Star ground w/ Dual capacitor banks - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 28th September 2004, 08:41 AM   #11
sajti is offline sajti  Hungary
diyAudio Member
 
Join Date: Apr 2003
Location: Vác, Hungary
Quote:
Originally posted by traderbam
Interesting problem.
What I would do is dispense with the metal bars. Even though they are mechanically attractive. Run a separate ground wire from each cap to a central star post (could be a bolt thread). You'll need to do something similar anyhow for the + and - lines.

I don't see any sense in this.

This is not a good idea. To avoid the noise You have to separate the wire which goes to the amplifier, from the wire, which goes to the transformer.
I think the copper bar is good idea, but use the capaciotors in one group, and use one metal bar.

sajti
  Reply With Quote
Old 28th September 2004, 09:06 AM   #12
zeno is offline zeno  Europe
diyAudio Member
 
Join Date: Aug 2002
Location: Belgium
Best option is imo two bridges, rectify each winding separately.
The ground is connected to the - of one bridge and the + of the other. That gives you + and - and 0

Each voltageline than gets half of the capacitance.

In this way, the amplifier is not directly connected to the center tap of the transformer. And you only have one transformer, since you've already purchased it.

Check http://zero-distortion.com/start.htm

Marc
  Reply With Quote
Old 28th September 2004, 10:20 AM   #13
diyAudio Member
 
traderbam's Avatar
 
Join Date: Jan 2002
Location: Earth
Quote:
This is not a good idea. To avoid the noise You have to separate the wire which goes to the amplifier, from the wire, which goes to the transformer.
Sorry, I don't understand what you mean.
  Reply With Quote
Old 28th September 2004, 10:27 AM   #14
zeno is offline zeno  Europe
diyAudio Member
 
Join Date: Aug 2002
Location: Belgium
Quote:
Originally posted by traderbam
Sorry, I don't understand what you mean.

Check out http://www.tnt-audio.com/clinica/ssps2_e.html

There is no direct connection between the middle of the transformer and the ground of the amp.

Two bridges, two cap banks, +/- voltage. Connect left and right channel two one power supply.
If you want the ultimate channel separation, double the transfo's, four bridges, four cap banks.
A little bit more expensive...

Marc
  Reply With Quote
Old 28th September 2004, 11:25 AM   #15
diyAudio Member
 
traderbam's Avatar
 
Join Date: Jan 2002
Location: Earth
Yes, I understand what you are saying, Zeno, about configuring the rectifiers and dual secondaries. But I thought I was talking about something quite separate when suggesting individual ground wires to the star point.

Also, I don't understand what the "noise" related problem is when connecting the transformer centre-tap directly to the star point rather than using dual secondaries and combining +/- rectifier outputs at the star point.
  Reply With Quote
Old 28th September 2004, 11:36 AM   #16
diyAudio Member
 
Greg Erskine's Avatar
 
Join Date: Jan 2002
Location: Sydney/Australia
hi Killjoy99,

I'd tend to trust Rod's advice and go for 30,000uF but at least make it easy to switch from 30,000uF and 60,000uF and see what you prefer.
__________________
Greg Erskine
  Reply With Quote
Old 28th September 2004, 04:08 PM   #17
audioPT is offline audioPT  Portugal
diyAudio Member
 
Join Date: Aug 2002
Location: Right here
My contribution:
Click the image to open in full size.
  Reply With Quote
Old 28th September 2004, 04:26 PM   #18
sam9 is offline sam9  United States
diyAudio Member
 
sam9's Avatar
 
Join Date: Jun 2002
Location: Left Coast
There are a couple of sources (Slone, Self) that stongly advise against location the star gound at the PS caps. They clain this is a very noisy point in the circuit and using it as a star point risks creating a path for noise to enter the signal path.

An alternative would be to run suitable wire from the point between the caps to another point 4 or 5 inches away where you locate something such as heavy phenolitic terminal strip (or anything of similar function you find convenient). Then run wires from the power and signal grounds to the same point. This should also be used to connect the star point to earth. The idea, I think, is that the impedance to the earthing point as seen from the PS will always be less than to the PCB gound nets.

I hope I'm explaining this correctly and clearly. If not, I'm sure someone will post a claification.
  Reply With Quote
Old 28th September 2004, 04:43 PM   #19
audioPT is offline audioPT  Portugal
diyAudio Member
 
Join Date: Aug 2002
Location: Right here
I think I forgot to explain this:

The POINT of the cooper plate that is connected to the chassis is ONLY for the CAP's group.
The Center Tap of the Xformer and all other 'ground' wires, MUST be connected to the chassis in the same point (this is the real star ground).

This is my way to GROUND my amps

Rgds

Pedro Martins
  Reply With Quote
Old 28th September 2004, 10:45 PM   #20
diyAudio Member
 
traderbam's Avatar
 
Join Date: Jan 2002
Location: Earth
Quote:
There are a couple of sources (Slone, Self) that stongly advise against location the star gound at the PS caps.
That's enough incentive for me to put the star point as close to the psu caps as possible!

I'm not sure what they are talking about. What is absolutely crucial and the whole purpose of a star point is to avoid unwanted common loop currents within the same conductors. So all current flows that must not be shared within a common wire must be connected by separate wire to the star. All voltages are relative. So we simply define the star point to be the reference from which all other voltages are measured, including noise.

If you start fudging this with two star points you are much more likely to introduce unwanted intermodulation noise than reduce it, unless your conductors are at -273C. There is an old thread here somewhere where I explain this in more detail.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
star ground vs. ground plane Sebastiaan Chip Amps 15 10th May 2009 05:05 PM
Will this amp need a star ground? ghetto Chip Amps 3 25th August 2007 05:25 PM
Ground star JORGETronic Tubes / Valves 1 2nd June 2007 02:50 AM
Ground planes instead of star ground svokke Chip Amps 3 22nd October 2003 01:01 AM
Star ground naula Solid State 13 16th October 2003 07:43 PM


New To Site? Need Help?

All times are GMT. The time now is 05:15 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2