mute/standby? on chip amp

Discussion in 'General Electronics Chat' started by chunkmartinez, Mar 12, 2013.

  1. chunkmartinez

    Thread Starter Senior Member

    Jan 6, 2007
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    Can anyone tell me what the mute and standby do? How to use them? Are they basically on switches?

    I'm using the TDA7293. Does anyone know how much real-world RMS power I can get out of this? I have a 300VA 43-0-43 transformer
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    From the TDA7293 Datasheet

    Maximum Power: 100W @ 10%THD into 8Ω with ±40V Rails (Ten Percent Distortion, not 0.10%) NOT SUGGESTED

    Page 7 shows timing for Mute and Standby signals at Power On/Off to eliminate Speaker "pop" when power is applied/removed. Also on Page 7 of the datasheet is a single button circuit with 2 capacitors for a "pop noise free" mute button (mutes audio, puts IC in standby, on release, takes out of standby, releases mute).

    Mute disables audio output.

    Standby causes IC to go into low power mode: 1mA Quiescent current in standby, vs 100mA quiescent current in Active/non-standby mode.

    Usable Power (Distortion < 0.1%) - 60W(4Ω) / 50W(8Ω) (from Figures 9 and 10 on top left of Page 12)

    Datasheet has some nice pre-made board layouts for using the IC, which is nice.

    Package will Dissipate 20W of HEAT with an 8 Ohm load and 40V supply. Use appropriate heatsink! Dissipated heat jumps to 40W into a 4Ω Load.

    Frequency response looks good.

    2 of these, one for each channel, would make a nice 100W Stereo amplifier (50W/Channel), but will be rather heavy due to transformer, and very large heat sinks. Remember, it will only sound as good as your power supply, so don't skimp on filtering (separate board).

    I'd also suggest another board with relays to mute if heat sink temp gets too hot.
     
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  3. chunkmartinez

    Thread Starter Senior Member

    Jan 6, 2007
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    Great advice, thanks..Is that power figure RMS power? Also, can you understand the clip detection lead? Is it a built in clip detector I can wire to an LED circuit?
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Yes. "Peak Power" would be roughly 800W going by how some chinese mark up their amps, using I²R. That's using the 10A max current and 8 ohms, so 100*8, resulting in 800W "Peak Power", but that's a useless number.

    It will sound MUCH better at a given volume than a $50 "200W Stereo Amp" from a big box store, provided you use good power supply, speakers, and follow the design specs in the data sheet.

    --ETA to your edit:

    Yes, the clip detector is a FET current sink if you look at the design schematics.
     
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  5. chunkmartinez

    Thread Starter Senior Member

    Jan 6, 2007
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    Awesome..I'm really wanting to get into the circuit. I am protoing it up rightnow with my breadboard. Do you have an idea how many of these IC's I can run with a single 300VA transformer at a 60W output? I figure at 8 ohms my power dissipation will be 80W per IC. And a 300VA transformer will be good for 300Watts, correct? So roughly 4 IC's at 60W output a peice?

    Also, did you see anything on bridging two together? I have seen theseon ebay where the seller says two are combined for a sub out.
     
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    See Page 8 of the datasheet for multiple and bridging.

    Actually, I'd suggest reading the entire datasheet before building up an app. Max draw per IC is 8.5A, 10A in overload.
     
  7. chunkmartinez

    Thread Starter Senior Member

    Jan 6, 2007
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    Any notes on a proper power supply? The only supply I know to do is to use a bridge config with standard diodes that handle the voltage/current I need, with the center tap of the transformer as a GND, and use the largest capacitors I can that are rated for my voltage rails. I have 2 2200uF caps yxf rubycons. I also have large shotky diodes, should I use them? Also, what sort of values can I use for HF noise? small value plyester capacitor? What else am I missing?
     
  8. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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  9. chunkmartinez

    Thread Starter Senior Member

    Jan 6, 2007
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