Infinity Vs Rockford Fosgate

[GALLA_4]

Narrowed my AMP search down to these two below. The infinity is cheaper but with higher RMS (111rms) and the RF amp is dearer with less RMS (100rms). However would the build quailty of the RF be better than the infinity one? Anyone have hands on experience with either of these models or brands?

Infinity: REF-7540A - Amplifier

4/3/2 channel amplifier

Power Output:

111 watts RMS x 4 channel at 4 ohms and ≤ 1% THD

278 watts RMS x 2 channel at 4 ohms, 14.4V supply and ≤ 1% THD

Signal-to-Noise Ratio: 81dBA (reference 1 watt into 4 ohms)

Dynamic Power: 164 watts at 2 ohms

Effective Damping Factor: 6.315 at 4 ohms

Frequency Response (-3dB): 10Hz to 100kHz (-3dB)

Maximum Input Signal: 5.5V

Maximum Sensitivity: 230mV

Output Regulation: .088 dB at 4 ohms

RRP £249.99

OR

Rockford Fosgate: Punch P8004 Amplifier

100 W x 4 @ 4 Ohms RMS

200 W x 4 @ 2 Ohms RMS

400 W x 2 @ 4 Ohms Bridged RMS

Crossover : LP 40-400Hz 12dB per Octave

HP 40-400Hz 12dB per Octave

Bass Control - 0 to 18 dB @ 45 Hz

Wired Bass controller included

Low level RCA Signal input. Voltage - 250mV - 6 volts

4 gauge Power Wire input

Protection built-in

Frequency response : 20 to 20k Hz +/- .5 dB

S/N 100dB A-weighted

Damping Factor >200

Slew Rate 30 Volts/ms

IM Distortion <.08%

Stereo/mix frequency response: 20 to 20k Hz +/- .5 dB

Dimensions : 2.4 X 11 X 17.7 (inches)

POWERING THESE:

FRONT

6½" (160mm) 2-way component system.

CMMD. PlusOne.

Passive crossover.

90w RMS

270w max power

REAR

6 x 9 - 3 way speaker

Peak power: 330 W

RMS power:110W

Voice coil: 4Ω

Sensitivity: 90dB

Frequency response: 35Hz - 22kHz

Mounting Depth: 81mm

Cut-Out Diameter: 150mm x 221mm

[legendswraith]

Narrowed my AMP search down to these two below. The infinity is cheaper but with higher RMS (111rms) and the RF amp is dearer with less RMS (100rms). However would the build quailty of the RF be better than the infinity one? Anyone have hands on experience with either of these models or brands?

Infinity: REF-7540A - Amplifier

4/3/2 channel amplifier

Power Output:

111 watts RMS x 4 channel at 4 ohms and ≤ 1% THD

278 watts RMS x 2 channel at 4 ohms, 14.4V supply and ≤ 1% THD

Signal-to-Noise Ratio: 81dBA (reference 1 watt into 4 ohms)

Dynamic Power: 164 watts at 2 ohms

Effective Damping Factor: 6.315 at 4 ohms

Frequency Response (-3dB): 10Hz to 100kHz (-3dB)

Maximum Input Signal: 5.5V

Maximum Sensitivity: 230mV

Output Regulation: .088 dB at 4 ohms

RRP £249.99

OR

Rockford Fosgate: Punch P8004 Amplifier

100 W x 4 @ 4 Ohms RMS

200 W x 4 @ 2 Ohms RMS

400 W x 2 @ 4 Ohms Bridged RMS

Crossover : LP 40-400Hz 12dB per Octave

HP 40-400Hz 12dB per Octave

Bass Control - 0 to 18 dB @ 45 Hz

Wired Bass controller included

Low level RCA Signal input. Voltage - 250mV - 6 volts

4 gauge Power Wire input

Protection built-in

Frequency response : 20 to 20k Hz +/- .5 dB

S/N 100dB A-weighted

Damping Factor >200

Slew Rate 30 Volts/ms

IM Distortion <.08%

Stereo/mix frequency response: 20 to 20k Hz +/- .5 dB

Dimensions : 2.4 X 11 X 17.7 (inches)

POWERING THESE:

FRONT

6½" (160mm) 2-way component system.

CMMD. PlusOne.

Passive crossover.

