parallel Class AB amp?

h3ad · 19th November 2007, 03:05 AM

i was wondering if it is possible to parallel a Class AB amp??

thnx haydn

davidallancole · 19th November 2007, 03:50 AM

Yes, but you will need load sharing resistors in series with the load from each amp and you would want the output of each amp to be the same voltage.

h3ad · 19th November 2007, 10:33 AM

yeah thats what i thaught... so say if i have 2 identicle amps with the same signal, level and so on all i need is a .5R???
i have seen it done with Gainclones such as the LM3886 but i just wasnt sure if it was safe to do with a standard "solid state" amplifer...
so it is the the same principol as a gainclone then??

thnx haydn

K-amps · 19th November 2007, 01:51 PM

Parallel the inputs. Trim the DC offset to negligible levels and cross your fingers :-)

Needless to say, test it with current limiting, gradually increasing PSU current. (lamp at AC mains is one way to limit current).

peranders · 19th November 2007, 02:04 PM

Quote:

Originally posted by h3ad
yeah thats what i thaught... so say if i have 2 identicle amps with the same signal, level and so on all i need is a .5R???
i have seen it done with Gainclones such as the LM3886 but i just wasnt sure if it was safe to do with a standard "solid state" amplifer...
so it is the the same principol as a gainclone then??

thnx haydn

The gain must also be as equal as possible.

Let me ask you: Do you plan to do this, and why?

h3ad · 20th November 2007, 12:54 AM

i would like to help a friend run a single coil sub off a 4ch amplifier

my idea was parallel ch1+3 and ch2+4 then bridge them

thanx haydn

K-amps · 20th November 2007, 03:39 AM

You get points for trying to wring out every pea out of the amp, however extensive testing is required. Strapping channels is tricky, doing 4 is exponentially trickier.

h3ad · 20th November 2007, 04:20 AM

i have tested the channels and they all have a DC offset within 1mv of each other if that is any help

regards haydn

jcx · 20th November 2007, 04:48 AM

probably not safe without connecting inputs "inside" the likely DC blocking Caps - then the DC offset has to be revisited

K-amps · 20th November 2007, 01:05 PM

Yes, strap whatever is feasible, 1 mV is not bad... what are the rails of this amp? I'd use a minimum of 0.68R strapping resistors. Also is there an internal bridging switch that you will use or just feed one channel the inverted signal? Using an internal switch needs to be looked at for any issues with your proposed strapping topology.

19th November 2007, 03:05 AM	#1
h3ad diyAudio Member Join Date: Sep 2007	parallel Class AB amp? i was wondering if it is possible to parallel a Class AB amp?? thnx haydn

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
1500W RMS Class D PCB - which Class D Driver Chip is it ?	mosfetsound	Class D	11	1st April 2011 11:17 AM
How about a round-up of Class A kit power amps, or collectable vintage class A?	Brisso57	Solid State	4	14th February 2007 10:30 AM
Parallel amps & Parallel Voice coils?	officeboy	Multi-Way	7	26th May 2004 07:12 PM
pi filter in class a amp: okay to parallel inductors?	jwb	Solid State	6	20th October 2002 07:56 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

19th November 2007, 03:50 AM	#2
davidallancole diyAudio Member Join Date: Nov 2005	Yes, but you will need load sharing resistors in series with the load from each amp and you would want the output of each amp to be the same voltage.

19th November 2007, 10:33 AM	#3
h3ad diyAudio Member Join Date: Sep 2007	yeah thats what i thaught... so say if i have 2 identicle amps with the same signal, level and so on all i need is a .5R??? i have seen it done with Gainclones such as the LM3886 but i just wasnt sure if it was safe to do with a standard "solid state" amplifer... so it is the the same principol as a gainclone then?? thnx haydn

19th November 2007, 01:51 PM	#4
K-amps diyAudio Member Join Date: Nov 2003 Location: Indiana	Parallel the inputs. Trim the DC offset to negligible levels and cross your fingers :-) Needless to say, test it with current limiting, gradually increasing PSU current. (lamp at AC mains is one way to limit current).

20th November 2007, 12:54 AM	#6
h3ad diyAudio Member Join Date: Sep 2007	i would like to help a friend run a single coil sub off a 4ch amplifier my idea was parallel ch1+3 and ch2+4 then bridge them thanx haydn

20th November 2007, 03:39 AM	#7
K-amps diyAudio Member Join Date: Nov 2003 Location: Indiana	You get points for trying to wring out every pea out of the amp, however extensive testing is required. Strapping channels is tricky, doing 4 is exponentially trickier.

20th November 2007, 04:20 AM	#8
h3ad diyAudio Member Join Date: Sep 2007	i have tested the channels and they all have a DC offset within 1mv of each other if that is any help regards haydn

20th November 2007, 04:48 AM	#9
jcx diyAudio Member Join Date: Feb 2003 Location: ..	probably not safe without connecting inputs "inside" the likely DC blocking Caps - then the DC offset has to be revisited

20th November 2007, 01:05 PM	#10
K-amps diyAudio Member Join Date: Nov 2003 Location: Indiana	Yes, strap whatever is feasible, 1 mV is not bad... what are the rails of this amp? I'd use a minimum of 0.68R strapping resistors. Also is there an internal bridging switch that you will use or just feed one channel the inverted signal? Using an internal switch needs to be looked at for any issues with your proposed strapping topology.

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