits with a load in the form of a loudspeaker, this will have an impact limiting the output power and the Damping Factor.


    Thanks for the warning. In fact, in this situation you would have to go into thousands of WO. But a fellow Austrian painter has just such an intention. I'm even more curious about the end result :)
  • #68
    tytka
    Level 21  
    marweg1967 wrote:
    Will your colleague share details about this security? Input diodes? Because this Behringer makes a really bad noise and I'm getting ready to etch the board to use the workaround described by my friend (I already have the parts). So I would add this protection right away.


    Please check the topic again link , I posted new information.
  • #69
    marweg1967
    Level 12  
    tytka wrote:
    marweg1967 wrote:
    Will your colleague share details about this security? Input diodes? Because this Behringer really hums badly and I'm getting ready to etch the board to use the workaround described by a colleague (I already have parts). So I would add this protection right away.


    Please check the topic again link , I posted new information.


    I looked :) I imagined something more or less like that, except that I was thinking about an anti-parallel connection of sets of ordinary diodes (3-4 in series), or JFETs working as diodes. I wonder if these Zener tubes don't make any noticeable noise, although probably not since you left it like that?

    I would like to thank my colleague for keeping his word and best regards :)