Another g7 ground question!!!

read the metas. still have 2 questions. ht and heater grounds should be connected to chasis ground at the 7 pin xlr in the mic housing as per gyraf and others. but ioaudio writes in a thread,"just connect the three grounds (HT, Heaters & signal) together at the 7-pin xlr from the microphone. should signal out ground also connect to chassis ground??
also i have 2 of gustavs pcbs with trace errors mentioned in this thread
http://www.groupdiy.com/index.php?topic=566&highlight=g7+hum

i jumped the gap so no problem there. my question is this. the ht ground and heater ground are connected on the pcb by this trace,are they not? therefor,couldnt i make one connection from one of their respective pads to chasis ground, as they are connected to each other already? if not can someone explain why . i like to simplify if i can . thanks

In the G7, we feed heater current with it's own 0V line - XLR7 Pin7 - which is only connected to signal ground/0V close to the tube ("upper" end of the mic pcb).

PDF of the supply: http://www.gyraf.dk/gy_pd/g7/gic_psu.pdf

PDF of the mic: http://www.gyraf.dk/gy_pd/g7/gic.pdf

So the "real" 0V/Gnd is the one at XLR7 pin1.

And yes, signal gnd (and chassis) goes to pin1 as well - so does mains gnd (on supply box end) if you have gnd in mains.

In the mic, connect XLR7 pin1 (0V/Gnd) to chassis.

To sum up, use XLR7 Pin1 as star ground.

Jakob E.

hey, wait a sec. my pcbs does not look like that pdf file. heater 0V is not connected to ground at the "upper" end of the mic. the tracks dont meet. i made my G7 bout a year ago and it sounds ok. i dont have it here so ill have to check later. found this ol pic tho:

an american saying. "if it ain't broke, dont fix it" my pcb is the same, i jumped the connection but have not completed my mic. i'm ready to buff out the body and clear coat, then final assembly .to bad my pc sound card crapped out this week. need a new one.) i'll let "the board" know how it sounds.

That pcb edit is probably the latest one we've made, connecting gnd to heater-0V at the powersupply in stead of at the mic end..

Both will work just fine...

Jakob E.