[Elecraft] Audio amps

[lhlousek]

Hi Tom,

Take a look at the TDA2003 IC. (also NTE1232)

http://www.electronic-kits-and-projects.com/kit-files/datasheets/tda2003.=
pdf

The TDA2004 is a 10W/channel  stereo version.

http://www.sweb.cz/ds01/tda2004.pdf

Jameco Electronics  (www.jameco.com) sells a number of Velleman =
(http://www.velleman.be/)  audio amp kits.  Manuals and circuit diagrams =
are available on the Velleman website.  The one that uses the TDA2003 =
device sells for $14 and is taken directly from the application note for =
the device.  Spex are 3.5W RMS (7W music power, whatever that means) =
into 4ohm at 15V.  They also sell an 18W kit for $16 (using an HA13881 =
IC) and a CEBEK 20W kit for $25.

A while back I built a switchbox which plugs into the earphone jacks of =
all my rigs so I can switch my phones between rigs quickly (also =
switches keyer between rigs).  To power a speaker from this box I added =
a TDA2003 amp in a small diecast Hammond box ( ~ 1x2x3") which also =
serves as the heatsink.  It never gets even the slightest bit warm at =
normal listening levels.  The amp connects to the switchbox via an RS =
isolation transformer and works VY FB... after adding a little filtering =
to keep RF out at QRO power levels.

Anybody complaining of low audio, particularly in mobile applications or =
other noisy environments, would do well to use one of these.

Somewhere I have seen a tiny SMT switching type audio amp IC that puts =
out a prodigious amount of power with virtually no device dissipation.  =
I'll have try and find it again.

Lou W7HV

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