Questions about grounding

dontellpapa · 10th November 2009, 03:53 AM

Hi all tube amplifier master,

I need your kind explanation about appropriate grounding in schematics.

The attached is what my diagram of tube amplifier. From the diagram, could you explain to me for #A through #F for what is going on?

Many thanks and bow to you in advance.

Regards,

Dontellpapa

aardvarkash10 · 10th November 2009, 05:22 AM

...schematic link?... or attach?

dontellpapa · 10th November 2009, 03:03 PM

pointy · 10th November 2009, 08:59 PM

from your main earth point take a (black)wire for "c+a"

and then an other (black)wire from your main earth point going to "f "first through to "a"
and then a bit of (white)wire from the "0 ohm tap on the out-put transformer" to point "a"

use about 1mm core wire (or may be a bit less)

try to make the white wire one strand of copper core wire

dontellpapa · 10th November 2009, 09:49 PM

Thanks Pointy for how to connect all groundings.

I need a help of understanding the logics of all groundings from a through f.

boywonder · 10th November 2009, 10:10 PM

dontellpapa: Search this forum for "star grounding"

As a general rule of thumb (for star grounding), to reduce hum, you want to tie all of the signal grounds to one common point, which may also be your safety ground, or use one connection to tie the star ground point to the chassis/safety ground if they are not the same point.

Another grounding scheme is buss grounding.

The objective with either scheme is to reduce/eliminate ground loops due to differing voltage potential at the grounding points.

Poindexter has a mini-dissertation on grounding and hum here (about 1/2 way down the page):

THE MUSICAL MACHINE; IMPLEMENTATION.

pointy · 11th November 2009, 12:26 AM

that was from f to a ........ anyway from your "main earth" to "f"
then from "f" to "e"
then "e" lastly to "a"
and don't forget to bring the white wire from "0 ohms tap of the out-put transformer" to "a" also

this is an old style of earthing and it's true you may find "star earthing" better

dontellpapa · 11th November 2009, 03:41 AM

Thanks for all your feedback above.

However, I wanted to understand the reason of the grounding in each location of the diagram above. At least I like to know when/where to place grounding from the diagram.

Thanks.

Dontellpapa

gyro · 11th November 2009, 12:09 PM

Just a quick non grounding related note on your schematic - the LED that you have shown on the primary side will die of excessive reverse voltage (max spec is around 4-5V). You need to put a diode in parallel with it with reverse polarity to prevent this.

AndrewT · 11th November 2009, 01:05 PM

Quote:

Originally Posted by gyro

Just a quick non grounding related note on your schematic - the LED that you have shown on the primary side will die of excessive reverse voltage (max spec is around 4-5V). You need to put a diode in parallel with it with reverse polarity to prevent this.

put the diode in series with the LED. That will drop the power dissipated in the resistor by half.

10th November 2009, 03:53 AM	#1
dontellpapa diyAudio Member Join Date: Oct 2009	Questions about grounding Hi all tube amplifier master, I need your kind explanation about appropriate grounding in schematics. The attached is what my diagram of tube amplifier. From the diagram, could you explain to me for #A through #F for what is going on? Many thanks and bow to you in advance. Regards, Dontellpapa

10th November 2009, 05:22 AM	#2
aardvarkash10 diyAudio Member Join Date: Mar 2007 Location: Auckland, NZ	...schematic link?... or attach? __________________ Yes, conservatism thrives on low intelligence and poor information. But the liberals in politics... continue to back off, yielding to the supremacy of the stupid. It's turkeys all the way down. - George Monbiot, guardian.co.uk, 6 Feb 2012

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10th November 2009, 03:03 PM	#3
dontellpapa diyAudio Member Join Date: Oct 2009

10th November 2009, 08:59 PM	#4
pointy diyAudio Member Join Date: Mar 2009	from your main earth point take a (black)wire for "c+a" and then an other (black)wire from your main earth point going to "f "first through to "a" and then a bit of (white)wire from the "0 ohm tap on the out-put transformer" to point "a" use about 1mm core wire (or may be a bit less) try to make the white wire one strand of copper core wire

10th November 2009, 09:49 PM	#5
dontellpapa diyAudio Member Join Date: Oct 2009	Thanks Pointy for how to connect all groundings. I need a help of understanding the logics of all groundings from a through f.

10th November 2009, 10:10 PM	#6
boywonder diyAudio Member Join Date: Jan 2008 Location: So.Cal.	dontellpapa: Search this forum for "star grounding" As a general rule of thumb (for star grounding), to reduce hum, you want to tie all of the signal grounds to one common point, which may also be your safety ground, or use one connection to tie the star ground point to the chassis/safety ground if they are not the same point. Another grounding scheme is buss grounding. The objective with either scheme is to reduce/eliminate ground loops due to differing voltage potential at the grounding points. Poindexter has a mini-dissertation on grounding and hum here (about 1/2 way down the page): THE MUSICAL MACHINE; IMPLEMENTATION.

11th November 2009, 12:26 AM	#7
pointy diyAudio Member Join Date: Mar 2009	that was from f to a ........ anyway from your "main earth" to "f" then from "f" to "e" then "e" lastly to "a" and don't forget to bring the white wire from "0 ohms tap of the out-put transformer" to "a" also this is an old style of earthing and it's true you may find "star earthing" better

11th November 2009, 03:41 AM	#8
dontellpapa diyAudio Member Join Date: Oct 2009	Thanks for all your feedback above. However, I wanted to understand the reason of the grounding in each location of the diagram above. At least I like to know when/where to place grounding from the diagram. Thanks. Dontellpapa

11th November 2009, 12:09 PM	#9
gyro diyAudio Member Join Date: Jul 2004	Just a quick non grounding related note on your schematic - the LED that you have shown on the primary side will die of excessive reverse voltage (max spec is around 4-5V). You need to put a diode in parallel with it with reverse polarity to prevent this.

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