Added a DAC, added a hum. Suggestions?

[richidoo]

I guess I'm not ready to take over completely yet. Just wishful thinking by a rank amateur, and I apologize for moving on your territory, Bill.

Yes, dedicated line is very good. But if it still hums, remember, you can always use the ground buster on the dedicated line too.... 

[lonewolfny42]

Bill...

I'd be happy to help Gene because he's such hapless fellow

Plus....It's his birthday....

[eleazar]

 

Bill...

I'd be happy to help Gene because he's such hapless fellow

Plus....It's his birthday....

I treat him no better than my own family. I forget their birthday's too. 

[etcarroll]

Eureka !!!!!!!

Richidoo's friend Sol proposed a fix for my hum - and it works!!!

Life is once again good.

[shadowlight]

Eureka !!!!!!!

Richidoo's friend Sol proposed a fix for my hum - and it works!!!

Life is once again good.

What was the solution? 

[etcarroll]

Adding 2 small diodes soldered together with a resistor bridging them, then adding that tidy package to the IEC - at the ground line of IEC I believe.

[richidoo]

The DAC was silent in my system before mods, so there's nothing wrong with the EE DAC. But there is a loop between Gene's DAC and the preamp wethinks. There are probably other ways to fix it, but this was mentioned as the cheap and easy way based on Gene's description of the problem. The hum is gone with a cheat plug, so Sol designed a simple circuit to go between IEC ground pin and chassis that conducts above 1 volt for safety, but does not conduct below that, to stop the hum in mV range. Quiet and safe, and many big name manufacturers use this circuit.   Now Gene's DAC is hum proof in any system!

[shadowlight]

Nice.  Good to know for future reference.