Can anybody check this LM3886 PCB

generator***** · 3rd March 2010, 02:11 PM

Hello friends. This is my first pcb design. can you check this pcb.

Redshift187 · 3rd March 2010, 03:54 PM

A schematic would be helpful.

kuldeepsingh · 3rd March 2010, 03:59 PM

nice attempt. good grounding layout and separation of input and output. Have you made power supply PCB?

ratza · 3rd March 2010, 04:16 PM

Pretty nice. Move the 100nF decoupling caps closer to the LM pins. Why do people use input capacitors that big? Use smaller ones. You won't believe it, but the quality of the capacitors on the negative feedback influence the sound quality as well.

generator***** · 3rd March 2010, 09:00 PM

I used the schematic in LM4780 datasheet (Auxiliary Amplifier Application Circuit).
I have WIMA 1uF/400V caps therefore the input capacitor is so big =).
thanks for your comments and advices

tomchr · 3rd March 2010, 10:03 PM

You probably don't want your supply caps overlapping with the supply connector/terminal block. Also, I suggest leaving more room (50-100 mils) between the input connector and the large cap. Furthermore, your 2200uF caps are probably rather tall, thus, they will interfere with the mounting of the LM3886. If you have the parts already, I suggest placing the parts on a print-out of the layout and verifying that you can get to the mounting screw of the LM3886 with a screwdriver with the supply caps in place. And as others have said already, the 100 nF decoupling caps should be right at the pins of the LM3886 for them to be the most effective.

Otherwise, it looks pretty good -- assuming the layout matches the schematic that is.

~Tom

Roushon · 4th March 2010, 11:20 AM

I think the negative track behind the LM3886 should be avoided as
you will not be able to fit the heat sink so that some part of it
goes below the IC (that is below the PCB). I mean the PCB should end just
before the back of LM3886. Also as already mentioned, decoupling caps
be as close to LM3886 as possible and the input (including the input cap) should
be away from the filter caps and the negative track.

I just built a big project around LM3886, so these are my first hand
experience. High power amp like LM3886 will amplify a very slight
distortion in the input to a very large audible one.

I hope my limited knowledge helps in some way or the other.

Roushon.

3rd March 2010, 03:54 PM	#2
Redshift187 diyAudio Member Join Date: Aug 2008	A schematic would be helpful. __________________ Tyler

3rd March 2010, 03:59 PM	#3
kuldeepsingh diyAudio Member Join Date: Aug 2006 Location: Chennai, India	nice attempt. good grounding layout and separation of input and output. Have you made power supply PCB? __________________ . . .. ... ..... ........ ............. ..................... .................................. My Best LM3886 PCB layout

3rd March 2010, 04:16 PM	#4
ratza diyAudio Member Join Date: Dec 2007 Location: Sibiu, Romania	Pretty nice. Move the 100nF decoupling caps closer to the LM pins. Why do people use input capacitors that big? Use smaller ones. You won't believe it, but the quality of the capacitors on the negative feedback influence the sound quality as well. __________________ Any solution is a compromise.

4th March 2010, 11:20 AM	#7
Roushon diyAudio Member Join Date: Sep 2004 Location: Mumbai (Bombay)	I think the negative track behind the LM3886 should be avoided as you will not be able to fit the heat sink so that some part of it goes below the IC (that is below the PCB). I mean the PCB should end just before the back of LM3886. Also as already mentioned, decoupling caps be as close to LM3886 as possible and the input (including the input cap) should be away from the filter caps and the negative track. I just built a big project around LM3886, so these are my first hand experience. High power amp like LM3886 will amplify a very slight distortion in the input to a very large audible one. I hope my limited knowledge helps in some way or the other. Roushon. __________________ S. Roushon

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


	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

3rd March 2010, 09:00 PM	#5
generator***** diyAudio Member Join Date: Mar 2009	I used the schematic in LM4780 datasheet (Auxiliary Amplifier Application Circuit). I have WIMA 1uF/400V caps therefore the input capacitor is so big =). thanks for your comments and advices

3rd March 2010, 10:03 PM	#6
tomchr diyAudio Member Join Date: Feb 2009 Location: Greater Seattle Area	You probably don't want your supply caps overlapping with the supply connector/terminal block. Also, I suggest leaving more room (50-100 mils) between the input connector and the large cap. Furthermore, your 2200uF caps are probably rather tall, thus, they will interfere with the mounting of the LM3886. If you have the parts already, I suggest placing the parts on a print-out of the layout and verifying that you can get to the mounting screw of the LM3886 with a screwdriver with the supply caps in place. And as others have said already, the 100 nF decoupling caps should be right at the pins of the LM3886 for them to be the most effective. Otherwise, it looks pretty good -- assuming the layout matches the schematic that is. ~Tom

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

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Please Check this LM3886 Schematic	mymindinside	Chip Amps	28	21st August 2007 09:23 PM
PCB Check	Khron	Chip Amps	48	28th May 2006 09:55 PM
Please check this LM3886 layout for me	CJ900RR	Chip Amps	7	26th February 2006 08:35 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