Brian GT chip amp build Questions

guycom · 6th February 2008, 08:33 PM

Hi, I am building my first amplifier and had two questions. How do I know if the led is positioned correctly? Second I have a large iron core transforme with three secondery wire-- ca I shre the cener tap with both boards.
Thank You for your help,
Guycom

wboyd · 6th February 2008, 08:51 PM

I believe that long tail of the LED is the pos terminal....don't shoot me if I am wrong....but it is listed somewhere in the manual. I think that there is a marking on the PS board showing where the long tail is supposed to go.

As for your transformer situation...I have a question for you. Are you saying the the transformer has 3 secondary widings (6 wires), or it has 3 wires coming out of it (ie 2 colored wires and common). If the second situation is the case then there is a certain way that you should setup your PS (which escapes me at the moment) but do some searching in the chip amp forum and you will find it.

Have a good one,

Wayne-o

guycom · 6th February 2008, 08:59 PM

Thank you, I will check the led and board. Yes the xfmr has three secondary wires . Regards
Guycom

john blackburn · 6th February 2008, 10:34 PM

Also theres a flat section on the body of the led which indicates the negative leg.
It comes in handy if using second hand leds or ones that have had the legs cut previously.

danielwritesbac · 7th February 2008, 01:03 AM

Just a sec to verify. .. so the transformer has 2 wires on one end for input and 3 wires on the other end for output--a normal center tap transformer?

If so, check out the photo at this post:
http://www.diyaudio.com/forums/showt...11#post1415611

On a center tap transformer's power supply, each amplifier has only one ground wire from power supply to amplifier. That terminal is marked "CG" on your amplifier boards.

You can do a stereo layout (powers both amplifiers) nicely, if you make all the wires exactly the same length for both amplifiers.

I think the rest is on that post.

guycom · 15th September 2008, 10:02 AM

Hi, Thank you for your help. The long leg of the LED will go in the led marked hole in the board that is square with a arrow next to it. I powered up the board and that is the one that shows pos polarity.
Thanks again for the pictures and info
Guy

6th February 2008, 08:33 PM	#1
guycom diyAudio Member Join Date: Nov 2006	Brian GT chip amp build Questions Hi, I am building my first amplifier and had two questions. How do I know if the led is positioned correctly? Second I have a large iron core transforme with three secondery wire-- ca I shre the cener tap with both boards. Thank You for your help, Guycom

6th February 2008, 08:51 PM	#2
wboyd diyAudio Member Join Date: Aug 2004 Location: Louisville, KY	I believe that long tail of the LED is the pos terminal....don't shoot me if I am wrong....but it is listed somewhere in the manual. I think that there is a marking on the PS board showing where the long tail is supposed to go. As for your transformer situation...I have a question for you. Are you saying the the transformer has 3 secondary widings (6 wires), or it has 3 wires coming out of it (ie 2 colored wires and common). If the second situation is the case then there is a certain way that you should setup your PS (which escapes me at the moment) but do some searching in the chip amp forum and you will find it. Have a good one, Wayne-o __________________ "I am always doing that which I cannot do, in order that I may learn how to do it"

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
Attempting a Chip Amp Build - Need a PCB!	deadparrot	Chip Amps	7	2nd July 2009 03:14 PM
Audio Sector vs. Brian Bell chip amp	chuck55	Chip Amps	7	5th May 2009 08:49 AM
Brian gt chip amp power supply?	guycom	Chip Amps	4	29th September 2008 09:57 PM
A few chip amp questions	bigwill	Chip Amps	12	13th July 2005 10:30 AM
Questions on Brian's PCB PS (rev3.0) ??	methar	Chip Amps	0	23rd May 2005 07:41 AM

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

6th February 2008, 08:59 PM	#3
guycom diyAudio Member Join Date: Nov 2006	Thank you, I will check the led and board. Yes the xfmr has three secondary wires . Regards Guycom

6th February 2008, 10:34 PM	#4
john blackburn diyAudio Member Join Date: Sep 2006 Location: Wirral UK	Also theres a flat section on the body of the led which indicates the negative leg. It comes in handy if using second hand leds or ones that have had the legs cut previously.

7th February 2008, 01:03 AM	#5
danielwritesbac diyAudio Member Join Date: Nov 2007	Just a sec to verify. .. so the transformer has 2 wires on one end for input and 3 wires on the other end for output--a normal center tap transformer? If so, check out the photo at this post: http://www.diyaudio.com/forums/showt...11#post1415611 On a center tap transformer's power supply, each amplifier has only one ground wire from power supply to amplifier. That terminal is marked "CG" on your amplifier boards. You can do a stereo layout (powers both amplifiers) nicely, if you make all the wires exactly the same length for both amplifiers. I think the rest is on that post.

15th September 2008, 10:02 AM	#6
guycom diyAudio Member Join Date: Nov 2006	Hi, Thank you for your help. The long leg of the LED will go in the led marked hole in the board that is square with a arrow next to it. I powered up the board and that is the one that shows pos polarity. Thanks again for the pictures and info Guy