Jl 300/4 vs. RF T400-4 for 3 way duty...

[Ekeko 10+ year member]

Hi!

I am considering installing a 3 way system in my CRV: Vifa/ADS front components (homemade serial x-overs), RF T400-4 (mini-amp) & 1 x Eminence Audio Lab Sub (10").

Would replacing the RF T400-4 for a JL Audio 300/4 give me better channel separation & smoother highs? Will the JL's 150 W still push my Sub well (the t400-4 does a better job in this respect that many dedicated Sub amps...!!!)

Thanks!

Manny.

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[BringDaBoom 10+ year member]

Hi!
I just got done installing a 3 way system in my CRV: Vifa/ADS front components (homemade serial x-overs), RF T400-4 (mini-amp) & 1 x Eminence Audio Lab Sub (10").

Would replacing the RF T400-4 for a JL Audio 300/4 give me better channel separation & smoother highs? Will the JL's 150 W still push my Sub well (the t400-4 does a better job in this respect that many dedicated Sub amps...!!!)

Thanks!

Manny.

Can't speak on behalf of the RF. I've owned a 300/4 and it was awesome. My mids and highs came in crystal clear and smooth. The mid bass lines were tight and smooth, and pretty loud as well. No distortion (had JL VR's as well.) It's got every concievable tuning adjustment right on the amp to dial in frequencies.

The other two channels bridged for the sub will push it fine, but IMO not as well as a class D amp designed for subs. The available bass adjustmentns and controls on the 300/4 aren't the same as say the 500/1.

 

[Ekeko 10+ year member]

THANKS!

LOL ...considering your logo, I should have been expecting the aswer tough...

No doubt that the 300/4 is an awesome amp & one of my favorites (still love my DCA 3500 class A ) but I was just curious about the new Power amps. My local dealer sells ZAPCO, XTANT, MOREL & other fancy gear but he couldn't say good enough things about this new RF amps (HE HATED THE SOUND OF THE RF SILVER AMPS BTW).

In paper it looks like the T400-4 would have quite a bit more power to motivate a sub and also I was hoping for an easier load on the electrical (vs. the regulated supplies, which the installer says are hard on the system)...

I know the JL is awesome, I was just hoping someomeone has heard these new RF amps too & if they are anywhere near the JL's...I am just curious about other people's opinions because some many installers (at different places) have had so much praise for them.

 

[whitemax 10+ year member]

I have a T400-4, actually it's in the classifieds, and it's a solid amplifier. One thing I noticed was that even when being driven hard it did not run out of steam on dynamic material. I had some Arc Audio XXK's right before installing the RF's and went to Audison right after. I would have no problems running my T400-4 and T600-2 again. Reason I went to the Audison's was that they were a little less wide, and the connections on the sides allowed me to push them up further under my seats.

couple shots if the T400-4

 

[valter 10+ year member]

I am 90% sure that you will end up with 2 blown channels very soon. Would be better to go with 300/2 and 250/1 for example.

 

[Ekeko 10+ year member]

I am 90% sure that you will end up with 2 blown channels very soon. Would be better to go with 300/2 and 250/1 for example.

...There is only enough room to hide 1 amp in my hatchback. A visible amp is a gone amp around here...

Do you know why would the 300/4 fry? Is it a power issue, impedance load???

I am trying to figure out if ANY small floorplan 4 channel is fit to do a decent job of pushing 2 comps & a SUB...

The T400-4 & the T600-4 looked promising since both push over 270+ watts into 2 ohms...also I am getting some eq. issues with the T400-4 but it could be my own inexperience with car audio.

 

[whitemax 10+ year member]

What are your issues?

 

[valter 10+ year member]

Of course it will work, just set gains correctly, better run it on 4 ohm, mount your amp in well-ventilated area and be nice to it. Don't get me wrong, I am seeing 300/4 and 450/4 amps with 2 blown channels, which were used bridged to a sub every other day. I doubt that gains were set correctly and it wasn't 1 ohm load, but still...

Personally, I like the sound of JL AB-class amps better then everything I heard from RF. It doesn't mean that JL"sounds better", it just has frequency response more pleasant for my ears.

 

[Ekeko 10+ year member]

What are your issues?

Listening to it it seems as if t the high frequency and the bass are set up too high.

After using test tones & a RatShack dB meter I am getting a relative rise of about 6-12 db in the 50-120 region and another one above 16 khz...

I tried using my HU Eq but the steps don't overlap pefectly so I end up with some mini-bumps...tolerable but not ideal...I suppose I could get an eq but I l rather avoid using one...

//content.invisioncic.com/y282845/emoticons/wow.gif.23d729408e9177caa2a0ed6a2ba6588e.gif

 

[Ekeko 10+ year member]

Of course it will work, just set gains correctly, better run it on 4 ohm, mount your amp in well-ventilated area and be nice to it. Don't get me wrong, I am seeing 300/4 and 450/4 amps with 2 blown channels, which were used bridged to a sub every other day. I doubt that gains were set correctly and it wasn't 1 ohm load, but still...Personally, I like the sound of JL AB-class amps better then everything I heard from RF. It doesn't mean that JL"sounds better", it just has frequency response more pleasant for my ears.

Now you got me with this one...I tought that the 450/4 was specifically built to drive a sub with the bridged rear channels...300 JL watts, right?

Anybody cares to theorize what's going on, why bridged JL's have such a high failure rate?

 

[Ekeko 10+ year member]

Just revisiting to share some thoughts after a couple years.

I finally got some info on bridging the slash amp. It could have been done by using a special JL 8 ohm sub. You got 150 W from the amp by going that way.

I had the RF for a while, it actually worked well bridged (272w fr birthsheet) with a singlecoil, 4 ohm, vented, 92 dB/W (Focal) sub. Surprisingly good.

Balanced the gains as per Valter's recommendation. 90 W per channel to Polk 6500 (90dB/W) was enough for good sound...

Eventually I wanted to biamp my fronts so I moved the RF to a truck & replaced it with a 5 channel JL HD 900/5.

While the HD900 in biamp mode sounds better to my ears (also better than the 300/4), it made me realize how good the $300 dollar T400-4 was for the money.

You just have to pick efficient drivers and install them appropriately.

I had also considered a first gen Alpine PDX, but now I am glad I stayed away because of the midbass & reliability issues. I am told the problems were solved with the new generation of Alpine amps.

In retrospective, the T400-4 was the amp for the job a that time. Now that small chasis 5 channel amps are widely available, there are alternatives...

 

[Bob Saget]

slash amps are awesome //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif