Here is a partial quote from:
http://forum.metroamp.com/viewtopic.php ... 0&start=18
Trying to keep the ground points just under the edge of circuit boards for a cleaner look.novosibir wrote: There are some basical rules:
Think your ground points along a line across the chassis.
1-st come the inputs & V1 cathodes
2-nd come volume & V2 grounds
anywhere between 1 & 2 the preamp filter ground
3-th comes tone stack, V3 (presence), PI filter & speaker jack grounds
The OT's secondary common has to be grounded to the speaker jacks !!!
4-th comes the bias & screen filter's ground
5-th comes the rectifier ground (or HT CT), 1-st filter ground & output cathodes
6-th is the earth from the wall supply ONLY
Best (quitest) place for the heater CT would be 1-st ground spot, although a long way there. May put to 4-th, but NEVER 5-th
I've showed the 'ideal' above!
Do it simpler and have the risk of hum!
Larry
Here is the progress so far with points 1 thru 5 labeled:
Trying to keep the ground lugs tucked under the edge of the circuit boards for a cleaner look.
Closer look at points 1-4:
So far:
#1 - Heater common has been attached (Inputs and V1 Cathode to be added)
#2 - (Volume controls and V2 Cathode to be added)
#3 - PI filter ground has been attached (Tone stack, presence grounds, and speaker ground to be added)
#4 - Bias ground has been attached (Screens filter ground to be added)
Closer look at points 4 & 5:
#4 - Bias ground has been attached (Screens filter ground to be added)
#5 - Mains filter ground.