Amp mod - bridging the unbridgeable
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Topic: Amp mod - bridging the unbridgeable
Posted By: Majestic
Subject: Amp mod - bridging the unbridgeable
Date Posted: 09 February 2012 at 10:04pm
| Is it possible to bridge amps that do not have a switch and bridge outputs? |
Replies:
Posted By: GAZ.
Date Posted: 09 February 2012 at 11:38pm
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As far as I know, bridging 2 channels of an amplifier that is not designed to be bridged = Bang! ------------- 100% Earth Moving Bass |
Posted By: lgosdset
Date Posted: 09 February 2012 at 11:39pm
| two red binding posts. |
Posted By: 4642a
Date Posted: 09 February 2012 at 11:40pm
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depends on the amp....
some amps have internal jumpers that are used to bridge the amp,
but w/o the service manual or other literature, you would not know this...
various HK Citation 16 amplifier variants were designed this way, with the internal jumpers and no
indication on the chassis or interior that the unit is bridgable....
so, what amp are you using?
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Posted By: Majestic
Date Posted: 09 February 2012 at 11:53pm
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i just bought these http://forum.speakerplans.com/clearout-prices-reduced_topic62167_page1.html" rel="nofollow - http://forum.speakerplans.com/clearout-prices-reduced_topic62167_page1.html
is it possible? thanks
|
Posted By: djeddie
Date Posted: 09 February 2012 at 11:57pm
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Yes they can, as long as you do it properly. ------------- Chas n Dave : it's like Drum and Bass but with beards. E=mc² ±3dB |
Posted By: VentureSound
Date Posted: 10 February 2012 at 1:37am
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Just doing the two red binding posts alone won't work. First, you have to invert the polarity of one of the input channels. This is not as simple as swapping signal and ground because there will be no audio (these amps only have unbalanced inputs). You need an op-amp circuit to invert the polarity of the signal, and after that you can connect the speaker between the two red terminals. In the case of the OMP amps, they will only work into 4 ohms, so after bridging you'll only be able to drive an 8 ohm load. Have a look at the link below, but if you are no good at elelctronics then some clever chap like Audiomik would probably knock you one of these up on a Sunday afternoon if you ask him nicely. http://sound.westhost.com/project14.htm" rel="nofollow - http://sound.westhost.com/project14.htm |
Posted By: audiomik
Date Posted: 10 February 2012 at 2:00am
Hmmm! don't need op-amps as there are much simpler ways - but that's a 'trade secret' Mik ------------- Warning! May contain Nuts plus springs, washers, screws, etc, etc. |
Posted By: odc04r
Date Posted: 10 February 2012 at 9:48am
| Insert signal into other side of LTP! |
Posted By: The Builder
Date Posted: 10 February 2012 at 9:58am
|
I live close enough to have bought those. I didn't because of the bridge inability.
So, if you manage it, well done, and Grrrrr  ------------- It just is. |
Posted By: cravings
Date Posted: 10 February 2012 at 10:16am
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i think i was told (i have 2 of these also) that using a balanced signal, you send the + to one channel and the - to the other channel and tie the grounds to screen... to give you the inverted ins.. i tried it, but i was really nervous and thought i smelt burning, so i kinda stopped hehe. never tried again advise you to search for previous posts on this as this has come up before with these exact amps (also search for dna900) |
Posted By: studio45
Date Posted: 10 February 2012 at 12:28pm
I've used these BK Elec based amps briefly; I managed to cock up a speaker multicore and ended up driving the output of one DNA900 into the output of another playing the next freq band, thru a driver. For several minutes at full power. The DC fuses just blew and the amps survived fine. This was after years of If you use a balanced XLR Y-Split and a phase inverting adapter, you can bridge these and it should be completely fine. Only of there is a fault with the amp will anything bad happen, and then, bad things were probably going to happen anyway! If it's really not happy the fuses will go almost instantly and if it overheats then the thermal breakers will shut it down. Bridge away! ------------- Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA |
cravings wrote:Posted By: Biggus
Date Posted: 10 February 2012 at 12:55pm
| I emailed BK Elec a while back and asked if I could bridge a MXFamp and there said yes but only if you do something with polarity of one of the input channels and some other jiggery pokery you can bridge them. I didn't fancy doing this so sold the amp in the end and got something designed for the job. Let us know if your sucessful as would be good to know if it works. good old workhorses these. |
Posted By: Earplug
Date Posted: 10 February 2012 at 1:50pm
|
It sounds like it´s ok with these, but be carefull. I had a couple of Harrison mosfet amps (X1600?) that were already bridged internally so no. I´ve also seen some Profsound amps made in the same way. More importantly, I´m pretty sure some of the Powersoft Digam amps use that trick, as well as the T-Amp D2800, D3400, etc, so maybe there´s a good reason some amps don´t have a bridge mode. ------------- Earplugs Are For Wimps! |