building amps

homertooties · 3rd December 2005, 09:35 PM

Hi all
has anyone built this amp i did very cheap to buy parts,what do you think can it be improved on

homertooties · 3rd December 2005, 09:36 PM

another pic

Cal Weldon · 3rd December 2005, 10:27 PM

I merged your threads.

edl · 4th December 2005, 09:23 AM

here you are

AndrewT · 4th December 2005, 10:45 AM

Hi,
the output stage bias depends on the diodes for voltage control.

If you keep the heatsink cold, then the bias could remain safe. But if the sink is allowed to heat up then the bias will increase and you could get thermal runaway in the output stage.

You have two components helping prevent this. Your 0r51 emitter resistors are very large and secondly the output has a very low quiescent bias due to only two diodes being used. You may be OK.

However a small modification will help. Move the two diodes to lie (glued) in contact with the heatsink. As the sink temperature rises the diode voltage falls and corrects the bias current in the outputs.

sousmielie · 4th December 2005, 12:11 PM

Hi,

I have built this amp a couple of years ago. It's very simple and easy to build and get working. I have built it with more output transistors, and changed the bias. I'll have a look at all the mods I have made and let you know.

This is a nice amp to begin with and is very cheap!!! Sound quality isn't too bad, mine has nice bass.

Cheers,
Werner

Leolabs · 5th December 2005, 01:34 AM

I remembered someone did build it without PCB.

3rd December 2005, 10:27 PM	#3
Cal Weldon Speakerholic diyAudio Moderator Join Date: Jan 2004 Location: British Columbia	I merged your threads. __________________ Next stop: Margaritaville Some of Cal's stuff \| Cal Weldon Consulting

4th December 2005, 10:45 AM	#5
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi, the output stage bias depends on the diodes for voltage control. If you keep the heatsink cold, then the bias could remain safe. But if the sink is allowed to heat up then the bias will increase and you could get thermal runaway in the output stage. You have two components helping prevent this. Your 0r51 emitter resistors are very large and secondly the output has a very low quiescent bias due to only two diodes being used. You may be OK. However a small modification will help. Move the two diodes to lie (glued) in contact with the heatsink. As the sink temperature rises the diode voltage falls and corrects the bias current in the outputs. __________________ regards Andrew T.

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
building Single Ended amps	akimball442	Tubes / Valves	3	7th January 2007 07:07 AM
New to building Amps	Jalex420	Solid State	6	3rd June 2006 04:35 AM
car amps are leaving the building...	Stuart Easson	Car Audio	0	7th November 2004 05:04 PM
Interested in building amps with Icepower modules	mattjk	Chip Amps	2	12th August 2004 09:47 PM
Newbie at Building Amps/Any Decent Books Out There?	barroter	Everything Else	7	25th October 2003 11:39 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read


	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

4th December 2005, 12:11 PM	#6
sousmielie diyAudio Member Join Date: May 2005 Location: GP (Gangstas Paradise)	Hi, I have built this amp a couple of years ago. It's very simple and easy to build and get working. I have built it with more output transistors, and changed the bias. I'll have a look at all the mods I have made and let you know. This is a nice amp to begin with and is very cheap!!! Sound quality isn't too bad, mine has nice bass. Cheers, Werner

5th December 2005, 01:34 AM	#7
Leolabs diyAudio Member Join Date: Dec 2004 Location: Bukit Mertajam	I remembered someone did build it without PCB.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)