TDA1543 resistor i/v

[till]

experiment

sounds realy bad:

[till]

sound better :

[Bricolo]

you have to put something between vref and gnd

http://jwg.student.utwente.nl/fedde/images/nonoz3.gif

[jean-paul]

Hereby a pdf of what's been discussed to death. It was explained excellent by Rbroer:

[till]

"you have to put something between vref and gnd"

my datasheet say " R bias - optional " what should mean i don´t need it it the shown config.

[Bricolo]

I think it's optionnal with an opamp IV, not with a passive IV

[carlosfm]

till, with passive I/V, it's very critical the value you use between Ref and ground.
You have to use a resistor there.
I always use a 2.2k trimmer and it's so critical that you can tune it by ear.
Sound goes away, hiss, comes back distorted and finally clear (in both directions this happens).
There's a sweet spot thats not wide.
In the end you can measure the trimmer and put a resistor of that value there.
Unfortunately, the position where it sounds best is not the one with lower DC.

[Bricolo]

but there's no advantage in having a low DC, since you have a cap at the output

[carlosfm]

Of course.
Better with no cap, but not here.

[till]

I did the trimmer at Vref some time ago, and i ended up with very low resistance there.

The reason for this attempt was i wanted without the resistor, and i´m sure it will work without. (datasheet)

Following the information in posting above and the datasheet i would need to set the voltage with the divider to about 2,3V, and use 650R/760R resistors.