Re: tda2002 - better replacements

I get nothing at all... I was hoping to get
'something', then work the circuit but didn't
happen...

--- Jess Askey <jess@askey.org> wrote:

> It looks like the LM1875 is meant for a split (+/-)
> supply while the old
> TDA is meant for a single sided supply (+/ground).
> All the inputs are DC
> isolated in the circuits but the output is not... it
> is connected to
> ground on the LM1875 which is the same place you are
> have the (-Vee)
> supply connected. The LM1875 expects a DC potential
> between Vee and the
> output which you don't have. So, Im guessing that
> you are only getting
> half the drive (the Vcc side) and it distorted and
> crappy? Or do you not
> get anything at all?
>
> Oh... looking the circuit again... the TDA drives
> the speaker through a
> cap, the LM1875 does not have the filter cap (it is
> directly loaded).
> So, that is the problem. Different output design.
> Someone else can
> probably chime in here and give a more educated
> explanation of the
> difference tho. :-)
>
> andre wrote:
> > I ordered in a couple LM1875T's which are 20w
> > amplifiers in same package as the td's. Distortion
> is
> > FAR lower and with the extra headroom, can keep
> any
> > noise down low and still have volume was objective
> on
> > AR-II's.
> > But put them in and they didn't work. Pinout looks
> to
> > be the same...anyone with any idea why they don't?
> >
> > TDA2002
> >
>
http://pdf1.alldatasheet.com/datasheet-pdf/view/54782/FAIRCHILD/TDA2002.html
> >
> > LM1875
> > http://www.national.com/pf/LM/LM1875.html
> >
> > Is the voltage too low?
> >
> >
> >
> >
>
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Received on Sat Jun 9 00:58:53 2007