View Full Version : Anyone with experience paralleling Amp9 outputs?
markroussey
15-Apr-08, 22:25
In picking up where the bridging thread left off, has anyone actually tried paralleling two or more input/output combinations on an Amp9 to increase the current (amperage) capacity for low impedence loads?
If so, were there any issues - oscillation, DC offset, current loops, overheating...anything? Thanks in advance for any shared experiences.
I did a few times, there was only one time an issue because I used inferior plugs, the amp went into protection. But it wasn't broken, after the connections were made proper the amp worked fine again....
It's easy to do, there are no mods necessary, just connect the input wires of the desired channels together and than connect the output channels together the same way... (+to+ and -to-).
It did have an effect on the sound. For my ESLs it wasn't so pretty, but for dynamic speakers it seemed to add a lot more control. Plus the bonus of being able to drive insane loads....
No overheating problems either, no difference....
------X-max. can be several meters on any driver, too bad it can be done only once...------
I have a dream of a dual 2ohm voice coil subwoofer running off an amp9b with either 2 or 4 paralleled outputs. :)
That's a very good idea, especially the bass benefits from the extra control....
------X-max. can be several meters on any driver, too bad it can be done only once...------
markroussey
16-Apr-08, 18:33
Great! Thanks for the feedback! I've already blown one Amp 9, so I'm trying to be more careful with this one.
quote:Originally posted by y8s
[br]I have a dream of a dual 2ohm voice coil subwoofer running off an amp9b with either 2 or 4 paralleled outputs. :)
When paralleled you can even connect two of those....
------X-max. can be several meters on any driver, too bad it can be done only once...------
quote:Originally posted by V-bro
[br]
quote:Originally posted by y8s
[br]I have a dream of a dual 2ohm voice coil subwoofer running off an amp9b with either 2 or 4 paralleled outputs. :)
When paralleled you can even connect two of those....
With a 24VDC supply? I thought it was only rated 4x100W at 4ohm max. If I use the dual voice coils, that's two 2 ohm loads or one 1 ohm load.
or maybe I could run eight 8 ohm woofers in parallel!! [:o)]
If it's growing too heavy the overcurrent protection will trip.
No indeed it is 4x100 at 4 ohms, but 2x200 parallelled it's 2 ohms stable and 1x400 it's 1 ohm stable....
Do keep in mind that for the extra gain you need the lower impendace, otherwise it'll stay the same gain (at the same load). The extra power is only current, not voltage....
------X-max. can be several meters on any driver, too bad it can be done only once...------
markroussey
19-Apr-08, 21:11
Actually, I think it was Jan that pointed out that the real limit is the amount of peak current you push - 10A/channel - that trips the overcurrent protection. I actually was able to get 11A rms for a 2 minute period of time; that, of course, was the last time....
Nonetheless, I would say that you're safe pushing a 2 ohm load w/24V, providing that your bass content is limited, i.e. the bass drum beat, and not rms content. With 12V, I would guess (since I can't say I've tried this) that you could get away with a 1-ohm load/channel, but parallel two to be safe. Can you say, "Subwoofer Line Array?"
It sounds like fun, but I'm not sure there's going to be much benefit using this for a Subwoofer. The enhanced imaging and spatial separation these amps are known for is lost on this type of application, since a sub is mono and non-directional in output.
On the other hand, if you're just looking for a fun project to experiment with amps and speakers, then you have come to the right place.
***If it was easy, everyone would be doing it***
quote:Originally posted by V-bro
If it's growing too heavy the overcurrent protection will trip.
No indeed it is 4x100 at 4 ohms, but 2x200 parallelled it's 2 ohms stable and 1x400 it's 1 ohm stable....
Do keep in mind that for the extra gain you need the lower impendace, otherwise it'll stay the same gain (at the same load). The extra power is only current, not voltage....
------X-max. can be several meters on any driver, too bad it can be done only once...------
I still don't get it. How exactly would you have to wire the AMP9b outputs to get it to work on (just) 2 speakers? And I suppose you also have to do something about the 4 inputs if you only have 2 (left/right)? How does one do that?
Too bad I can't find anything about this in the AMP9b nor the AMP9 info I could find in the support page of 41hz.com.
Hi, yes, Jan should have highlighted this option a bit better (including info about the technical differences) on these pages...
Basically for paralleling the input is connected + to + and - to -. And do the same with the outputs of these channels.
Than you have two outputs making one, you can add another in/output or add them all together.
WHAT YOU SHOULD NOT DO!!!!!!!!!!!!
Is connecting outputs to inputs!!!!!!!!!
Probably the amp will go into protection.... but it can just as well go wrong....
------X-max. can be several meters on any driver, too bad it can be done only once...------
Even more foolproof would be to say:
Paralleling means you take one input wire and connect them to 2 or more of the input channels, + to +, ground is shared so don't split the gnd or you may get groundloop. Note the input channels you connecting together and those output channels is connected to eachother + to +, - to -. It's very important to note that - is not ground on the outputs.
I am planning to power my subwoofer with this amp in my car.
http://img253.imageshack.us/img253/2112/260hdsrr9.jpg.
This is a single coil subwoofer. My in dash deck is an alpine 9886r with 2x pre out (front + rear) and one subwoofer out.
I use another AMP9 for front + rear and i'm adding this to the subwoofer out (wich is made of two rca L+R).
How do i have to connect my amp9 to work in mono?
Will this configuration work?
http://img231.imageshack.us/img231/1874/monoiv5.th.jpg.
How do i have to connect the inputs?
Thank all you for any help
Fabio
That'll work, you basically need to do the same with the inputs, but the ground is already combined to one on the PCB....
So just solder a wire over the four holes that are nearest to the four blue caps....that'll be your hot input, ground just has to be one of the holes nearest to the edge of the PCB...
Only problem is that you can't get L+R unless you use some kind of way to mix both. I think it can be done by connecting them together after placing two caps (similar to the blue ones) in series with the hot L and R wire.
For subwoofer usage I think it won't hurt the soundquality too much having the signal go through two caps, otherwise it may be possible by modding the PCB to connect the L and R together after the blue caps on the PCB. Only I'm not so sure if the chip inputs can be directly paralleled without problems...but I do think they can.... And of course in that case the L and R signal will have to be connected to the PCB two holes per channel...than forming one after the caps....
------X-max. can be several meters on any driver, too bad it can be done only once...------
Still it's probably much better to get yourself another one of those sub drivers, or even better a 2x2 ohm dual voice coil woofer....
------X-max. can be several meters on any driver, too bad it can be done only once...------
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.