Veroboarding a power amp - 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 19th March 2006, 08:42 PM   #1
diyAudio Member
 
Craig405's Avatar
 
Join Date: Jul 2005
Location: Sussex
Default Veroboarding a power amp

Hi,

I have been working too much at uni to do much diyaudio but now summer is coming i am going to build an Ampslab C200.1
http://www.ampslab.com/c200qc.htm

I pretty much have all the bits necessary but i cant make PCB's. I am therefore going to have to use veroboard.

I intend to box this amp up nicely and use it for a few years.

Is there anything about veroboard layout with power amplifier circuits i should know or may cause me later headaches (i cant take another oscillating amplifier ill go mad..)?

Cheers Craig

P.S.
Also has anyone listened to these amps for full range speaker use before?.
I didnt get much choice in the circuit because all my transistors are NPN and its the only powerful Quasi circuit out there.
  Reply With Quote
Old 21st March 2006, 04:11 PM   #2
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
Keep the layout as compact as you can manage. Don't have the power connections for the output transistors going to the board, connect these straight to your power supply. Similarly, hard-wire the power resistors R18-R21 and don't put them on the PCB. Put C9 and R22 across your speaker output terminals. Similarly have D3/D4 (flyback diodes) on the heatsink hard wired.

Keep compensation capacitor C7 as close to the transistor as you can. Ideally, the next hole along. C3 should be soldered right over R7 as well.

Shorten the tracks with a drill bit to exactly the length they need to be. Don't allow the unused track to carry signals, or it will act as an antenna and inject noise into your circuit which can make it oscillate.

If you are careful, you can make it work on veroboard. I managed to make an Elliot P3A works on veroboard and these use CFP output arrangements which can be very sensitive to layout especially with fast output transistors.

Are you sure you can't make PCB's though? Do you have a laser printer you could use? If you do its possible to make good quality PCB's at home for cheap using the Laser Toner Transfer method as detailed here - http://www.fullnet.com/u/tomg/gooteepc.htm
  Reply With Quote
Old 22nd March 2006, 09:48 AM   #3
diyAudio Member
 
Craig405's Avatar
 
Join Date: Jul 2005
Location: Sussex
Thanks for the tips!
Ill try and compress my initial layout plans and implement some of the capacitor positioning ideas you mentioned.

Cheers
Craig
  Reply With Quote
Old 22nd March 2006, 10:09 AM   #4
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi Jayce,
thanks for the tip
Quote:
Shorten the tracks with a drill bit to exactly the length they need to be. Don't allow the unused track to carry signals, or it will act as an antenna and inject noise into your circuit which can make it oscillate.
That link looks like a brilliantly detailed site for PCBs
__________________
regards Andrew T.
  Reply With Quote
Old 22nd March 2006, 10:32 PM   #5
diyAudio Member
 
geezer1944's Avatar
 
Join Date: Mar 2005
Location: usa
Howdy AndrewT,

http://www.fullnet.com/u/tomg/gooteepc.htm
is very detailed except for one little bitty thing.
It doesn't work very well except for the smallest of boards.
Press-n-Peel Blue is still the best product.
__________________
186,355 miles per second
It's just a rule.
  Reply With Quote
Old 23rd March 2006, 08:09 AM   #6
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
why only smallest?
__________________
regards Andrew T.
  Reply With Quote
Old 23rd March 2006, 02:06 PM   #7
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
It works just great for me. It's all in the paper you use.

Cheapo inkjet gloss paper just seems to leave a plastic backer behind which is useless. I use Kodak picture paper which is a bit more expensive but still a hell of a lot less expensive than PnP Blue. It has worked very well, requiring only a little touch up with a pcb pen sometimes, and no soaking in water other than to cool the board. I've made a 200x100mm pcb with this method.
  Reply With Quote
Old 23rd March 2006, 04:56 PM   #8
diyAudio Member
 
geezer1944's Avatar
 
Join Date: Mar 2005
Location: usa
To each his own method.
PnP works every time for me, small or 200x266mm board, .0325" trace up to a big fill area. No water soak, no tooth brush scrubbing, no mess or touch up. Tried more than 20 different "papers" (Kodak too)and dozens of heating "methods" that all failed in comparison. At best, the etching managed to under cut the traces and always left the drill holes filled with fiber. Even distribution and pressure of the heating platen seems to be the most important part of these transfer systems. Altho toner quality also plays a part. I want a pro looking finished product, so a bit more $ is not the criteria.
My granpa said always buy the best, you'll never be disappointed.
__________________
186,355 miles per second
It's just a rule.
  Reply With Quote
Old 24th March 2006, 07:46 AM   #9
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi Geezer,
are you saying it's not the size that is the limiting factor but the quality?

Very small pieces may have a higher tolerance to lower quality?
__________________
regards Andrew T.
  Reply With Quote
Old 24th March 2006, 04:56 PM   #10
diyAudio Member
 
geezer1944's Avatar
 
Join Date: Mar 2005
Location: usa
Hi AndrewT,
The temperature of your iron, quality of the toner, pressure applied, and many other factors are in play.
A board that will fit well inside the iron area has the best chance to give you a "useable" result. That means a relatively small board in my experience.
Folks say that this method works well and they are happy with it. Try it for yourself. I find it time consuming, clumsy and messy. It produces a not very good board compared to a production house board which is my standard. PnP comes closest to that.
When I want a really good self made board, I go back to the "old" method of hand coating the copper clad, exposing with UV, developing and etch. Now that's really messy.
Practical issue, an 8" x 10" production house board "prototype"will set you back about $30 each in quantity of 10. Buy 200 and they are about $10. Make your own, maybe $2.50 using "expensive" PnP.
To each his own.

Regards
__________________
186,355 miles per second
It's just a rule.
  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
40A 250V Schottky Power Diodes- Has anyone use in Power Amp to replace Diode Bridge? dtm1962 Solid State 10 15th September 2011 08:38 PM
Rockford Fosgate Power 20001 bd amplifier power rating?? pachoorion Car Audio 8 8th May 2011 11:49 PM
Power transformers versus amplifier output power..what is your option? destroyer X Solid State 38 9th May 2009 06:23 PM
Amplifier 3000 Wats Rms Power + Smps Higcht Power Bestiality MARAVILLASAUDIO Class D 1 5th November 2004 05:06 PM
power output calculations, rated power and required power output metebalci Tubes / Valves 7 22nd February 2004 06:49 PM


New To Site? Need Help?

All times are GMT. The time now is 02:39 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