Hi, i want to build a small chipamp for my shop & i like to try Tda1557Q but i'm confused about pin 12 (Input reference voltage?). Also should i connect pin 11 directly to +VCC or using resistance between is advisable? Value? There are many schematic on the net but i'm not sure which one to follow for best result. As power supply i have a 12V 3A transformer.
Last edited:
Seeing as both the amplification channels within the chip have differential inputs, pin12 connects to the negative inputs of both channels. However, since its driven internally by a voltage source, its best left unused (i.e. unconnected).
Try 10k from pin11 to VCC initially, if the amp doesn't switch on, lower it to 1k.
TDA1557Q has insanely high gain for a chipamp (X200) and as a consequence its input sensitivity is high (~60mV for full output) and its output noise also correspondingly high.
Try 10k from pin11 to VCC initially, if the amp doesn't switch on, lower it to 1k.
TDA1557Q has insanely high gain for a chipamp (X200) and as a consequence its input sensitivity is high (~60mV for full output) and its output noise also correspondingly high.
Alright but in most schematic pin 12 connect to ground via a 10-100uf capacitor. Despite its topology, high gain & noise it sounds very good if i recall correctly. Anyway i thank you for your advice.
Last edited:
Excellent! I have LM3886 & such chipamps but why use those in noisy environment, tda1557q will work for me.
Interesting to note that on TDA1552, pin12 is 'NC' - no connect. There is no external connection to the commoned negative inputs of the two amp channels.
I suspect that the reason these chips sound better than LM3886 is down to their superior PSRR in the higher frequencies.
I suspect that the reason these chips sound better than LM3886 is down to their superior PSRR in the higher frequencies.