# Amplifier review: Rockford Fosgate Power T4004



## dawgdan (Aug 10, 2006)

I can't help but review the equipment I have. 

After helping a co-worker install a pair of 12" subs into his son's car, I got re-bitten by the audio bug pretty hard. After considering many options, I decided that a 1-ohm stable, 4-channel amp was the most economical choice for the equipment I already had (dual 4 ohm sub, passive components). Being on a pretty tight budget, I scoured the classified ads on the net, trying to find something either used or in great shape for the right price. I pretty much narrowed my search down to an old Phoenix Gold Titanium 500.4 or the Rockford Fosgate Power T4004. While the PG was more compact, I came across a deal I could not refuse for the T4004 - brand new in box for under 200 bones. I jumped on it.

*Specs? What specs?*
It's no secret that RF has been underrating their amps for many years now. The T4004 is no exception. Rockford's (ridiculous) ratings for this amplifer at 14.4 volts (CEA2006 compliant):

Stereo 4 ohm: 25 x 4
Stereo 2 ohm: 50 x 4
Stereo 1 ohm: 100 x 4
Bridged 4 ohm: 100 x 2
Bridged 2 ohm: 200 x 2

So what are the real specs? My birthsheet reads 98 watts per channel at 4 ohm stereo, 152 watts per channel at 2 ohm stereo, and a whopping 757 total RMS watts at 1 ohm! This amp is no ringer - RF's own average measurements for this little monster at 4 ohm stereo is 90 watts! 

*Physical impressions*
Upon receiving the amplifier, the weight was the first thing that I noticed. At a portly 15 pounds and a fairly large 16.3" x 12.9" x 2.3" footprint, the power numbers start becoming more believable. Although this is the smallest 4-channel amplifier offered in their Power series, this amp will eat up some space in your trunk. The finish is an attractive powdercoated and scratch-resistant gunmetal gray. There's no fan cooling on the T4004, only convection-style radiant cooling. Three large, black, cast-iron, outer heatsinks with integrated mounting holes provide the dissipation. The owner's manual states that mounting the amplifier flat will result in the best cooling performance (that's how I mounted it). 

The terminals are solid, able to accept bare wire or terminal ends. The way they grip the wire with a barrier clamp provides more holding power than often-used set screws. I fed the T4004 with KnuKonceptz 4-gauge power and ground wire with an 80-amp inline mini-ANL fuse. This being RF's premium line, I would have liked to have seen screw-on RCA inputs, but the standard-type soldered inputs work very well. There is a nice trim cover that hides wiring and controls, as well as 12 db/octave Butterworth filters for the front and rear channels. The amplifier did include a fancy-looking bass remote that provides up to an 18 db increase with variable center frequency, but I do not plan on using this item.

With my amp still being under warranty, I chose not to open the cover. However, I have seen several pics of this particular amp with its cover off - including one directly on RF's website (you won't find hardly any other manufacturers showing their amps "topless"). Everything is very neatly packaged - so much so that I can't help but wonder, "Where's the Beef?!" Don't worry.. it's there.

*Real Performance*
After a few weeks of other projects going on, I finally got to install this puppy. The test setup.. the source unit is a factory non-Bose Mazda 6 CD player with the front channels spliced into a Navone N774-V line-out converter. JL Audio's Manville Smith has given data indicating that the front channels of this head unit have a relatively flat frequency response. The T4004's front channels are high-passed at 80 Hz, powering a pair of Alpine Type-X passive crossovers that feed a pair of Ascendant Audio 6.5" Poly mids and a pair of Seas Neo tweeters mounted in the A-pillar. The rear channels of the T4004 are bridged into a 2 ohm load to an Image Dynamics IDMAX in a 1.2 cubic foot sealed enclosure, low-passed at 80 Hz.

Using some 0db test tones and my trusty ears to properly set the gains, I powered up the T4004 to some Alice in Chains Unplugged. The impact was immediately there.. turn that bass down! With the IDMAX receiving a guesstimated 350 watts, the T4004 was doing just fine feeding it. The highs were crisp, mids were detailed. I took the car out for a drive in pouring down rain, jamming out to several different CD's - Faith No More, Rush, Mike Jones. The T4004 was not breaking a sweat. It did get a little warm to the touch, but that's to be expected on an amp that does not have a cooling fan.

