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Chip Amps Amplifiers based on integrated circuits

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Old 12th April 2017, 09:06 PM   #11
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@OlegSh: Not only did I read it, I misread it too! Oh joy!

@Mark Whitney: I was building this entirely off of the supplementary document from TI: http://www.ti.com/lit/an/snaa021b/snaa021b.pdf which may or may not have been a good idea at this point... I chose the bridged design over the parallel one, purely for the decreased distortion claimed in that document. Honestly though, I am not an EE, nor do I desire to be one. This is exactly the sort of thing I would have loved to pick up in kit form.
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Old 12th April 2017, 10:04 PM   #12
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if you.. take the best of adices i can think of... that is.

stay with something simpler, a monoblock lm3886 sounds like a right choice.
do ask a lot on pcb design, it has far more to do with distortsion in case of these chipamps then bridge/paralell stuff.
learn good grounding principles, and when you are confident i might think an opamp buffered lm3886 will suit your needs.
starting out with a project that is most proably more complex than what you can overcome, is a pretty close call for a project ending without joy.
actually the tipical starter amplifier i recommend..
http://www.st.com/content/st_com/en/...rs/sta540.html
thisone, in the bridged configuration. as it requires far less components, has a fixed internal gain, and its a pretty pretty hefty chip.
give it a go.
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Old 14th April 2017, 10:09 AM   #13
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2x 34 W into 8 Ω at 22 V, 1 kHz, 10% THD

10% THD ? No thanks.
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Old 14th April 2017, 03:33 PM   #14
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at 25 watts its 1%.
and 25 watt is pretty mutch a lot of power.
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Old 14th April 2017, 09:18 PM   #15
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1% THD ? No thanks
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Old 15th April 2017, 01:25 AM   #16
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0,02% at 4 watt
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Old 15th April 2017, 04:18 AM   #17
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Quote:
Originally Posted by jaycee View Post
2x 34 W into 8 Ω at 22 V, 1 kHz, 10% THD

10% THD ? No thanks.
It's a mobile amplifier designed to run off 12 volts. It's a car radio amplifier. It's about as good as it gets without using a switching power supply or maybe a discrete circuit, which would be silly for this application.

I think it is a good chip to get your feet wet. You can hardly go wrong. A 3886 seems simple to us because if it has a problem we know right away what's wrong. A newbie might be clueless if it doesn't work. Add that to the fact that many internet circuits are incomplete and will only work under specific conditions, and you might be in store for disappointment.

I think you could build a 3886 diff amp by getting some decent mono or stereo boards, assembling them with high stability 1% (or even 0.1%) metal film resistors (like Vishay Dale CMF series), and a dedicated differential line driver like DRV134 https://www.digikey.com/product-deta...34PA-ND/275875 . I know I'm going to try it one day, and I'm going to shoot for around 100 watts RMS into 8 ohms.

Last edited by Fast Eddie D; 15th April 2017 at 04:20 AM.
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Old 15th April 2017, 06:48 PM   #18
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well actually it was designed to run not from 12 volts but up to 24 volts.
22 volt being a safe limit.
and its not a car radio amplifier.
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Old 16th April 2017, 02:58 PM   #19
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Quote:
Originally Posted by Arty View Post
and its not a car radio amplifier.
It's exactly like the chips you find inside modern car radios "50 watts RMS x4". I've taken a few apart. There's various chips in them, but it's always a 4 channel bridge amp in a "multiwatt" package. It seems to me that it was designed for this application.

Quote:
well actually it was designed to run not from 12 volts but up to 24 volts.
22 volt being a safe limit.
A bonus for the DIYer. It could also be used in a "boombox" or "mini hi-fi." But the modern trend in those is to use TDAxxx chips. I've taken a few of those apart too.

But I haven't seen this chip in any commercial products. There must be a reason for that.
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Old 16th April 2017, 05:54 PM   #20
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surely, yess it has 4 amps inside, just like car radio chips.
but car radio chips are not ment for 22 volt supply. nor does the datasheet says it was ment for any automotive application.
12V systems would be too low, 24V systems would be too high.
but works perfectly from 3x6V battery config, if you want a boombox.
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