Beginners - A simple bass amplifier.

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 A simple low-frequency amplifier.
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 (r)&(c) VTS'99

 Then somehow in the 7th Format I came across
to the amplifier on KA2209. It was presented there
mono version (and KA2209 has two channels) with
bridge connection, which allows for pi-
Tania 5v get output power up to 1.5
W into 8 ohm load. At a load of 4 ohms you can
but get up to 3 W (which is already quite enough)
exactly), but the microcircuit will heat up a lot -
xia, therefore use such an inclusion
undesirable. Although you can try
pour the radiator. Ooops, I completely forgot
say: the described chip WORKS WITHOUT
RADIATOR  and is located in SMALL-SIZED
CASE DIP-8pin !!! And it costs the SAME
as much as K17CHUN14 (about 0.5$) !!! WhenVolume UN14 heats up even in idle mode, and
has only one channel, i.e. for 3W it
needs to be powered from 12v (which may not be
be...), and you need a lot of details around it
catchy ;)

 And here is the diagram.

 o──┐ + 1Omk 0.01-0.1μ
 input │ ┌──╢──┬──╢──┤
 ║ │ ┬ │
 10-47k ║<───┼─┐ │ │
 volume ║ 8.─.─.─.5
 │ │ │ KA2209
 │ │o │
 ┴─ 1.─.─.─.4
 │ │ │ │
 │+5v│ ┴
 │ │
 └─П─┘
 /_ speaker

 However, it is much more interesting to  do it on
this tiny onemikruhe stereo amplifier.
Because  I don’t have any documents, but reference books are used
screw it up, the method of scientific research was used
ka. And the following happened:


 o left o right
 │ │
 │ 10-47k 10-47k │
 ║ ║
 ║<─────────┐ ┌──────────>║
 ║ ┬ │ │ ┬ ║
 │ 0.01- ╪ │ │ ╪ 0.01- │
 │ -0.1μ │ │ │ │ -0.1μ │
 │ 8.─.─.─.5 │
 ─┴─ │ │ KA2209 ─┴─
 │o │
 1.─.─.─.4
 │ │ │ │
 │+5v│ ┴
 +│ │+
 47Omk ═╪═ ═╪═ 47Omk
 │ │
 │║ ║/│
 left │/║ ║│ right
 │ │
 ─┴─ ─┴─

   The volume control in this case should
wives to be doubled (although whoever likes it -
Xia).

 This circuit will give four times less power
number per channel, but this can also be
quite enough, for example for headphones
(by the way, the mikruha also works at 3v!) or
small-sized speakers.
   So, at 5v at 4(8) ohm load
children up to 0.7(0.35) W.

 By the way, you should remember that from each
chip channelshould not be removed more than
1 W (it will continue to heat up).

   And it won’t hurt in the immediate vicinity
Sorry to put capacitor 100 uF on pi-
tania.

   And if the power is taken from the computer,
it is advisable to add a filter (so that the pulse
No strong interference got through and the sound was clearer):

 100-4OOmkH 1OOmk
 +5v <───///────┬─────┬────> +5v
 from the computer │ │ to the amplifier
 0.1 micron ═╪═ ═╪═
 │ │
 ─┴─ ─┴─

   The inductor can be wound on ferrite
ring with a diameter of 10-2Omm and permeability
1000-3000.  It is necessary to wind at least
30-40 turns.

 Well, that's it...