Please comment my P3a PCB - 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 10th March 2011, 10:09 PM   #1
Joku is offline Joku  Finland
diyAudio Member
 
Join Date: May 2009
Default Please comment my P3a PCB

Hi,

Just made a board for P3a, I made both versions for single pair one that has the emitter resistors on board for using two pairs. In the version with two output pairs the driver transistors are MJE15034/5 and the VAS stage is MJE350.

Thoughts? Personally I like the one with single output pair more, the one with two pairs feels like a mess.
Attached Images
File Type: png P3a.png (48.3 KB, 200 views)
File Type: png P3a_twin_pairs.png (76.4 KB, 190 views)

Last edited by Joku; 10th March 2011 at 10:16 PM.
  Reply With Quote
Old 10th March 2011, 11:15 PM   #2
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
Hi

The orientation of the TIP3055 is backwards which would make it difficult to mount to a heatsink. Also it appears you are missing an output coil. Amplifiers with a global feedback loop taken from the output needs to have a coil in series from the output to the speaker to block RF from entering the feedback loop and causing instabilities. Wrap a 1/2W 10R resistor with 22Ga wire and attach it at both ends to the resistor. Place it in series with the output.
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 10th March 2011, 11:24 PM   #3
Joku is offline Joku  Finland
diyAudio Member
 
Join Date: May 2009
Ah well, I haven't meant to mount the TIP3055/2955 directly to the PCB, I just used them as connectors for Eagle. The output transistors (usually TO-3) would be attached to heatsink and be connected to PCB via wires.

Also, this design is from Rod Elliott, and he didn't use a coil to block RF from speaker, I don't know why. Maybe the cap & resistor to ground take care of that? Anyways, I have built the amp, and it works.

60-80W Power Amplifier

Last edited by Joku; 10th March 2011 at 11:32 PM.
  Reply With Quote
Old 10th March 2011, 11:33 PM   #4
Account disabled at member's request
 
MJL21193's Avatar
 
Join Date: Mar 2007
The output inductor (coil) is a good idea. It also protects your amp from capacitive loads.

Not sure why you have the ground trace in a big "u" around the board - you might want to cut it back to the last component it picks up.
  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
Please comment my pcb P3a roly3055 Solid State 53 8th June 2012 08:36 PM
please comment my pcb east electronics Solid State 75 10th November 2008 02:32 PM
please comment my pcb east electronics Solid State 15 28th July 2008 08:24 AM
P3a HELP(Please comment my PCB? thanks!!) MTO audio Solid State 2 23rd August 2007 09:04 PM


New To Site? Need Help?

All times are GMT. The time now is 06:58 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