little or no amplification on tda1554

[kasemodz]

Alright, I have a tda1554 audio chip. I used this schematic for my amp. Right now I don't have any capacitors running on the input but however I should hear some amplification. Here is the schematic I used. Has anyone else had this problem?

 

[peranders]

Right now I don't have any capacitors running on the input

This may be your problem. First: Have you checked the datasheet where you can read how a basic application looks like? A good advice is not to start to change a design without knowing how it works. Since you have a single supply it's most likely that you must have AC coupled inputs and outputs.

 

[MikeB]

Okay, you can't run an amp with single voltage supply without inputcaps, this can't work as the amp will permanently clip at negative, the input is biased to ~Vcc/2 internally. Which schematic did you use, the left or the right ?

Mike

 

[sagarverma]

using no caps at input is bad idea,more so for a single supply amp.
1554q was my first amp,i tested different values of i/p caps and at last settled for 10uf.
i used 10pf i/p cap also and the result::no o/p for the given i/p.i wonder how u r hearing anything at all.

 

[kasemodz]

i used the right one with the two channels. Replying to the second post, the capacitors just remove the "noise" from the sound input. I should still receive some amplification. Replying to third post, what do you mean by the power supply. I'm a little confused. Right now I'm using a computer psu just taking the 12 volt line and ground.

 

[Bazukaz]

It is a simple car audio amp.Probably average in quality , since it is a B class amp.
Have you connected mute pin 14 to Vcc ?

 

[MikeB]

... the capacitors just remove the "noise" from the sound input. I should still receive some amplification. Replying to third post, what do you mean by the power supply. I'm a little confused. Right now I'm using a computer psu just taking the 12 volt line and ground.

No, that's not what an input cap is for, it's job is to block DC, in this case a quite large amount. By skipping them you force the input down to 0 volt, giving an inputvoltage of ~6v. No wonder the amp does not play... PSU = PowerSupplyUnit. You have a single supply, 0v and 12v. For the amp to be able to create AC at the ouput, it has to be biased to the middle of the supplyvoltage, 6v. You must use the inputcaps, they are not optional.

Mike

 

[kasemodz]

alright i placed 10uf capacitors in the input but it didn't do anything...still the same.

 

[MikeB]

Okay, looks like time to measure... First double check if all connections are exactly as in the plan. Have you connected inputsignal to IN and SIGNAL GROUND ? Then measure if your computer power supply is correctly giving 12v. Most computer power supplies have a minimum load. If it is a ATX supply, you need a special signal to power up the whole thing.
If the 12v are ok, measure the outputs to the speakers, pin 6 to 8 should measure ~0v, but these pins to gnd should measure ~6v.

Mike

 

[sagarverma]

check polarity of the caps.
-ive side to the i/p(bec its most likely that for 10uf,u would[will] be using polarised caps)

check i/p audio gnd connections to the gnd(suitably on the board)

if all this still doesnt work,double check for dry solder joints.


Mike,

tda1554q is not average sounding,its more than the value for money,with a good power supply it plays very well.

 

[DoomPixie]

I know this is an old thread but i'd like to revive it. I just found this and i have been haveing the same problem with my TDA1554Q amp im building, i will add the input caps and see if it fixes the problem but here is the bit that puzzles me, the amp runs PERFECTLY if i completely disconect the ground connections to the RCA sockets, but with them connected i have nothing, tried a simple lead to a stereo headphone style plug and pluged it into my mini disk player instead of useing the rca conectors / leads and same problem. amp sounds pretty good though, very impressed that such a small chip can make such good music and loud aswell!
Owen