Rod Elliot P3A Layout - Critics - Page 26 - 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 2nd July 2013, 09:39 AM   #251
diyAudio Member
 
Join Date: Sep 2010
Location: Quezon City
Default please criticize

My old layout (in the pic) showed no signs of oscillations under scope.

Is my new layout good? Or decoupling is too far?
Should I change my old layout into this?
Attached Images
File Type: jpg p3a-old.jpg (409.3 KB, 706 views)
File Type: png p3a.png (34.6 KB, 652 views)
  Reply With Quote
Old 2nd July 2013, 10:58 AM   #252
Bone is offline Bone  United Kingdom
diyAudio Member
 
Join Date: Jun 2004
Location: Dorset, UK
If it aint broke dont fix it!
  Reply With Quote
Old 2nd July 2013, 11:56 AM   #253
diyAudio Member
 
Join Date: Sep 2010
Location: Quezon City
I'm not fixing it, im improving it
  Reply With Quote
Old 2nd July 2013, 07:07 PM   #254
diyAudio Member
 
Join Date: Apr 2010
Location: Coffs Harbour
Quote:
Originally Posted by jlester87 View Post
..... im improving it
OK, then improve the thermal coupling between drivers and bias transistor so it doesn't take ages to stabilize and responds usefully to changes in dissipation.

According to the pics, you don't have a driver heatsink anyway, so what bias current are using now? You don't need to move much to allow better coupling with just a single heatsink for all 3 transistors, assuming you don't already have this arrangement but just haven't shown it here.
__________________
regards
  Reply With Quote
Old 3rd July 2013, 12:37 AM   #255
diyAudio Member
 
Join Date: Sep 2010
Location: Quezon City
Hi, the drivers will be connected on a single heatsink. Bias transistor and Q5 are thermally coupled (glued by thermal epoxy), thus changes in Driver transistor Q5 will be quickly monitored by Q9.

5W output collector resistors are on the underside of the PCB.
Attached Images
File Type: png p3a.png (32.0 KB, 594 views)

Last edited by jlester87; 3rd July 2013 at 12:41 AM. Reason: Added picture
  Reply With Quote
Old 3rd July 2013, 01:47 AM   #256
Bigun is offline Bigun  Canada
diyAudio Member
 
Bigun's Avatar
 
Join Date: Jan 2009
Blog Entries: 2
Nice layout - I also used this approach for my TGM1, TGM2 and TGM3 - having power rails on one side and sensitive parts on other side.
__________________
"The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.
  Reply With Quote
Old 4th July 2013, 09:30 AM   #257
diyAudio Member
 
Join Date: Sep 2010
Location: Quezon City
Thanks Bigun

What I liked with P3A(sziklai) is that only the O/P transistors are mounted on the main heatsink. This simplifies the work on the amp case. Also it has low parts count, so it is as easy to build as chip amps.
  Reply With Quote
Old 4th July 2013, 09:49 AM   #258
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
that is why this amp is highly recommended for newbies.....as well as oldtimers....
__________________
the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....
  Reply With Quote
Old 4th July 2013, 11:07 AM   #259
diyAudio Member
 
JOHN BALI's Avatar
 
Join Date: Jun 2010
Location: Near the Mountain
Hi Tony, where is the oldtimers
I must give it a try...
Quote:
Originally Posted by AndrewT View Post
The Power Ground does not need to be connected to the Signal Ground by using PCB traces.
The Power Ground and the Signal Ground need to be referenced to the same voltage. This can be on board, or it can be off board.

If you are building more than one channel into your amplifier, then I assert that the Main Audio Ground (where Signal ground and Power Ground meet) must be off board.
Quote:
Originally Posted by gmphadte View Post
John Bali
The big filter capacitors have to be located close to the power transistors in order to reduce the inductance added by the long track.

Gajanan Phadte
Quote:
Originally Posted by Bigun View Post
Nice layout - I also used this approach for my TGM1, TGM2 and TGM3 - having power rails on one side and sensitive parts on other side.
So many critics to my own layout, thanks guys...
time to improving it
__________________
Thank you, I wish you happy
peace & G B U
  Reply With Quote
Old 4th July 2013, 11:26 AM   #260
AJT is offline AJT  Philippines
diyAudio Moderator
 
AJT's Avatar
 
Join Date: May 2003
Location: Palatiw, Pasig City
Quote:
Originally Posted by AndrewT
The Power Ground does not need to be connected to the Signal Ground by using PCB traces.
The Power Ground and the Signal Ground need to be referenced to the same voltage. This can be on board, or it can be off board.

If you are building more than one channel into your amplifier, then I assert that the Main Audio Ground (where Signal ground and Power Ground meet) must be off board.

so many words....what does it amount to?

why can't AndrewT just show us in pictures what he's got so we can appreciate what he says....
__________________
the best advertisement for a good audio design is the number of diy'ers wanting to build it after all the years....never the say so of so called gurus....
  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
Rod Elliot P.68 Phase? samutacaratti Solid State 26 20th August 2014 03:39 PM
Rod Elliot P37? roger-k Solid State 21 7th October 2006 07:37 PM
Rod Elliot P3a boards stuffed FS! Mattyo5 Swap Meet 8 3rd October 2006 01:45 PM
Rod Elliot P3A amp noises tktran Solid State 2 18th March 2003 07:04 PM
Rod Elliot 100W PCB Layout bugbite2k Solid State 5 30th January 2002 05:32 PM


New To Site? Need Help?

All times are GMT. The time now is 04:46 PM.


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