Super Regulator, collecting the facts - Page 8 - diyAudio
Go Back   Home > Forums > Amplifiers > Power Supplies

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 7th October 2003, 02:02 PM   #71
jwb is offline jwb  United States
diyAudio Member
 
jwb's Avatar
 
Join Date: Mar 2002
Location: San Francisco, USA
Send a message via AIM to jwb
GOsh, that seems sort of odd. I try to put the regulator adjacent to the regulated circuit, not 20 or 50cm away.
  Reply With Quote
Old 7th October 2003, 02:40 PM   #72
Banned
 
Join Date: Feb 2002
Location: As far from the NOSsers as possible
I'm not gonna touch this one.............

Jocko
  Reply With Quote
Old 7th October 2003, 04:31 PM   #73
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
The thread just died when Dimitri and I asked this.

Not even Fred has a practical suggestion

If the pcb is 200 mm or more AND there are several power consumers and we don't want (or can afford, space money cost) one regulator to each opamp or whatever.

Can Jan or anyone else suggest and practical solution?

My personal choice would be R+C.
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  Reply With Quote
Old 7th October 2003, 06:46 PM   #74
diyAudio Member
 
jan.didden's Avatar
 
Join Date: May 2002
Location: Great City of Turnhout, Belgium
Blog Entries: 7
Quote:
Originally posted by dimitri
Let us consider typical preamp (mixer, RIAA, mic). We try to place active circuit board as near as possible near the input jacks, we even make gain control spindle longer. We try to place xformer with rectifier, caps and regulator as far as possible from the input jacks. What will be the length for dc supply wires, including pcb conductors? Ok, don’t like 50cm, ok, 20 cm. Somebody in this thread speak about square mm of pcb conductor and uV. How can we compensate wires – by 4 wire circuit, but what will be when we try to feed
multiple ICs? We don’t need ultimate parameters for two specific nodes on the regulator output, we need good parameters for the whole supply rail.

I personally use 4 wire circuit for the output op-amp, because I have now idea what it load will be. Other op-amps feed through RC filters, but I try to switch their output stage in class A (or to use op-amp with appropriate quiescent current). When I don’t have cost restriction I use precision regulator with normal bipolar output stage (not the single follower) operating in class A with quiescent current value higher, than will flow in the circuitry.
Dimitri,

That's all fine and dandy, but the fact remains that you claimed to measure regulator performance where you actually didn't.

Now, to your post: Indeed, take the typical RIAA etc. One stage, two stages? How close are the supply points of those two stages? 1/2 inch apart? How close can you place the regulators? Anothe 1/2 inch away? Total 25.4 mm give or take a few angstrom. A far cry from 500 or 200 mm.
And come on, give me a break. We didn't talk about how far the xformer was away. As far as I am concerned, that can be in the next room. We were talking about the regulator distance.

But, apart from being a story that isn't holding water, it also has no bearing on the original issue. You'll have to do better than that.

Anyway, I'm sure you know the score. I'm not going to spend any more time on this thread explaining the obvious. You have the last word.
Or maybe Per-Anders

Jan Didden
  Reply With Quote
Old 7th October 2003, 06:47 PM   #75
diyAudio Retiree
 
Join Date: Oct 2002
Location: Spain or the pueblo of Los Angeles
Default Start with ohms law.........

"we need good parameters for the whole supply rail."

Power distribution is the same principle as single point grounding. The first thing is to determine which circuits are the most sensitive to power supply noise and put them close to the central hub of single point ground and power supply plus and minus voltage outputs with short traces. Segregate large power supply signal currents from sharing common traces with sensitive low current signals. Using separate power supply traces to each device when possible is a very good idea. It keeps signal currents from sharing a common trace impedance, which creates an error voltage that is common to both devices, and is a function of both devices power supply currents. This from their separate signal currents across a common trace impedance. Designing for low crosstalk from currents is the key. Think of the voltages at each device's supply terminals in terms of signal currents and the trace resistances through which the currents travel from the point of low impedance output of the supply. RC filters are effective at filtering noise from the central supply but are real compromise since signal currents through series resistors will cause variations in voltage at the device drawing the signal currents. The biggest mistake is not understanding the supply currents to each device's supply terminals, and failing to plan the ground and supply path before the rest of the audio circuit's placement. The circuit should be built around the power supply distribution early in the layout process. You cannot go add the power distribution afterwards. This sounds a little abstract and you need apply it to the particular circuit you are designing.

A couple of good references are:

http://www.analog.com/UploadedFiles/...8865AN-202.pdf

POWER UP:
An Overview of Power Supply Considerations
R.N. Marsh The Audio Amateur 3/83
  Reply With Quote
Old 7th October 2003, 06:55 PM   #76
diyAudio Member
 
Join Date: Sep 2002
Location: Sweden
Thanks, Fred, that makes perfect sense to me. Don't know why
anybody would find it abstract though?
  Reply With Quote
Old 7th October 2003, 07:16 PM   #77
jwb is offline jwb  United States
diyAudio Member
 
jwb's Avatar
 
Join Date: Mar 2002
Location: San Francisco, USA
Send a message via AIM to jwb
Because grounding is hard. Sometimes you won't even realize the problem until you've built the prototype and measured it. How best to wire power rails and grounds? When is a ground plane good and when is it a disaster? etc.

That, and the members of this board are generally unable to apply Kirchoff's Law.
  Reply With Quote
Old 7th October 2003, 07:16 PM   #78
jcarr is offline jcarr  United States
diyAudio Member
 
Join Date: Jul 2002
Location: Tokyo, Japan
Nice post, Fred.

Very similar approach to how I design pcbs and harnesses. As much as possible (when it makes sense), I feed each block of amplifier circuitry from its own regulator. When this isn't feasible, I get rid of every shard of common impedance that I can ferret out. And when separate regulation is feasible, I still do the same.

regards, jonathan carr

PS. I normally keep each regulator no more than about 8mm away from its load, and I also use local bypasses (lots of 'em).
__________________
http://www.lyraconnoisseur.com/, http://www.lyraaudio.com
  Reply With Quote
Old 7th October 2003, 08:01 PM   #79
diyAudio Retiree
 
Join Date: Oct 2002
Location: Spain or the pueblo of Los Angeles
Default Because grounding is hard.

It can be just that. I did a two layer line card. (low cost! 4 layers with ground plane would have got me fired) The grounding required digital, analog, transient (10s of amps), RFI and ESD grounding. The only thing missing was coffee grounds.

The grounding strategy could not quite be single point ground and had to share some common traces. I spent a long time thinking very hard about return current path, in order to avoid my boss having grounds to fire me. I never have pulled it off if I wasn't doing it with the best PCB designer I will ever get to work with. He could tell what I wanted, even when I couldn't quite explain it while sitting next to next to him in front of the monitor. You will never see me that grateful again for someone that talented to work with.
  Reply With Quote
Old 7th October 2003, 08:33 PM   #80
Electrons are yellow and more is better!
diyAudio Member
 
peranders's Avatar
 
Join Date: Apr 2002
Location: Göteborg, Sweden
Blog Entries: 4
It's allways a pleasure to let pros do the work for you. My "pro" is a toolmaker for plastic molding. He knows molding tools which I don't.

Fred, may I ask what the pcb did? The application?
__________________
/Per-Anders (my first name) or P-A as my friends call me
Super Regulator SSR03 Group buy
  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



New To Site? Need Help?

All times are GMT. The time now is 03:33 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