Mod Questions

[BZ58]

Here's a couple more views. The yellow wire is from the C-X7 inductor soldered to the safety ground lug.

[Paul Birkeland]

Did you read up about how the temperature is adjusted on your solder iron?  As I mentioned before, I have the same iron, and it's easy to end up thinking you're cranking up the temp when you're actually calibrating the soldering iron by accident.  This is consistent with your complaints about not being able to heat the joints up enough, and it looks like maybe the flux still isn't flowing all the way. 

[BZ58]

Yes, thanks, I did read up on that and as a result I touched up some connections.

From the pictures I provided, does everything look ok?

Do I have the right settings on the multimeter to read the resistance?

Does the fact that I have 0 resistance point to any particular connections?

[Paul Birkeland]

A short between ground and either OA or OB usually indicates that the TIP50 transistors are not properly mounted to the heatshiks.

A reading of "OL" would be OK though.

[BZ58]

Everything looks good, voltages correct, all led’s glowing, but when listening there is no sound in the right channel.

I’ve discovered that when I pull up and down from the top of the right RCA plug (that connects to the DAC) it has about 1/8” give. The nuts on the bottom are tight. I can pull up and down on the soldered connection from the bottom also. Does that make any difference? Is it somewhat normal? If not is there any way to tighten this? Might this be the reason for no sound in the right channel?

[Paul Birkeland]

It could be.  You could temporarily solder a jumper wire between the center post of the left and right RCA jacks to see if that brings back the right channel.  If so, then I'd replace that jack.

[BZ58]

I changed to another RCA cord that I had and it worked, problem solved.

Another issue. Background hum. I solved it by plugging in the crack to a different outlet using a heavy duty extension cord that I was using for the Christmas lights. I tested it a few times to make sure, and it's a night and day difference. By the way, the extension has one female plug on one end. I don't know the specifics of the watts, etc. of the cord, but the Crack is perfectly silent now. The Crack was plugged into the same outlet as the iMac. The iMac is plugged into a surge protector power strip. On the other side of the wall is the outlet where the TV is plugged in. Now when I use the Crack, a cord is running across a doorway to another outlet.

Question is, is there something I can buy to interrupt whatever is causing the hum? This would enable me to plug the Crack into the same outlet as the computer. I don't know the terminology of what I'm trying to say, so I hope you understand my question. 

[Paul Birkeland]

You could try a small isolation transformer.  Something between 160 and 500VA should do the job.

[BZ58]

After searching this forum and others I’m not sure exactly what I should be getting.

Would this work well enough
https://www.amazon.com/XtremPro-Hi-end-Ground-Isolator-High-fidelity/dp/B01A56CMUO

Or do I need this “Isolation Transformer 120V Compact Power Line Conditioner 250Watts with Faraday Shielding and Filter (AV-250)”
https://www.amazon.com/Isolation-Transformer-Conditioner-Shielding-AV-250/dp/B07595XJ3N/ref=cm_cr_arp_d_product_top?ie=UTF8

There is another version that is an “Isolation Transformer 120V:120V Compact Power Line Conditioner 500Watts with Faraday Shielding / Eliminating EMI/RFI noise (AV-500)”.

Thank you for your patience answering the many questions!

[Paul Birkeland]

The second item is a good selection.  The additional cost of the 500W model is so minimal that I'd shoot for that!  If it doesn't work for you, save the packaging for it, as I might be interested in buying it from you.

[BZ58]

Solved the ground loop problem by using a three prong to two prong adapter. Sounds great! Is this a safe solution?

Please take a look at these pictures to see if anything is causing the ground loop.

(edit: having issues uploading pictures, but this one shows most of the wiring)

Thanks.

[BZ58]

Here's another picture.

[Paul Birkeland]

The three prong to two prong adapter isn't the safest alternative.  There are inexpensive outlet testers you can buy that have 3 lights on them to test the wiring of your outlet, it's probably worth testing the outlet you're currently using to see if it's wired properly.

If you have the Crack plugged into the outlet where your computer is, but you feed the Crack from your phone, is the noise present?

[BZ58]

Thanks, I’m going to get one of those outlet testers.

Noise is not present when plugging into the outlet where the computer is and feeding crack from the phone.

[Paul Birkeland]

This is a very common problem with using the headphone jack on a PC.  An independently  powered DAC, especially when used with a toslink cable, will eliminate that noise. 

-PB