Here are the specs for the Thunder 6500D amp...

Specifications
Power 12.5 VDC
2 Ohm Load 500 w x 1
4 Ohm Load 250 w x 1

Power 14.4 VDC
2 Ohm Load 775 w x 1
4 Ohm Load 450 w x 1

Does 14.4VDC indicate a "peak" power output or can I get a steady 775W out of it at 2 ohms? If so, how do I wire it at 14.4V?

 

The output power is entirely dependent on the voltage of your vehicle's charging system.

Normally most alternators have a built-in or separately mounted voltage regulator that keeps the vehicle system voltage at 14volts or just above.

Provided your alternator is big enough (amperes output) and you are running good 4 gauge cables (both power & ground) and your headlights don't do the disco-dance when you crank it then we can assume that for the most part your amplifier will be receiving around 14 volts.

When your motor is not running and you're cranking the tunes in the parking lot then your amp will of course receive 12 volts or less and quickly drop in voltage after listening for several minutes or really loud. Extra batteries help for listening time while parked but not while driving.

A stiffening capacitor (1 farad) helps to stabilize the voltage at the amplifier power terminals. However, if your alternator isn't up to the task then even with a stiffening cap your overall system voltage will slowly drop. The cap only smooths out the power spike drops that bass hits create.

14.4 volt measurements are really under "ideal" conditions.

On the other hand I have heard that the Fosgate amps come with a "birth sheet" and most are officially underrated and the one you buy will typically put out slightly more than rated.

Looking at the specs one can assume the power supply of the fosgate is unregulated. All this means is that it turns battery power to higher voltage for the transistor rails at a fixed ratio. So if your battery voltage goes down, so does your rail voltage, and consequently your maximum power. The advantage is if you run high battery voltage it will put out more power.

Amps with regulated power supplies will produce constant output power independent of battery voltage. They usually increase the pulse width of the power supply to generate more current and keep the rail voltage constant. Some can work down to 9 volts but not all. They will draw significantly more current when undervoltage. As you may know Power (watts) = Volts X Amperes. To make the same power at a lower voltage you need to increase the amperes.

 

Just kidding. I don't know about all that technical stuff but I'm running 2 MTX amps and both of them are running at more than advertised power. If you buy one, it comes with a test sheet that gives you the power output of your individual amp. Both of mine are putting out more than advertised power. I'm more than happy with both of them. Hope this helps.

Bob

 

LOL. Ya... my head hurts too.

Hey rtroha, you have to have one of the best lookin 4x4 F150's around. It's a good combination.

With amplifiers it's more about matching it to the intended load impedance. If you're running a lot of subs in parallel for less than 4ohms then get class-d, otherwise an amp that bridges into 4 ohms for max power.

MTX is fine. It's not really a brand issue as much as getting the right amp for your particular setup/situation.

Looking at the Ultimate 1200D it looks to be the bargain of the month/year in terms of power output per $. Anything else even close is $150-200 more. I don't have any experience personally... just looking at the specs.

 

Thanks for the replies, that helped a lot actually. I read up on the JBL BP600.1 and decided to use it instead. My two subs are 400w rms a piece, so they should each be getting well over 300w with the 600.1 seeing as how most amps are fairly underrated. The JBL was much cheaper and from what I've heard from other people, there's only a slight drop off from the MTX amp in terms of quality, if any.

 

the JBL is a great amp for the money you pay, I have heard of now problems at all. It really does put out what it is rated at, a lot of amps DON'T put out what they are rated at, and only SOME amps put out more than they are rated. Cadence is a line of amps you could look into, better features than the JBL, a little more expensive, but SOLID!! and they are slightly underrated, check out shop4sound.com a very reliable site, and one of the few that carries cadence. You can go on caraudiotalk.com and ask the guys on the forum there about cadence amps, you will find out very quickly that they are AWESOME!!

 

Actually, my MTX500D came with a birthsheet. However, I'm at work now and I can only remember that at 14.4V and 2ohms it tested 696w x 1.

I have the towing pkg with the 130w alternator and my headlights dance at high volume even with 4ga power to a distribution block and a six inch run of 8ga to the amp. Guess I need a cap and an auxillary battery to keep up.

 

Shouldn't need a cap with the auxilary battery, that would be a little redundant, the auxilary batter would be do MUCH more than a cap ever would. An auxilary battery wired to a battery isolator would do wonders I'm sure.