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Discussion Starter · #1 ·
Hello,

Looking for a bit of help.

I have just installed one of the O-Audio 500w bash amplifiers into an 80ltr sealed enclosure, with an Acoustic Energy AV15-X driver.

I am using the subwoofer pre-out on a Denon AVR-1910 amp for a signal.

Testing it for the first time, and after a quick set up I was playing the bass heavy intro to Transformers 2 with the amp set to -10db and the fuse in the amp has blown.

Could this be a problem with my particular amp, or something else?

Thanks in advance for any help.
 

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other then it being a problem with the amp it could be that you have the sub wired incorrectly presenting too low of a resistance to the amp. i did a quick search on that driver but came up with nothing on what the resistance of it is so i cannot go any further then that. worth looking into.
 

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Discussion Starter · #4 · (Edited)
I know the driver is the dual 2ohms version wired in series which should give a 4ohm load, if that helps.

Just before the fuse went the sub was heard to be making a nasty clicking noise, at first I thought it could be the driver bottoming out.

Also, on a previous run through the same scene the amp made this noise but the fuse didn't blow.
 

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Discussion Starter · #5 ·
FYI - I sent an email to OAudio just before I posted this thread.

I am a bit disappointed that they have not been in touch yet, fingers crossed I'll hear from them soon.
 

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Discussion Starter · #7 · (Edited)
For anyone willing to give it a try I have uploaded the intro from my Blu Ray rip. The issue seems to occur at about 28 seconds in.

http://www.mediafire.com/?mnx1mi5gdhd

I have owned an SVS SB12+ and a BK Monolith before I went to DIY, and both of those also struggled with this particular intro (at around 28 seconds in) Perhaps there is something wrong with the rip!?

Take care!
 

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Hi Tyler,

I just received your PM, i could otherwise PM you but after i read the message "..you will be be band, when you PM more than 5times, decided to write you here.

Of course its possible whe you have 2 amps oaudio. One amp receives a normal input signal from your equipment and the other amp receives an inverted the same signal, remember it must be mono or only L or only R-signal. There should be "inv" somewhere on your preamp or X-Over, for example all X Overs have it, other kind of audio equipment too. And not to forget you connect the speaker/the subwoofer between the two outputs(no ground cable comes in consideration here, only the active ones from the both outputs) and you are done 4times more power!! Not to forget you turn off the overcurrent protection otherwise the power will be as with one amp. I did it with a friend of mine several times.. with my self designed amp too, as i understand from electronic circuitry i did the inversion of the one channel internally in the amp itself and now have the pleasure to hear much stronger sound :). Be carefull, when the load is tha same each amp is loaded thermally with twice more power as rated, but that is a musical power so it shouldnt be a problem..

All i have said that far is meaningless when there is a bridge mode available on your amps. follow then the instructions for this mode

Good luck and tell us hot it tourned out for you
 

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I'm going to issue a strong warning re using a pair of O-Audio plate amps in a bridged configuration as Veltonian has suggested.

As the load of the AV driver is 4Ω, bridging will present each amplifier with an effective 2Ω load. Having just looked at the O-Audio site, and read the user manual for this amp, I see nothing that indicates the amp is rated for 2Ω use; get the OK from the manufacturer that 2Ω is an acceptable and safe load or don't do it. Depending upon the way they have implemented the BASH, each plate amp may already be bridged (BTL) so using two plate amps bridges this way may not work or cause damage to them.

For a couple of other reasons, I'm also dubious about using a pair of plate amps bridged. Again, get the OK from O-Audio to do this first.

I just modelled the AV15X in 80L sealed with 420W and got an F3 at 48Hz. If you are adding much EQ, you will soon run out of power at fairly modest levels and this is my guess at what is happening (hard to diagnose faults at a distance). A closer look at chart 1 in the OM shows that all of the sub filter frequency settings also add boost at the bottom of their range; the 12Hz, which is what I would have chosen with a sealed sub is adding what looks like 12dB of boost at 10Hz.

My engineer's gut says you've played a section with a lot of high level sustained low LF content loud, and overloaded the amp, tripping the protection.

Try and borrow a bigger amp and see how that works.

Edit: After I typed the above and before I hit 'post' I recalled this amp had been tested elsewhere, in Chas' Amp Testing thread at AVS. Here's the link to your amp. You need more power if you want to be able to play as loud as you did in your test and not blow fuses regularly.
 

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this that the amps can be damaged when already bridged is nonsence, false.. Anyway you cannot benefit from the bridge mode if each plate amp is already bridged, of course no question about that..you would get otherwise the same ouptut as with one amp...no doubt about that... so make sure the amp is not already bridged

The only remaining thing to consider is the 4Ohms load(twice more voltage across the same load means twice more current thus 4 times more power to the sub ingoing) if the amp can provide twice more current as stated, you could ask oaudio. If so you are good to go with 4times more power
 

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this that the amps can be damaged when already bridged is nonsence, false..
I said 'may' as I looked at a few different BASH chipsets and implementations before I posted and it was intended as a caution. I do not know the details of the OA set up and I have seen amateurs make some shocking mistakes and damage gear, even when it should not have been. So, even though I know well how a BTL sytem works (I'm an EE), as a Moderator I feel it best to be extremely conservative in making recommendations to use a product in a way not (yet shown to be) approved or recommended by the manufacturer.

The only remaining thing to consider is the 2Ohms load if the amp can provide twice more current as stated, you could ask oaudio. If so you are good to go with 4times more power
As it is already not doubling down into 4Ω from 8Ω, I seriously doubt it will.
 

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Did you check your high pass filter tuning knob on the O-audio plate amp?

The lower settings actually have quite a lot of built in boost that could cause the blown fuse, especially if the material has a lot of energy at 10-20Hz. It is misleading, the 12 Hz HPF actually has 10dB boost at 10Hz!! The graphs are on page 12 of the manual.

I couldn't post a link because i'm a new user, but it is easily found on the website.
 
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