wiring 4ohm DVC sub to 2channel amp

I got a MTX Thunder 275X amp for free so I was hoping to use it to power an audiobahn 8" DVC (4ohm each, 150watt each) sub. This is a typical 2 channel x 4ohm amp... the "specs" are:

37.5 Watts x 2 into a 4 Ohm load with less than 0.05% Thd+N
75 Watts x 2 into a 2 Ohm load with less than 0.1% Thd+N
150 Watts bridged into a 4 Ohm load with less than 0.1% Thd+N

but the spec sheet says it is doing 65watt x 2 into 4 ohm

I see three choices:

1) wire the 2 4ohm VCs to the 2 channels seperately. I'd get probably ~100 watts to drive the sub, about 1/3 the power capacity of the sub

2) wire the VCs in parallel (2ohm), and hook it to ONE channel on the amp (not-bridge, so the second channel is empty). I'd get ~75watts.

3) wire the VCs in parallel (2ohm), but hook it up to the amplifier in bridged mode. I get all the power of the amp, ~150 watts RMS.

I know the amp will fry if it is driven hard at 2ohms bridged, but can I realistically do this if I keep the sub-volume down? would it be safer to run the two VCs separately to the two channels?

The sub is in a sealed enclosure that is within audiobahn's recommeded volume range.

I also have an Alpine 3527S that is currently hooked up to a set of Infinity components. I'm running the amp in 2channel mode, so the specs says it is putting out ~75watts per channel at 4ohms. I could hook up the 2 channels of the alpine to get 75x2=150watts for the sub which is more than the MTX at 37.5x2=75watts.

My main question is, is it OKAY to hook up the two voice coils to separate channels on the same amp? I read somewhere awhile back that this isn't a good idea and a DVC sub should be ran by a single channel.

The alpine amp has the option to combine two inputs (say front and rear) for the output.... I could do this and then my 2-channel bridged output would be essentially mono right?

you CAN run each voice coil off of a separate channel but just make sure that the signal being input into the amplifier is a mono signal (i.e. left channel and right channel are identical).  Also, although most 2-channel amps have a single gain control for both the left and right channels, there are a few out there that have separate ones.  For those it is basically impossible to get them set up to be identical unless you use an oscilloscope to match up the gains.

basically each voice coil should receive not only the same sound/signal, but at the same volume as well.

The problem with using a 4-channel amplifier to do this is that even if you bridge the 2 front channels to power one voice coil, and the 2 rear channels to power the other channel, pretty much all 4-channel amps have separate gain controls for the front and rear outputs.  So although you can change the input so that both sets receive the same signal, you still have to worry about matching up the gains exactly.

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Ethan
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"Patience, persistence, and perspiration make an unbeatable combination for success"
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The mtx has separate gain controls for the left and right channels so that will be a problem. Is there an issue with just powering ONE of the voice coils of the sub? I could hook the mtx in bridged mode up to one voice coil and get 150 watts... probably more than enough for the 8".

You always want both coils hooked up. Running a DVC with only 1 coil being powered will result in very poor performance, as well as possible damage to the sub. You can read a little more on it here.

Here's a link on the dangers of Independant Wiring as well.

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
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Yea well since your amp has separate gains for the left and right channels I would recommend not hooking up a voice coil to a separate channel.

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Ethan
-----
"Patience, persistence, and perspiration make an unbeatable combination for success"
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Ok thanks for the info. I clearly understand the problems with hooking up only one coil. I've given up on using the two amps I have to power the 8", mostly because I just managed to pick up a bat-wing style RF 360a2 for $25. I'm going to run the amp in bridged mode and just run the sub in series (8ohm)... I'll get half the rated power but that should still be plenty (min rated power would be 180watts, but I understand many of these amps produce nearly double so I'm sure the 8" will be feed properly).

brad

I wouldn't say nearly double, but RF amps are widely known for producing more power then they are rated at. I asked them about it once, and their reply was the rated specs were the "absolute minimum" power that would be produced. So you may see double, you may only see 10 extra watts. Either way, you'll get more then you pay for with RF (unfortunately you tend to pay a little more just for the name though).

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Squirrel
"No more Cpt. Kirk chit chat"
If its too loud, then you're too old
Donate to the12volt.com