blasteriz' LM3886 PCB

blasteriz · 20th November 2004, 09:34 AM

Hello, I have traced this PCB for LM3886. I would like to hear your, expert's, opinion before building it

Is there anything wrong?
Thank you.

Upupa Epops · 20th November 2004, 10:04 AM

Yes, it is. Two things. Output choke is too big. Input ground MUST be connected to the geometrical middle of ground between PS elyts. If is not, amp will be huming.

peranders · 20th November 2004, 10:11 AM

Suitable inductor is 15 turns, diam 8-10 mm, 1.3-1.5 mm wire. My inductor has 8 mm diam, 1.5 mm wire which gives me 0.7 uH

http://home5.swipnet.se/~w-50674/hif...r0_topview.jpg

blasteriz · 20th November 2004, 01:35 PM

Oh my god, I've placed wrong link

Sorry.
Correct link

peranders · 20th November 2004, 01:49 PM

blasteriz, I split thread because it was a case of "thread napping". Please try to stick to the topic. If it's a pcb review it's better to start a new thread if you also want a review.

blasteriz · 22nd November 2004, 09:35 AM

Well, even if it is not nery good, I just started to build that MAP

We'll see how it will work

blasteriz · 3rd December 2004, 09:47 AM

Hello,
I just finished a litle army of LM3886T.
Here jou can find some fotos.

blasteriz · 3rd December 2004, 07:08 PM

Hello again,
Finally I have tested one of these boards.. Sounds nice,
But there is one problem. When output signal reaches about 25 volts, it starts tu hum in ~1MHz 1-5V amplitude. Why it occures?

demogorgon · 5th December 2004, 12:11 AM

Very nice collection of "gainclones" there!

i tried to think og what the problem could be caused by, but came short though, sorry.

marius

blasteriz · 6th December 2004, 08:08 PM

Hi,
I have drawed a graph of that hum. (sorry for my english

)

I use 4 ohm load.. This graph has a litle similarity to spike protection, but I don't think this is spike..

Any ideas are welcome

20th November 2004, 09:34 AM	#1
blasteriz diyAudio Member Join Date: Oct 2004 Location: Vilnius	Hello, I have traced this PCB for LM3886. I would like to hear your, expert's, opinion before building it Is there anything wrong? Thank you. __________________ My electronics homepage (Only in Lithuanian language now, sorry ;-)

20th November 2004, 10:11 AM	#3
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	Suitable inductor is 15 turns, diam 8-10 mm, 1.3-1.5 mm wire. My inductor has 8 mm diam, 1.5 mm wire which gives me 0.7 uH http://home5.swipnet.se/~w-50674/hif...r0_topview.jpg __________________ /Per-Anders (my first name) or P-A as my friends call me

20th November 2004, 01:35 PM	#4
blasteriz diyAudio Member Join Date: Oct 2004 Location: Vilnius	Oh my god, I've placed wrong link Sorry. Correct link __________________ My electronics homepage (Only in Lithuanian language now, sorry ;-)

20th November 2004, 01:49 PM	#5
peranders Electrons are yellow and more is better! diyAudio Member Join Date: Apr 2002 Location: Göteborg, Sweden Blog Entries: 4	blasteriz, I split thread because it was a case of "thread napping". Please try to stick to the topic. If it's a pcb review it's better to start a new thread if you also want a review. __________________ /Per-Anders (my first name) or P-A as my friends call me

22nd November 2004, 09:35 AM	#6
blasteriz diyAudio Member Join Date: Oct 2004 Location: Vilnius	Well, even if it is not nery good, I just started to build that MAP We'll see how it will work __________________ My electronics homepage (Only in Lithuanian language now, sorry ;-)


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20th November 2004, 10:04 AM	#2
Upupa Epops diyAudio Member Join Date: Aug 2003 Location: Prague,Czech Republic	Yes, it is. Two things. Output choke is too big. Input ground MUST be connected to the geometrical middle of ground between PS elyts. If is not, amp will be huming.

3rd December 2004, 09:47 AM	#7
blasteriz diyAudio Member Join Date: Oct 2004 Location: Vilnius	Hello, I just finished a litle army of LM3886T. Here jou can find some fotos. __________________ My electronics homepage (Only in Lithuanian language now, sorry ;-)

3rd December 2004, 07:08 PM	#8
blasteriz diyAudio Member Join Date: Oct 2004 Location: Vilnius	Hello again, Finally I have tested one of these boards.. Sounds nice, But there is one problem. When output signal reaches about 25 volts, it starts tu hum in ~1MHz 1-5V amplitude. Why it occures? __________________ My electronics homepage (Only in Lithuanian language now, sorry ;-)

5th December 2004, 12:11 AM	#9
demogorgon diyAudio Member Join Date: Jul 2004 Location: Behind you.	Very nice collection of "gainclones" there! i tried to think og what the problem could be caused by, but came short though, sorry. marius

6th December 2004, 08:08 PM	#10
blasteriz diyAudio Member Join Date: Oct 2004 Location: Vilnius	Hi, I have drawed a graph of that hum. (sorry for my english ) I use 4 ohm load.. This graph has a litle similarity to spike protection, but I don't think this is spike.. Any ideas are welcome __________________ My electronics homepage (Only in Lithuanian language now, sorry ;-)

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