Help with Interference issue [resolved]

[Paul Birkeland]

The Hum Exists with the plug all the way in, but not if it's some of the way out of the plug as best I can tell.

If there was a cold joint, would this not cause voltage and resistance irregularities?

The only relevant test is with the plug all the way in, otherwise you short some connections together that give you erroneous readings.

A cold solder joint rarely shows up in resistance readings, sometimes will show up in voltage readings, but often enough appears in neither.

My test for a cold solder joint is to jostle the piece of equipment pretty roughly while I'm listening to it.  Cold solder joints will announce themselves with crackling or popping.  Of course, the easiest method to be sure is to reheat all your solder joints.

-PB

[networkn]

The only relevant test is with the plug all the way in, otherwise you short some connections together that give you erroneous readings.

A cold solder joint rarely shows up in resistance readings, sometimes will show up in voltage readings, but often enough appears in neither.

My test for a cold solder joint is to jostle the piece of equipment pretty roughly while I'm listening to it.  Cold solder joints will announce themselves with crackling or popping.  Of course, the easiest method to be sure is to reheat all your solder joints.

-PB

When you say piece of equipment I presume you don't mean electronic component? Touching things like capacitors and the like could be pretty dangerous I would have thought?

Given this is a buzzing rather than a crackling is the same solution recommended? Are there some components more likely to be causing that buzzing than others?

[Doc B.]

You use a non conductive tool to probe and wiggle the components. A chopstick works well. Anything plastic or wood that doesn't have metal on the end can be used to push on the various parts to see if it changes the sound. Use all of the proper safety procedures, support the inverted chassis so it is stable before you apply power, don't touch it with your bare hand.

[Horatio]

Bit of a wildcard but I spent two hours last night trying to troubleshoot a noisy Crack (static like buzzing even with nothing connected to it but headphones that I could overcome by cranking up the volume of the music) only to find that it was picking up interference from a Powerline Network Adapter I had plugged into a wall socket in the opposite corner of the room... With the Powerline Network Adapter unplugged everything was silent!

[networkn]

Hi There!

I wanted to post back and let you know I am now listening to a silent crack amp, after having given up and taking it to an electronics engineer I found in a local forum.

It took him about 20 minutes to find the problem and only after he went through step by step in the manual did he find that I had connected but failed to solder 2 of the connections on page 19 of the manual (I could get the numbers exactly of which tags, but it's on and would be hot to turn over. He summarized it was allowing a ground loop. It also explained why moving the amp to my office changed the sound as the car movement probably moved the connection slightly.

On the plus side he said with 1 exception he found my soldering to be better than a lot of the graduates with project work experience he had seen, he was pretty impressed.

It was a little frustrating to have it turn out to be this as I had been over the amp at least 20 times looking for bad solder joints but sometimes the more you look the worse it gets.

I am just glad to be over this hurdle. I am trying to now decide if I should listen to it more or move to the Speedball upgrade this weekend.

I am also wondering if there are other upgrades I should add now before the speedball which will be much harder once the speedball is in.

[Paul Joppa]

Wow - cool story, thanks for posting! Yeah, reality is like that - we've all been there, even if we don't always admit it!