maxime
Well-known member
hello,
I'm currently debugging my brand new G9. I was wanting to get advice about the grounding method of the unit as I suspect mine to have this problem.
noise level is about at -60dB at full gain, the tone of it being really hiss+ 50hz harmonics (I suspect it being ground hum?). I also noticed it to be greater on the channel 2 (more 50hz harmonics)
At the moment changing the toroids and power caps place doesn't affect noise figures, as getting one of the xformer opposite to the other. my pcb, jacks and regulators is also isolated.
I only have one terminal chassis ground (at the side of the input 1 xlr). a strap goes from this to all the pins 1 of XLR, and is solered at the other end at the power inlet ground. so, just as prescribed by Jakob, our master, so no star ground here...
What makes me wonder is the fact that all inputs and outputs at the pcb grounds are connected to the xlr first pin, so creating multiple paths from the pcb to the chassis, no? should it be better with only pcb in or out to be grounded?
also about the cables coming from power transformers. I twisted every pair and pushed those close to the chassis (just as in those guitars amplifiers). Is it the right way to do it?
should the audio cables be the opposite (in the air)?
Is there a rule about the subject?
many questions, many questions, many questions,....
anyway, I want to thank you all about this super project that is the G9, and also all the discussions around it
best wishes
maxime
I'm currently debugging my brand new G9. I was wanting to get advice about the grounding method of the unit as I suspect mine to have this problem.
noise level is about at -60dB at full gain, the tone of it being really hiss+ 50hz harmonics (I suspect it being ground hum?). I also noticed it to be greater on the channel 2 (more 50hz harmonics)
At the moment changing the toroids and power caps place doesn't affect noise figures, as getting one of the xformer opposite to the other. my pcb, jacks and regulators is also isolated.
I only have one terminal chassis ground (at the side of the input 1 xlr). a strap goes from this to all the pins 1 of XLR, and is solered at the other end at the power inlet ground. so, just as prescribed by Jakob, our master, so no star ground here...
What makes me wonder is the fact that all inputs and outputs at the pcb grounds are connected to the xlr first pin, so creating multiple paths from the pcb to the chassis, no? should it be better with only pcb in or out to be grounded?
also about the cables coming from power transformers. I twisted every pair and pushed those close to the chassis (just as in those guitars amplifiers). Is it the right way to do it?
should the audio cables be the opposite (in the air)?
Is there a rule about the subject?
many questions, many questions, many questions,....
anyway, I want to thank you all about this super project that is the G9, and also all the discussions around it
best wishes
maxime