Well OK, looks like the gain of the amplifier is 20 to 30 dB.Originally posted by n9xv@May 11 2006, 10:30 PM
I think this is the amp in question. I copied & pasted from crivoli's other post under projects. I think parts of the circuit in the above attachment were missing.
[post=17021]Quoted post[/post]
Originally posted by n9xv@May 11 2006, 09:30 PM
I think this is the amp in question. I copied & pasted from crivoli's other post under projects. I think parts of the circuit in the above attachment were missing.
[post=17021]Quoted post[/post]
gain as high as 1000 is way too much, use something more reasonable, like 20-200, which leads the R2 to 20k-200k.Originally posted by crivoli@May 12 2006, 11:58 AM
I am using
1K resistors for Rb,
a 1M resistor for R2,
a 1K resistor for R1,
a 10uF cap as already seen,
a .47uF cap for the coupling cap from the mic to the IC,
a LM741 IC and a 68uF cap out of the IC to the speaker....
Sorry for not posting the specs
[post=17023]Quoted post[/post]
I suspect that the LM741 is unable to drive the speaker being used. The amplifier you have constructed constitutes an audio pre-amp. Now what you need is a buffer stage capable of driving the speaker.Originally posted by crivoli@May 12 2006, 04:58 AM
I am using
1K resistors for Rb,
a 1M resistor for R2,
a 1K resistor for R1,
a 10uF cap as already seen,
a .47uF cap for the coupling cap from the mic to the IC,
a LM741 IC and a 68uF cap out of the IC to the speaker....
Sorry for not posting the specs
[post=17023]Quoted post[/post]
I switched over to a LM386 design from the datasheet and it works like a charm.Originally posted by hgmjr@May 12 2006, 05:39 AM
I suspect that the LM741 is unable to drive the speaker being used. The amplifier you have constructed constitutes an audio pre-amp. Now what you need is a buffer stage capable of driving the speaker.
You may be able to get by with a push-pull transistor amp as shown in the link below. This push pulls stage would need to be incorporated into the feed back loop of the stage you already have. This is necessary to prevent the push-pull stage from introducing excessive cross-over distortion.
Push Pull amp stage
hgmjr
[post=17025]Quoted post[/post]
That is great news. Congratulations!Originally posted by crivoli@May 12 2006, 07:09 PM
I switched over to a LM386 design from the datasheet and it works like a charm.
I appreciate everyone's advice VERY MUCH!!
Thanks again
[post=17038]Quoted post[/post]
by Jake Hertz
by Jake Hertz
by Don Wilcher
by Duane Benson