Hi members...I started drawing my AM/FM radio board but I’m not an electronic engineer and now I need some help.... I’ll be very thankful for any comment.
The complete schematic is the file: AM_FM Car Radio.JPG
1) TDA1554Q:
For the tests I’m using only one TDA1554Q amp, the schematic is the same of the Aaron… www.aaroncake.net/circuits/amp20w.htm but as you can see my schematic uses two TDA1554Q.
The question is about the two 2200uF/25V elect capacitor, must they be placed as near as possible to the pins 5, 13 and 14?
I don’t have enough space to place the capacitors where I want, one of them will be placed near an IC and the other will have a 80mm track long to the IC.
2) LM1036:
I used the schematic http://perso.wanadoo.fr/crystalizer/preamp_diy/tcs.jpg and I’m having problem in how ...let’s say.... in how to match the input capacitors (pins 2 and 19) and the output capacitors (pins 8 and 13).
Today I tested with input caps=1uF and output caps=2,2uF but the sound breaks, then I tested with input caps=220nF and output caps=1uF but is not 100%good....should I use nano values for caps with good filtering?....any suggestion?
Thank you all,
Wilson
The complete schematic is the file: AM_FM Car Radio.JPG
1) TDA1554Q:
For the tests I’m using only one TDA1554Q amp, the schematic is the same of the Aaron… www.aaroncake.net/circuits/amp20w.htm but as you can see my schematic uses two TDA1554Q.
The question is about the two 2200uF/25V elect capacitor, must they be placed as near as possible to the pins 5, 13 and 14?
I don’t have enough space to place the capacitors where I want, one of them will be placed near an IC and the other will have a 80mm track long to the IC.
2) LM1036:
I used the schematic http://perso.wanadoo.fr/crystalizer/preamp_diy/tcs.jpg and I’m having problem in how ...let’s say.... in how to match the input capacitors (pins 2 and 19) and the output capacitors (pins 8 and 13).
Today I tested with input caps=1uF and output caps=2,2uF but the sound breaks, then I tested with input caps=220nF and output caps=1uF but is not 100%good....should I use nano values for caps with good filtering?....any suggestion?
Thank you all,
Wilson
Placing that supply decoupling capacitor away from the IC may cause parasitistic oscillation problems and unwanted AC currents flowing through the PCB tracks from the IC to the capacitor. Yoy should place this capacitor near the IC even at the expense of placing other components away from the IC. That capacitor may be placed at 8cm from the IC as long as you carry + and - tracks together and place in paralell a smaller capacitor near the ic [what you can fit here]
Input and output caps of LM1036 appear to be just for DC-blocking purposes so their value should not be critical. The problem that causes distorted audio is probably elsewhere
Input and output caps of LM1036 appear to be just for DC-blocking purposes so their value should not be critical. The problem that causes distorted audio is probably elsewhere
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