"groundbus" is this right?

tim614 · 16th February 2010, 07:17 PM

Trying to figure out the groungbus thing, please point me on the right direction.

HollowState · 08:20 PM

Hi Tim, Nice drawing. You have the right idea...almost. I would make the following change. From the three large main filter capacitors, instead of looping the buss up and around to the input tube area, connect it from the middle filter straight across to the center area near the output tubes. The idea is to keep the buss line short and compact. Use a nice heavy piece of copper wire (#12). Make the chassis connection from the center of the buss to either where it is now or perhaps centered near the tubes. You only need standard hookup wire for this chassis connection btw.

One more observation, why not interchange the PS input capacitor to the upper position. This would slightly shorten the b+ supply line to the tubes as drawn now.

tim614 · 16th February 2010, 08:23 PM

One more observation, why not interchange the PS input capacitor to the upper position. This would slightly shorten the b+ supply line to the tubes as drawn now.
__________________
thanks HollowState!

i would but there's no room

chrish · 16th February 2010, 08:30 PM

What you need to do is think about the return currents flowing through the ground bus. You want to keep the high return currents from the power supply and power tubes separate from the small signal currents of your input tube. The best hint on the order to hook up the components to the bus is the order they are drawn on the schematic. In other words, grid leak for input tube, cathode resistor input tube, cathode bypassfor same, input grid leak power tube, cathode bias resistor poewer tube and it's bypass cap, then power supply filter capacitors... Keep the big power currents away from your small signal return currents.

Cheers

kavermei · 17th February 2010, 06:35 AM

Yes, best practice is to run the ground bus from the main capacitors to the output tubes first, only then to the input tubes, and finally to the input sockets. Basically, the way you wired the B+. This way, you keep the big currents away from the input stage.

If you choose to connect signal ground to chassis (=earth), it can be done either at the input (just use standard RCA sockets) or at the main filter capacitor (then you should use insulated RCA sockets).

Happy building!!!

jrenkin · 17th February 2010, 01:16 PM

what drawing program did you use? It looks useful.

tim614 · 17th February 2010, 02:02 PM

Quote:

Originally Posted by jrenkin

what drawing program did you use? It looks useful.

i just use paint.

kavermei · 17th February 2010, 02:12 PM

Quote:

Originally Posted by tim614

i just use paint.

It contains the word "pain"

jrenkin · 17th February 2010, 04:23 PM

Nuts, I was hoping it was something fancier. I like stuff like that, but I have enough to learn about tubes without adding how to use a paint program too

Nice job with paint

though.

16th February 2010, 08:18 PM	#2
HollowState diyAudio Member Join Date: Aug 2006 Location: Taxland, New Jersey	Hi Tim, Nice drawing. You have the right idea...almost. I would make the following change. From the three large main filter capacitors, instead of looping the buss up and around to the input tube area, connect it from the middle filter straight across to the center area near the output tubes. The idea is to keep the buss line short and compact. Use a nice heavy piece of copper wire (#12). Make the chassis connection from the center of the buss to either where it is now or perhaps centered near the tubes. You only need standard hookup wire for this chassis connection btw. One more observation, why not interchange the PS input capacitor to the upper position. This would slightly shorten the b+ supply line to the tubes as drawn now. __________________ "The supercomputer is technologically impossible. It would take all of the water that flows over Niagara Falls to cool the heat generated by the number of vacuum tubes required." ~ Professor of Electrical Engineering, New York University Last edited by HollowState; 16th February 2010 at 08:20 PM.

17th February 2010, 06:35 AM	#5
kavermei diyAudio Member Join Date: Jan 2005 Location: Lokeren, Belgium	Yes, best practice is to run the ground bus from the main capacitors to the output tubes first, only then to the input tubes, and finally to the input sockets. Basically, the way you wired the B+. This way, you keep the big currents away from the input stage. If you choose to connect signal ground to chassis (=earth), it can be done either at the input (just use standard RCA sockets) or at the main filter capacitor (then you should use insulated RCA sockets). Happy building!!! __________________ Never send a human to do a machine's job. --Agent Smith

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16th February 2010, 08:23 PM	#3
tim614 diyAudio Member Join Date: Jun 2008	One more observation, why not interchange the PS input capacitor to the upper position. This would slightly shorten the b+ supply line to the tubes as drawn now. __________________ thanks HollowState! i would but there's no room

16th February 2010, 08:30 PM	#4
chrish diyAudio Member Join Date: Oct 2003 Location: Sydney	What you need to do is think about the return currents flowing through the ground bus. You want to keep the high return currents from the power supply and power tubes separate from the small signal currents of your input tube. The best hint on the order to hook up the components to the bus is the order they are drawn on the schematic. In other words, grid leak for input tube, cathode resistor input tube, cathode bypassfor same, input grid leak power tube, cathode bias resistor poewer tube and it's bypass cap, then power supply filter capacitors... Keep the big power currents away from your small signal return currents. Cheers

17th February 2010, 01:16 PM	#6
jrenkin diyAudio Member Join Date: Nov 2007 Location: Denver, Colorado	what drawing program did you use? It looks useful.

17th February 2010, 04:23 PM	#9
jrenkin diyAudio Member Join Date: Nov 2007 Location: Denver, Colorado	Nuts, I was hoping it was something fancier. I like stuff like that, but I have enough to learn about tubes without adding how to use a paint program too Nice job with paint though.

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