Recognizing part maybe TVS diode?!

[Perry Babin]

I see a direct ground connection for primary and secondary. You have the amp, measure it.

 

[Lenin89]

I was referring "What if you insert a resistor (try various values up to about 1k) in the ground jumper?" do I need here only a resistor or a small film cap in parallel too, the way sometimes the primary gnd is separated from the secondary one in amplifiers. Do i have to mimic that ?

 

[Perry Babin]

The resistor isn't to mimic that. It's just to reduce the connection from 0 resistance to something similar to (but not a replacement for) the patch cords.

 

[Lenin89]

Using a resistor between 22 ohms and 1200 ohms gives out a nice clean sinewave with NO increased current draw. Anything more or less starts affecting the sinewave in some way.

Such a headache....for a simple resistor...

Thanks for solving my 3 repairs !!!

So what is the issue exactly ? Why does when the amp has a direct connection between the RCA shield and main gnd is increasing its current draw, but inserting a 22ohms<-->1000 resistor fixes this ?

 

[Perry Babin]

The input circuit has several small capacitors that are ultrasonic bypass capacitors. The straight connection may have made them less effective or could have been destabilizing the circuit.

 

[Lenin89]

Perry I really do admire Your knowledge. Sometimes it feels like You know everything.
You are like our master Yoda in this car audio section of the forum.
I've already bought your guide, but is there any other way we could support You for all the help you've provided to the community here ?

 

[Perry Babin]

No need for further support.

 

[ximikas]

Interesting finding, so problem is ground loop. What happens, if in parallel to these 22-100 ohms capacitor 1uf is installed?