Overall, I'm very satisfied with the purchase. I feel like RF has kinda gotten a bad rep in the past few years, ever since they started showing up at Best Buy and the like. I'm here to say that the Power series of amplifiers still uphold the bulletproof Rockford Fosgate aura of yore. They are built in the USA and they are underrated beyond belief. I've never used brands like Audison or Zapco before, but I truly feel that the RF Power series is right up there in terms of build quality and exceeds those brands in terms of watts per dollar. Two thumbs up to Rockford Fosgate for delivering huge amounts of juice yet again.


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## Sephiroth619 (Jun 24, 2005)

dawgdan said:


> *Specs? What specs?*
> It's no secret that RF has been underrating their amps for many years now. The T4004 is no exception. Rockford's (ridiculous) ratings for this amplifer at 14.4 volts (CEA2006 compliant):
> 
> Stereo 4 ohm: 25 x 4
> ...


Wow. That's almost too good to be true.

[edit] Whoops, read that wrong. I thought you meant 94x4 watts @ 4 ohms. So you're saying the amp is overrated by a few watts.


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## dawgdan (Aug 10, 2006)

Each channel makes 98 watts at 4 ohms. It produces almost quadruple what its rating says.


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## Irondan (Jun 9, 2008)

god, i dont know what your talkin bout but it sounds sweet


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## pikers (Oct 21, 2007)

I use this very amp to drive a three-way front stage and subwoofer. Doesn't really get all that warm.

These amps get credit from me for performing, but also because they underrate themselves. Unfortunately dumb kids see "25x4" and pass it by. This is something that Rockford should pay attention to, and maybe by splitting the difference on published ratings would help their sales, but whatevs...


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## Foglght (Aug 2, 2007)

I would imagine they are doing this to possibly get back into the competition scene, as a 100x4 amp counts against you way less than a 400x4, right? Could possibly send you down a class with the 1/4 wattage rating.


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## demon2091tb (May 30, 2005)

How much are they?


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## dawgdan (Aug 10, 2006)

Keep in mind this amp is a previous model, I think manufactured from 2003 to 2006. 2007 saw the new compact Power series. This review refers to the massive tank model like this: 









I paid just shy of $200 for mine, bnib. Waaaay below retail, but I had a connection at the time (not anymore).


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## drtool (Nov 26, 2007)

If you could not go Zapco I allways liked RF for a budget amp. You can get super deals on new if you look long enough. After my Nak and other equiptment was stolen I went with RF 5000 (130.00 new) so far so good.3 months. And made in U.S.A.


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## Aaron Clinton (Oct 17, 2006)

*Nice review, I was tempted to grab one for myself, but my ZED itch got the better of me.*


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## FunkyJam (Jun 5, 2009)

Hey, sorry to drudge up the old thread. Found it on google. Do you think this baby could run a pair of Boston SX65's & a Boston G5 12" acceptably? I have a G1, I want to move to a G5 whilst keeping this baby.

Thanks all


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## dawgdan (Aug 10, 2006)

"Acceptably" is a subjective term.  I ran an IDMAX acceptably with it, a relatively power-hungry sub probably not far from the G5. 

I would be pleased.


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## FunkyJam (Jun 5, 2009)

Thanks bro. Do you think running (4) SX65's on it with the G5 would be pushing it? For now I'm planning on letting my rear fillers stay off the amp.


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## FunkyJam (Jun 5, 2009)

Actually, that's a stupid question, because the SX65's will be running off different channels than the sub anyway, so they won't be affected.


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## dawgdan (Aug 10, 2006)

Well you could run the second set in parallel with the fronts but you'd lose fader ability.

Or just go all in and don't worry about rear speakers like the rest of the dark side. Come on over.


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## ouchouchouch (Dec 2, 2011)

Quite confused about the specs but would this be able to run 1 x t3652s and 1 x t2652s? Or will the t600.4 be a more suitable option?


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## Angrywhopper (Jan 20, 2010)

ouchouchouch said:


> Quite confused about the specs but would this be able to run 1 x t3652s and 1 x t2652s? Or will the t600.4 be a more suitable option?


If your budget allows, I would go with the T600-4. But this amp is no slouch, it works great. Btw, OP reviewed the older T400-4. The new ones looks much better and is much smaller.


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