Amp 6 Basic has subtle constant static

[thejuddernaut]

Hey.
I built an Amp 6 Basic about 6 months ago and just now am getting around to powering it with a proper transformer and power supply rather than the smps that I was using. Ever since I first completed the project, there has been an audible white noise in the background. It all but disappears during loud passages, but is just audible enough in the quiet parts to cause me some serious stress. I thought powering it properly would help to eliminate this noise, but it actually seems to have gotten worse. Does anyone have any ideas about how to solve this problem?
Thanks a bunch,
Jud.

[krilli]

These amps are usually pretty quiet. And usually when there is noise, it's a simple fix - the amp is 99.9% working, there's just a small crack in the dam that's letting noise in, so to speak.

I would check the output filter soldering.

Do you have a reasonably good camera? - Could you maybe post a picture of the board? There are some eagle-eyed people on this forum!

[gnome]

I'd start by isolating the noise by hooking it up to a 12v battery, if the noise is still there then it is the amp, if it goes away then you know it is the power supply.
"usually pretty quiet" is a bit of an insult :P, the thing is jaw droopingly quiet. Hooking it up to 106dB speakers, there was just nothing.
Could also be your source, try different ones.

[thejuddernaut]

Alright Guys.
I tried some different power supplies with no real change. It very well could be my soldering. This was my first time with surface mounted parts and although I feel like I did pretty well, I could have made a minor slip or something. Here are some pics. Please let me know if anything seems obvious.
Thanks for all the help thus far,
Jud.DSC01152.jpgDSC01153.jpgDSC01154.jpg

[tuo]

It seems that you have used too much solder with your SMD components. And the output filter inductors does not seem the be in level with the PCB, which means there's solder under them and that might lead to a cold joint. Best way to solder those components is to add a little bit of solder on one pad, heat it up and place the component tightly on the board. When the first pad has cooled, the component will stay there and it is easy to solder the other pad(s) as well.

Now for removing the excess solder you can use solder wick.

Here are some pictures for reference: http://www.41hz.com/forums/entry.php...6-BASIC-SNEAKY

HTH

[krilli]

Couple of points - Leaded solder is good, lead-free bad ... 50W+ iron good, 30W pretty bad. I had to get a new iron the other day when my 50W died, I went for a 30W one to see what it was like, and it's way more difficult to get good joints! The warnings about the thick copper plane in 41hz gear are there for a reason. Ended up getting a 60W iron for the bigger joints, of which there would be a few on the AMp6.

So check your tools - The joints here could stand a little improvement overall, and the tools do make a great difference!

Sorry if I?m saying stuff you know ... It's just that as I learn more about soldering, the more I see how easy it actually is and i'd have liked to know that sooner!