Help with Interference issue [resolved]

[networkn]

Reflowing is just a matter of heating the joint until the solder turns to liquid again and adding solder only if you think it's needed.

As an example of what you are trying to fix in these cases, one of the resistors in my Mainline attenuator looked like it was soldered, but on really close inspection I found a "void" around one of the resistor leads at the joint. Reheating the joint allowed the flux and solder to reflow and this time to make full contact with both leads in the joint.

It's possible to have a "void" in the joint that you can't see so reflowing (making sure all the solder in the joint liquifies and flows) helps to remove any of these that might exist.

Thanks for the explanation. I figured it was that, but I thought I'd check to be sure.

[networkn]

Could someone please confirm for me that it's ok for those components to touch each other? I presume so since the Amp actually works and voltages and resistances are correct.

[Paul Birkeland]

Which components?

[networkn]

Which components?

Hi There!

I think they are diodes, the black ones in the pictures I posted. There is no metal pins touching other pins, but the diode parts are touching each other a little.

[Paul Birkeland]

The black bodies of the diodes can touch, that's OK.  You just don't want the metal leads on a pair of diodes touching when they go to different terminals.

[networkn]

The black bodies of the diodes can touch, that's OK.  You just don't want the metal leads on a pair of diodes touching when they go to different terminals.

Thanks, I was pretty aware that was likely so I am pretty sure that's the case, I'll double check tonight.

[networkn]

Boy oh Boy how the plot has thickened!

Turns out that the problem IS being introduced at the source, if the source is considered the ODAC connected between the Source and the Crack Amp.

I did the reflow and then if anything the problem seemed worse (settled back to normal badness after a bit).

I can't hear anything I would consider abnormal (A bit of staticy type noise when I move the volume on the crack just whilst it's moving) when the ODAC isn't present, but then the sound isn't as good. If I plug the ODAC into the O2 Amp I have, I can't hear anything, so it seems to be some sort of weird compatibility between the ODAC and the Crack.

I apologise for the incorrect information, it's been a few months since I last worked on the issue, and my memory of the troubleshooting has obviously let me down.

Should I start a new thread to address the potential issue between the ODAC and the Crack or just continue?

[Paul Birkeland]

How are you powering your ODAC?

[networkn]

USB. It's the only option.

[Paul Birkeland]

You might want to try getting a USB cable with an external power supply, or if you aren't already, try using a laptop running on its battery. 

[networkn]

Hi There!

Ok well, I plugged the ODAC into my laptop and it sounds AWESOME with the CRACK. No noise, nothing. Perfect. Seems there is an issue between the USB on my PC, the ODAC and the Crack.  The ODAC guy asked:

"If the Crack amp uses two independent grounds for each channel (rare), perhaps ODAC's common ground creates issues within the Crack Amp"

Is this possible/Likely or is it really now a case of figuring out why my PC USB causes the problem when it doesn't happen with another AMP or even with no amp?

On the plus side, I think this means I made no mistakes whilst building the crack. My grandfather (RIP) would have been so proud. It was him that introduced me to Electronics when I was 8, and bought me my first DIY Electronics kit, with strings instead of solder.

I have been trying to find a place that makes very nice little metal plates (Plaques) I can have laser etched, my dedication of the amp to him, in case anyone knows of a place.

[JamieMcC]

I have been trying to find a place that makes very nice little metal plates (Plaques) I can have laser etched, my dedication of the amp to him, in case anyone knows of a place.

You might try here

http://www.frontpanelexpress.com/

[Doc B.]

Crack uses a common ground between the two channels. Since your laptop is quiet (presumably running on betteries or maybe a two prong power cord) and your PC is not (presuming your PC is plugged ito the wall) there may be a ground loop issue. Is the PC plugged into the same AC mains outlet as the Crack?

[networkn]

Crack uses a common ground between the two channels. Since your laptop is quiet (presumably running on betteries or maybe a two prong power cord) and your PC is not (presuming your PC is plugged ito the wall) there may be a ground loop issue. Is the PC plugged into the same AC mains outlet as the Crack?

Hi There!

Sort of, My PC is plugged into a 4 Way Zap Catcher, and the Laptop was plugged into another 4 Way Zap Catcher, but eventually they end up in the same wall socket.  The Laptop probably is quiet as much because it runs from battery even when plugged in as I understand it.

How do I tell what is not grounded? Is there an easy test? If the Crack wasn't grounded, what would happen? Would it's fuse blow? I have the 240v version.

[networkn]

Well today I bought a Schiit BiFrost, and low and behold, with USB, the same noise. So it's not the Dac causing the problem. How do I work out if there is a ground loop on the Crack, or on my PC, or somewhere else?