RF vs PG, The Real Deal!

I have heard many deep discussions regarding the comparison of amplifiers.  Many people firmly believe any two amps will sound the same when set up in an identical fashion. 

While cleaning up my workspace, the thought occurred to me I had the room and the resources to set up my own blind amplifier test.  I used a pair of Rockford Fosgate Power 250.2Cs in my car for a few years and one day I gave a Phoenix Gold ZX450 a try.  After that day I felt I would never go back.

To keep things fair, I decided to pit the RF 250.2C against a PG ZX500.  Both amps are similar in power, and original retail value.  The speakers chosen are a set of 8 ohm home speakers I built myself, and have been verified by others to be very flat and revealing.  I used a portable CD player for a source.  This is probably not the best choice, but I did not want any ground loop in my setup so the battery powered device would serve me well.

Both amps were wired to the same power supply, and would be on at the same time.  No amp would be given any advantage, as all leads were short enough, and they would be sharing the same voltage source.  The output of the CD player was split with “Y” cables into both amps at the same time.  Again, they would share the signal, and each would not have any advantage.  The speakers remained in the same position for the whole test.  To switch between them, I made a pair of XLR cables.  The cables were identical to each other, and the wire bunched up under the RF amp, so no one could tell what cable went to what amp.

Electrically, the amplifiers were matched.  I played a sine tone on the CD player, and set each amps gain to the same output level.  Once set, the gain and volumes were not touched.  Both amplifiers had any onboard processing disabled.  They were each set to “full range”.

For test subjects, I used myself, my parents, and a friend who is a fellow car audio enthusiast.  My mother was an excellent choice, as she could care less about what brand sounded better, and therefore was a better judge of what she preferred. 

The results were surprising.  All four of us could tell the difference between the amplifiers, and pick out their preferred amp 100% of the time.  At first, I would let each subject switch the amps themselves, and see what they liked (they did not know what amp was which, just that the liked a certain one).  Next, someone else would switch the amps for them, and randomize the switching.  The subject had no clue what amp was on, yet they could all still pick out the different amp.

Initially, I found something very odd.  The RF amplifier had much more bass than the PG amplifier.  Keep in mind I had both set flat.  The speakers were in the exact same locations for the test.  Clearly the RF amplifier could either handle the load better (8 ohm is no problem for these amps), or the RF amp had built in bass boost to it.  The bass was more pronounced on the RF, but was not natural.  To get the PG equivalent, I had to boost the bass 2db.  My assumption is the RF has added bass for the purpose of selling more amps on a showroom floor.  If a customer were running a switcher in a showroom, the increased bass from the RF may be enough to sell them on it.  I am also a bit displeased, as the bass was too boosted, and I specifically set the amplifier to be flat.

Secondly, the PG amplifier had far more depth and stereo separation to it.  So much better was it, the RF sounded mono.  I checked all the setup, played some stereo test music, and sure enough the RF was playing stereo, it just did not have the separation.  Keep in mind the Power 250.2C is a dual mono amplifier, with independent power supplies.  The PG is not.  There is no excuse for the RF to perform so poorly in this test.

(Update, the 250.2C is not dual mono as it says in RF literature, it has only one power supply)

In the end, the Phoenix Gold, was a clear winner.  It was far more natural, and involving.  The Rockford amp seemed to just “make noise”.  I should not be so harsh on the RF however, as it was highly detailed, and forceful.  I am willing to believe if I set up a pair of RF amps in a car, with one for the right side, and one for the left, the true dual mono would allow them to compete with what PG did in a single chassis.

If you have any questions about this test, or ideas as to how I can make it even more fair, please email me at dr.fosgate@soundbuggy.com

UPDATE:  It seems this "review" has made its way on to the Rockford Forum and is now being analyzed in detail.  Well, I would like to stress, this is NOT a review, but instead is the subjective opinions of 4 totally different people (as stated above).  First there is me, who once worked for RF, and sold RF product for years prior to working there, and still to this day currently own several RF amps.  (Power T5002, Power 750X, Power 800a4, Punch Power 250.2C, Punch Power 250.2C, Punch 400.4, Punch 400x4, Punch 60ix, Punch 60x2, Punch 60 DSM, Punch 4080 DSM, Power 250x2, and a Power 50x2).  Next there is my close friend who is a die hard RF fanatic.  He owns countless RF amps including 10 or more Punch Power 500.2 (1998), Punch 50.2 (maybe 10 or more of them), old HD amps, every RF processor including the original Symmetry, and a bunch of other RF stuff.  Lastly I put my parents in the mix.  My father has a Power 800a4 in his truck, with all RF speakers and what not, and my mom has PPI, JL, and Clarion in her ride.  She for the most part is not a good judge of sound quality, and prefers "bling".

The consensus amongst all 4 of us was the RF amps just don't sound nearly as good.  Now, my die hard RF friend was even willing to admit that.  But, this does not change his opinion of RF, and he intends to keep using the equipment.  RF is not junk that is for sure.  What is frustrating is it is NOT made for SQ use, even though the RF dealers and sales may try to spoon feed you that.

Since writing this I have tested SoundStream, Zapco, plenty of PG amps, and many PPI amps.  Here is the interesting part.  To me and my friends involved in some of the tests, Zapco, PPI, PG, and SoundStream all sound the same, and that sound is very good.  In an A/B test with any of these other amps, the RF amps fall short on sound quality.  They do sound great stand alone with out something to compare too, but once you make the comparison, they are really lacking.  On a side note, I tested a SoundStream Class A 6.0, and it was (in my opinion) the best sounding amp I have tested.  However, it ran far too hot for my tastes, and I would not trust it in an install without a fan or two.

My whole point with all this is to not say RF sucks, but to instead suggest that anyone willing to buy new or used RF amps (not talking speakers here), at least consider some other brand.  If you go with older used gear from the "high end" guys like Zapco, PG, PPI, or SoundStream, you get a hell of a lot more amp for your money.  Keep in mind RF marketing will tell you all that matters is "more watts", but if you enjoy music, "more watts" does not equal "sounds better".

For more information, and some other interesting stuff, please see the Elite Car Audio forum.  http://forum.elitecaraudio.com/

You will notice that RF stuff is hardly ever mentioned, and it also never sells in the classified section.  To me this is just further evidence RF is for SPL (where they are nearly unmatched), and not for SQ.