Thanks Foster: I'll use LM386... up to now, I was conecting SP- to GND and SP+ as = an input for my amplifier... I knew I'd loose some output power from ISD b= ut... well just trying... Thanks again, Gonzalo ----- Original Message ----- From: "adastra" To: Sent: Tuesday, August 29, 2000 2:51 PM Subject: Re: [EE]: Audio amplifier and pre-amplifier Gonzalo: The ISD chip has differential outputs, intended to drive a small speake= r directly. There is a schematic in the ISD application manual which use= s an AC coupled LM-386 to convert the differential output into a single-ende= d output (referenced to ground.) It is on page 5-24 of the manual I have= , in the chapter titled "Using The Device." Of course the LM-386 still does= n't have the power you are looking for, but we sometimes use the Radio Shac= k automotive stereo power booster (their part number 12-1869)following th= e LM-386. It costs about $20, runs on 12 VDC and is rated at 40 watts out= put (20 per channel). If you drive both the left and right inputs in paral= lel, with a separate speaker on each output, you can get a pretty considerab= le volume. If you only ned 10 watts, a single channel should be plenty. If you can't find the LM-386 schematic, send me your FAX number (off-li= st) and I'll FAX it to you. Foster > -----Original Message----- > From: pic microcontroller discussion list > [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Gonzalo Jim=E9nez Yamasak= i > Sent: Tuesday, August 29, 2000 9:03 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: [EE]: Audio amplifier and pre-amplifier > > > Hello All: > > I'm trying to use a voice chip (ISD1420) but I need more output p= ower, > so I'm trying to use an output amplifier (10W max.)... Does anybody h= ave > some > schematic of one tested? (I used a TDA2003 but it didn't work well, a= ny > tips?) > > I'm also trying to improve record quality, because using the samp= le > circuit, it gets lot of noise, any suggestion here? > > Thanks in advance, > > Gonzalo > > -- > http://www.piclist.com hint: To leave the PICList > mailto:piclist-unsubscribe-request@mitvma.mit.edu > -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu