build up lm3886 as advised in datasheet... feedback resistor is 17k, all other values are as stated in datasheet... feed with +-22V and input is grounded... output voltage is -22V...
checked all connections - >looks that it´s allright... (really!! checked it minimum 10times!)
after first powering up the thing, it went into oscillation mode ;-) (sorry, I didn´t measure the output voltage at this time..)
after that I found out that the gnd rail of the v- capacitor wasn´t connected to gnd.... <- possible reason?? are thr LM´s dead?
connecting an ohmmeter to LM´s pins showed no short circuit to anything... or have I build a comparator? (but +in and -in ARE connected correctly!)
So, please make me happy an tell me what might be wrong...
Thanks!
checked all connections - >looks that it´s allright... (really!! checked it minimum 10times!)
after first powering up the thing, it went into oscillation mode ;-) (sorry, I didn´t measure the output voltage at this time..)
after that I found out that the gnd rail of the v- capacitor wasn´t connected to gnd.... <- possible reason?? are thr LM´s dead?
connecting an ohmmeter to LM´s pins showed no short circuit to anything... or have I build a comparator? (but +in and -in ARE connected correctly!)
So, please make me happy an tell me what might be wrong...
Thanks!
🙂)))))))) left it open... ooopss, ähhh is that important? I´ll try it, report in 20minutes!
I HATE THOSE SHITTY MUTING PINS!!
I HATE THOSE SHITTY MUTING PINS!!
okay 
it works now.... I must have known this, had similar problems with the TDA´s.... thought national uses a better muting function - in fact, i didn´t read the datasheet.... I shouldn´t think I know all ;-)
No, the real purpose of my thread was to proof if the forum works in the correct way - to help people 😉
Thank you Flemming!!!
it works now.... I must have known this, had similar problems with the TDA´s.... thought national uses a better muting function - in fact, i didn´t read the datasheet.... I shouldn´t think I know all ;-)No, the real purpose of my thread was to proof if the forum works in the correct way - to help people 😉
Thank you Flemming!!!
hey, I´m that type of human, who must try it first, fail, learn, and then get it right... Of course, this method isn´t professional....
Do you know my occupation? you don´t want to know it if you are a person who lost a leg ;-)
nobody´s perfect, and in fact I must make failures to learn something, not by reading books...
forgive me
Do you know my occupation? you don´t want to know it if you are a person who lost a leg ;-)
nobody´s perfect, and in fact I must make failures to learn something, not by reading books...
forgive me
I'm wondering though...if u mute the pin and it goes -V...wun it kill the speaker there?? If letsae a TV manufacturer were to use the mute pin...what should he (the manaufacturer) do to properly mute the thing??
speaker is - dead - haha, but no problem....So I´ll go ahead for an active crossover, wich one should, at least in theory, perform better for higher frequency´s and vice versa - TDA7295 or LM3886?
li_gangyi said:
no, cos when the circuit is made correctly the mute pin is never left open, it is always connected to something.... I didn't look at the data sheet so I don't know what, but yeah... lol
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