Is a bridge / parallel configuration of 3875 is better for my speaker ?

100db · 7th March 2006, 10:24 AM

Hello,

I'm using inverted LM 3875 with 24-0-24 v power supply ( +/- 35v to the pin).

I would like to know if I use bridge or bridge+parallel configuration can make my gain clone drive my speaker better ?

My speaker is Scan 15w-8530 + Vifa XT25, serie XO.

Bazukaz · 7th March 2006, 10:38 AM

I depends on your loadspeaker's impedance.
35V is quite much for this amp.For this voltage , a bridged config will hardly be usable for any lower loadspeaker impedances than 16Ohms.
You should search for overture design guide excel spreadsheet at www.national.com to get an idea what output powers at known impedance speakers you should expect.

Regards,
Lukas.

100db · 7th March 2006, 04:06 PM

Bridge will make the GC see a speaker as half impedance and parallel will push it back to normal impedance, am I understand correct ?

sreten · 7th March 2006, 04:33 PM

Quote:

Originally posted by 100db
Bridge will make the GC see a speaker as half impedance and parallel will push it back to normal impedance, am I understand correct ?

Correct. But how about 3 paralleled bridged pairs ?

/sreten.

100db · 8th March 2006, 02:40 AM

Quote:

Correct. But how about 3 paralleled bridged pairs ?

To make it handle a lower impedance speaker properly ?

This would be very interesting, anybody try this before ?

Khron · 8th March 2006, 10:14 AM

Yes, it's been tried before, except it's with 6 LM3886s...

http://www.shine7.com/audio/bpa300.htm

DIYdo · 8th March 2006, 10:40 AM

From my BPO experiences you don't get the power gains expected. For the extra work load I have found it easier and more practical to use discreet components. Not saying not to try though. Chips are very easy to work with, and are very reliable.

sreten · 8th March 2006, 10:42 AM

Quote:

Originally posted by Khron
Yes, it's been tried before, except it's with 6 LM3886s...
http://www.shine7.com/audio/bpa300.htm

Hmm...

Its not 3 paralleled bridged pairs, its a pair of 3 paralleled amplifiers bridged.

/sreten.

7th March 2006, 10:24 AM	#1
100db diyAudio Member Join Date: Dec 2005 Location: Bangkok, Thailand	Is a bridge / parallel configuration of 3875 is better for my speaker ? Hello, I'm using inverted LM 3875 with 24-0-24 v power supply ( +/- 35v to the pin). I would like to know if I use bridge or bridge+parallel configuration can make my gain clone drive my speaker better ? My speaker is Scan 15w-8530 + Vifa XT25, serie XO.

8th March 2006, 10:40 AM	#7
DIYdo diyAudio Member Join Date: Feb 2006 Location: Lincs	From my BPO experiences you don't get the power gains expected. For the extra work load I have found it easier and more practical to use discreet components. Not saying not to try though. Chips are very easy to work with, and are very reliable. __________________ I got my finger stuck in my ear!

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
Levinson ML-3 mono parallel configuration	BrianEno	Solid State	6	12th July 2007 07:26 AM
Bridge/Parallel Configuration Help	mothman	Chip Amps	4	9th March 2005 02:38 AM
Parallel 3875 or single 3886 for low impedance speakers?	Groucho2004	Chip Amps	2	17th July 2004 08:31 PM
Help! Parallel 2x 3875 per channel design - please advise.	loong	Chip Amps	23	3rd April 2004 10:08 PM
bridge mode for LM 3875	partyjups	Solid State	2	5th June 2001 05:49 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 March 2006, 10:38 AM	#2
Bazukaz diyAudio Member Join Date: Nov 2005 Location: Vilnius	I depends on your loadspeaker's impedance. 35V is quite much for this amp.For this voltage , a bridged config will hardly be usable for any lower loadspeaker impedances than 16Ohms. You should search for overture design guide excel spreadsheet at www.national.com to get an idea what output powers at known impedance speakers you should expect. Regards, Lukas.

7th March 2006, 04:06 PM	#3
100db diyAudio Member Join Date: Dec 2005 Location: Bangkok, Thailand	Bridge will make the GC see a speaker as half impedance and parallel will push it back to normal impedance, am I understand correct ?

8th March 2006, 10:14 AM	#6
Khron diyAudio Member Join Date: Jul 2005 Location: Finland	Yes, it's been tried before, except it's with 6 LM3886s... http://www.shine7.com/audio/bpa300.htm

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