90w RMS

270w max power

REAR

6 x 9 - 3 way speaker

Peak power: 330 W

RMS power:110W

Voice coil: 4Ω

Sensitivity: 90dB

Frequency response: 35Hz - 22kHz

Mounting Depth: 81mm

Cut-Out Diameter: 150mm x 221mm

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will be interested in the results of this post as i appear to have the same speakers but i have component ones for the front and another set for the rear doors and some of the 6x9s for the back do you need a mid for the front on yours or is it different lay out from the GS as i only need one mid for the front which will leave me a spare one if i buy them and i have my eye on a set of kappas at a very reasonable price ;)

[GALLA_4]

I have two tweeters(behind wing mirror housing) and two mids up front (in the doors) and those monster 6x9's in the rear deck.

But which AMP?

[marx]

I have two tweeters(behind wing mirror housing) and two mids up front (in the doors) and those monster 6x9's in the rear deck.

But which AMP?

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lOOK AT THE DISTORTION RATING AS 1% IS GOOD BUT THR ROCKOFRD MAYBE LOWER, EITHER WAY I'VE WOULD LISTEN TO BOTH WITH SOME OF THE TYPES OF TUNES YOU'D NORMALLY LISTEN TO AND WHICH IS MORE DURABLE!

[SHAHZ]

As said before if you can, power them both up and see what sound better, i personally would favour the Fosgate ;)

[Diapason]

Hi Galla,

I don't know anything about car audio, but I'm a bit of a hifi nut. Now, you can pretty much never tell how something's going to sound from specs, but one thing jumps out looking at the above sets of figures. An amp with good current delivery should double its power as impedance halves. The Rockford does, the Infinity doesn't. That's no guarantee of good sound, but it's a sign that the sound *shouldn't* get too strained when the going gets tough.

It's worth nothing is that the figure given for impedance of the speakers is a "nominal" figure. Impedance of a speaker changes depending on the frequency of the signal. For all we know, the speaker dips to 2 ohms at certain frequencies which will cause an amp without good current delivery to struggle. That's why I'd lean toward the Rockford based on the specs

Incidentally, in my opinion the difference between 111 and 100 W isn't worth talking about.

Of course, you could always go for the amp pictured in my avatar. I've never heard it, but it looks cool! Maybe a little expensive, though...

Si

[Mr Singh]

I have two tweeters(behind wing mirror housing) and two mids up front (in the doors) and those monster 6x9's in the rear deck.

But which AMP?

←

lOOK AT THE DISTORTION RATING AS 1% IS GOOD BUT THR ROCKOFRD MAYBE LOWER, EITHER WAY I'VE WOULD LISTEN TO BOTH WITH SOME OF THE TYPES OF TUNES YOU'D NORMALLY LISTEN TO AND WHICH IS MORE DURABLE!

←

Funny that, can you hear 1% Distortion? :winky:

Hell if you can, you can take my job :)

Both amps will do the job fine, i REALLY doubt there is any sonic difference's in the two amps.

They are built under same kind of budget and target audience.

@ Diapason - Thats a SoundStream Human Reign amp. Not as good as they used to be, back in late 90s, however product quality slips as more and more companys are being bought out by people out in Asia.... Its all about Profit margins % rather than quality....

RF incidentally is manufactuered in China now, along with 90% of the car audio amps out there.

[Diapason]

Funny that, can you hear 1% Distortion? :winky:

Hell if you can, you can take my job :)

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Hey mate, do you mind me asking what you do? Are you involved in audio/sound engineering? That's something I always thought I'd be really interested in. Granted I'd probably be turd at it, but still...

@ Diapason - Thats a SoundStream Human Reign amp. Not as good as they used to be, back in late 90s, however product quality slips as more and more companys are being bought out by people out in Asia.... Its all about Profit margins % rather than quality....

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Indeed, well spotted!! It seems like all audio, be it car or home, is moving to China. Of course, I'd be happy if we could get hifi even at the prices they pay in the US. It's funny how the currency symbol on the pricetag seems to change from $ to £, but the number after it doesn't.

Si

[Mr Singh]

I run Car Audio Distribution company. We import mainly high end Made in USA products.

Also responsible for the loudest car in the UK plus several SPL UK Records as well as competitors in IASCA SQ Formats.

:)

[Diapason]

Also responsible for the loudest car in the UK plus several SPL UK Records as well as competitors in IASCA SQ Formats.

:)

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SWEEEEET!! :D :D :D

Sorry to hijack your thread Galla. Back to business...

Si

[GALLA_4]

I am kinda being lead towards the RF Amp now that I have read all the above. Interesting!!!