Hello.I built a small mono audio amp with an 8 pin TDA2822. The schematic isin this document ( on page 6,labelled "bridge".This is the problem: it starts working normally, but at a certainpoint, the speaker starts buzzing and rustling, at first very quietly,then louder and louder. A few seconds later, the noise gets quieterand quieter and then vanishes.It does this thing with and without the input connected.Today I noticed that I can stop the noise, or worsen it, by touchingand twisting the power cable. The power cable is just an extension Imade to bring power from a PC power supply to the board (+12V, +5V andGND, as my board also contains other circuits). If I connect the PSUto the board directly, it gets worse (more noise).What do I do?

OK, you said "I built", how did you built it ??PCB board, peg board, point to point wiring ??How did you build it ??Please post a pic somewhere.hamilton

Must touch power cable to stop noise?!

Feb 25, 2012 23 Replies

Rate this thread:

NT 14 years ago

You are silly. There was no data to open or save.

Its working to day though - 100uF decoupling is rather small, try

1000uF.

Vote

Michael A. Terrell 14 years ago

PLONK.

You can't have a sense of humor, if you have no sense.

Vote

Slater 14 years ago

Thank you Mook for the precious advice!

Vote

josephkk 14 years ago

Geez, put some power supply bypass caps on the boards, preferably near = the ICs you are using.

?-)

Vote

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required