TDA2005 amp

[casiomax]

that hissing noise due to a reversed polarity on the input cap... I use polar cap, try to replace with MKT non polar, it worked, and put the input cap in reverse order, it worked!!.. but on the schematic it wasnt like that... hmmmm...

[J M Fahey]

Please post the "hmmmm"  schematic.

[Michiel]

Hello to everyone,

New on the forum. I was just reading about the tda2005 amp you're discussing here. The website is Dutch, and I'm from Holland, so if anyone needs an explanation of part of the text, or if you'd like me to ask the designer of the circuit a specific question, please let me know and I'll try to help out.
Great website BTW, I just finished an 2003 based amp this evening. Works like a charm, but very noisy when playing the lower strings. I'll try to figure out if this is a result of the 3 euro speaker I'm using or the absence of a preamplifier... But that should probably be in the 2003 amp topic I guess.

[J M Fahey]

Hi Michiel. Thanks for our translation services offer, Dutch isn´t easy. I´ve just registered on that site, but, really, I only clicked what I think is "yes" on forms I can´t understand.

[casiomax]

Please post the "hmmmm"  schematic.

Hi J M,

the hmmmm schematic bridge configuration i took from the datasheet, unless I am reading the schematic wrong, a polar cap sign with black and white stripe, should be read white= + polarity, and black = - polarity.

[J M Fahey]

Hi CasioMax. You´re reading the schematic right. As a general rule, considering it´s a (positive) single supply powered cicuit, polarized caps have their "+" side "towards the chip" and their "-" side "towards ground", either directly or through some resistor. The datasheet schematic is correct. The only exception *might* be C1: 2.2uF, from "Input" to pin "1", *IF* it does not go straight into a passive guitar (which would be a path to ground) but into a preamp which might be leaking some positive D.C. voltage into it. Measure the DC voltage on both pins of C1 just to be sure. Bye.