hi
i start to bouild the F5 amplifier by nelson. the input impedance of the amp is 100K and the gain is 15db, so i feel that is need preamp.
my audio surce is sound card so in the output it have ~400mv.
i want to bay this preamp(the LME49720 is very quality specsification)
http://www.ebay.com/sch/i.html?_trksid=p2047675.m570.l1313.TR0.TRC0.XTone+Control+3-Way+Audio+preamplifier+KIT%2C+Lowest+THD%2BN+Bass%2F+Mid%2F+Treble&_nkw=Tone+Control+3-Way+Audio+preamplifier+KIT%2C+Lowest+THD%2BN+Bass%2F+Mid%2F+Treble&_sacat=0&_from=R40
do you think its 20db gain is enough ? maybe i need less gain?
thanks
i start to bouild the F5 amplifier by nelson. the input impedance of the amp is 100K and the gain is 15db, so i feel that is need preamp.
my audio surce is sound card so in the output it have ~400mv.
i want to bay this preamp(the LME49720 is very quality specsification)
http://www.ebay.com/sch/i.html?_trksid=p2047675.m570.l1313.TR0.TRC0.XTone+Control+3-Way+Audio+preamplifier+KIT%2C+Lowest+THD%2BN+Bass%2F+Mid%2F+Treble&_nkw=Tone+Control+3-Way+Audio+preamplifier+KIT%2C+Lowest+THD%2BN+Bass%2F+Mid%2F+Treble&_sacat=0&_from=R40
do you think its 20db gain is enough ? maybe i need less gain?
thanks
thanks, its good article.
now im sure that if i want 25w on the F5 output, i have to amplified the computer signal.
but how much? i thins 20 db its ok, im worng? 0.3v *30 (F5)=9=>10W
so what i need is 0.8v in the entrance of the F5 to get 25w on the speaker !?
if so, the preamp in need to amplified by ~2 ! ?
i just want to be sure before i buy this preamp
thanks
now im sure that if i want 25w on the F5 output, i have to amplified the computer signal.
but how much? i thins 20 db its ok, im worng? 0.3v *30 (F5)=9=>10W
so what i need is 0.8v in the entrance of the F5 to get 25w on the speaker !?
if so, the preamp in need to amplified by ~2 ! ?
i just want to be sure before i buy this preamp
thanks
With the F5's voltage gain of 15.3dB=20*log(x) and a maximum output voltage of +/-20V (from manual), the amplification factor x=10^(15.3/20)=5.82 and therefore the input voltage required to drive it to full output should be 20V/5.82=3.42V. Compare this to what your source can deliver, and decide on how much gain you'll need in the preamp stage.
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