Chipamp.com pcb with linkwitz 3875 design

akunec · 7th June 2005, 05:39 AM

I'm building a gainclone for tweeters and mids using the design shown here: http://www.linkwitzlab.com/images/graphics/3886amp.gif . For Ci, I'm gonna use a 4.7uf cap, but im having difficulty installing it on this chip: http://www.chipamp.com/lm3875.shtml. The problem is that signal ground is connected to both the 20kohm input to ground and the 1k resistor right above Ci. If I put the cap on the signal ground, the cap would be in series with the 1k resistor AND the 20kohm input to ground resistor, which the design does not call for.

How do i solve this problem?

Thanks
Alex

motherone · 7th June 2005, 08:02 AM

Why don't you insert one pin of the cap into the ground side of Ri pad, and insert the resistor into the other side. Then solder the two pins that aren't attached to the PCB together?

akunec · 7th June 2005, 05:41 PM

The 4.7uF cap is really large. I don't think there would be enough room to do that.

motherone · 7th June 2005, 07:06 PM

Well, you could try using a 50v/4.7uF blackgate-N. They're pretty small. They're available inexpensively over at http://www.kyoto-electro.com or any number of other parts suppliers (parts connexion, etc.)

On the plus side, they're usually a heck of a lot cheaper than an "audiophile" metallized Poly or film & foil cap.

7th June 2005, 05:39 AM	#1
akunec diyAudio Member Join Date: Aug 2004 Location: Alberta	Chipamp.com pcb with linkwitz 3875 design I'm building a gainclone for tweeters and mids using the design shown here: http://www.linkwitzlab.com/images/graphics/3886amp.gif . For Ci, I'm gonna use a 4.7uf cap, but im having difficulty installing it on this chip: http://www.chipamp.com/lm3875.shtml. The problem is that signal ground is connected to both the 20kohm input to ground and the 1k resistor right above Ci. If I put the cap on the signal ground, the cap would be in series with the 1k resistor AND the 20kohm input to ground resistor, which the design does not call for. How do i solve this problem? Thanks Alex

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
Grounding chipamp 3875	marcus7601	Chip Amps	10	10th April 2009 10:33 PM
FS chipamp 3386, 3875, 1 enclosure	wendell	Swap Meet	4	15th June 2008 03:06 PM
Preventing a 3875 chipamp from blowing tweeters	bcdzt5	Chip Amps	8	6th February 2008 07:23 PM
Recommended UK transformer for 3875 chipamp?	Colin	Chip Amps	6	1st March 2007 08:02 PM
Help! Parallel 2x 3875 per channel design - please advise.	loong	Chip Amps	23	3rd April 2004 10:08 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

7th June 2005, 08:02 AM	#2
motherone diyAudio Member Join Date: Apr 2003 Location: Seattle	Why don't you insert one pin of the cap into the ground side of Ri pad, and insert the resistor into the other side. Then solder the two pins that aren't attached to the PCB together?

7th June 2005, 05:41 PM	#3
akunec diyAudio Member Join Date: Aug 2004 Location: Alberta	The 4.7uF cap is really large. I don't think there would be enough room to do that.

7th June 2005, 07:06 PM	#4
motherone diyAudio Member Join Date: Apr 2003 Location: Seattle	Well, you could try using a 50v/4.7uF blackgate-N. They're pretty small. They're available inexpensively over at http://www.kyoto-electro.com or any number of other parts suppliers (parts connexion, etc.) On the plus side, they're usually a heck of a lot cheaper than an "audiophile" metallized Poly or film & foil cap.

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