improve sound quality and circuit?

[justin66]

hello guys i have been working on a dual tda1554q pcb it was my first project ever made with diptrace and in general i trusted auto router and experrianced a big fail so now im at a stage that i have to manually route everything and change some parts in order to make holes appropirate size anyways as i was looking at small industrial amplifyers i noticed that they have a lot more stuff including caps all so on
question number 1
in data sheet there is TEST circuit is that circuit is any good or is it just a basic circuit that will make IC work but dont expect good quality?

question number 2
how do i improve my design and reduce distortion ripple and ambient noise circuit is in attachment (dont look at pots i will fix them the general thing is quality ripple and input noise reduction)

question number 3
any alternative program for better manual routing?

question number 4
how do i find out in library witch component is right size because caps are definitely not right size

question number 5
how do i know what to upgrade in order to gain better results in audio quality also circuit in data sheet specify to filter input with small ceramic cap why does most of circuit on google chane them to bigger electrolytic caps

question number 6
i found really confusing pin that is mute some circuit just leave it on but some connect it throw resistor or caps why (assuming i want amp to be always on)?

i consider myself noob in electronics compared to David but i know basics no refinements or fancy ticks thanks in advance for helping me out

 

[picandmix]

Cannot find any datasheet with a pcb layout for that chip, but as to if you can use it  don't see why not, they are not going to publish a layout that does not make it perform worse .

Looking at web examples of those amps its really all about the heatsink and power supply which really control its performance, given the pcb layout and preamp is sensible.

Cannot help you with that pcb design suit but have at look at this site which is a wealth of good audio projects and information , and he has a few very similar ic amps that should give you some good general guidance.
His kits/pcbs are also very good quality, have used them myself.

http://sound.westhost.com/projects-0.htm#pwr

[justin66]

thanks do you know anything about that mute/standby pin on IC if it has or has not have to be connected in order to tun an amp

[picandmix]

thanks do you know anything about that mute/standby pin on IC if it has or has not have to be connected in order to tun an amp

Seems you have to pull it up to + to allow the amp to play, as most circuits show.

The capacitor is used to initially keep the mute low,  ie on, so the amplifier power on surge does not 'thump' the speakers.
Within a second or so the capacitor charges fully to +  via the resistor and the mute turned off.

[justin66]

A1. Generally you want to stick with the test circuit, and work on external schematics. Unless you think you are better than NXP's FAE.
A2. The channel separation will be sick due to R4 and R5.
A3. I prefer Altium Designer.
4. I draw every component's footprints myself.
5. Use film caps. Ceramics caps has piezoelectric distortion, electrolytic caps have shorter life as well as higher leakage.
6. I can not answer this. You may want to download a SPICE model for the chip, and run a simulation.

thanks for the tips i will look forward altium
talking about Q2
those resistors should be same nominal my goal here is to make one tda drive two subs in same box but they are a bit diffrent so i have pots that i can adjust their individual volume and the second tda drive stereo speakers thats why i dont want just short out pins oh and as im writing this i realized that those resistors may be for opamp i suppose its like a little amplifyer to right? i predict you will say its not good yes? how do i improve it. btw there is original circuit that im working from

[Zero999]

That circuit is much easier to read.

The old LM358 was never designed for audio. It's too slow and noisy.

Replace it with the NE5532 which is much better.
http://www.ti.com/lit/ds/symlink/ne5532a.pdf

[justin66]

thanks do you know anything about that mute/standby pin on IC if it has or has not have to be connected in order to tun an amp

Seems you have to pull it up to + to allow the amp to play, as most circuits show.

The capacitor is used to initially keep the mute low,  ie on, so the amplifier power on surge does not 'thump' the speakers.
Within a second or so the capacitor charges fully to +  via the resistor and the mute turned off.

thanks for the reply thats a brilliant idea thats why my previous amp that is no longer working was doing that speakers get like full 12volts for a second and why my pc speakers dont do that

i have an other question those chips experrianced a disastrous circuit witch one of the traces burned off (thanks for diptrace auto router and me being noob) how do i check if they are still working was there any chance that it could have damaged the chip? it was releiatively high current switching PSU from an old pc (12v)

[justin66]

The original circuit assumes zerosource impedance. Your circuit uses 2 pots to attenuate input signal, which introduces impedance. Therefore the crosstalk can happen, especially your input pot is at midspan.

ok the setup will be like this
one tda drive two 8ohm 7w speakers
an other tda is going to drive two 4ohm speakers about 20w each

what is zerosourse ? is it like 0R output or something?

what should i change what can i do diffriently because to be honest i didnt completely understood what do you mean because my english sucks at some point

[picandmix]

What exactly are you using those two amps and two sets of speakers for ?  and where does the sound input come from,  a MP3 player or PC sound card ??

[justin66]

What exactly are you using those two amps and two sets of speakers for ?  and where does the sound input come from,  a MP3 player or PC sound card ??

in sound loudness i dont see a big diffrerence between both but mainly its gonna be a pc and a phone sometimes its used like this
2 subs (4ohm) in one box driven with low pass filter (mono) and 2 mid range 8ohm speakers (stereo)