JBL PX300.4

An impressive amp from JBL

Out of the box: This JBL Power amp comes in a wider VHS/DVD size box with the emblazened orange JBL colors throughout the graphics. The amps easy enough to pull out with only two sytrofoam holders. The amp looks impressive just like in the pics. Sleek and light weighted. Even my wife thought it was nice looking.

Hooking it up: Hook up was a cinch since this new amp is using the compression style screws typical of JBL amps. One gripe that I had right away was the inability to switch the amp to a mode that will allow you to bring in one set of RCA's and still play out all 4 channels. Fortunently the JBL has a output RCA set that I hooked up to the front channel input VIA 1 foot RCA cable so no need for a power robbing Y-Adapter.

Initial Listen: I'm replacing an aged MTX 4603 that works fine. It would push around 105 db on my 2 sets of JBL P650c components. When I first turned it on the input gain was set to 6V (this is the low side). I didn't follow the instructions to turn up the source to 100% then set the gain. Too lazy and tired to disconnect the speakers. I just treated the input gain as a normal gain and slowly brought it up with the source at 70%. However, I did check the I/E OPT light for peaking. Reaching 250mv (the max) the light never came on. Even though my gain was at 100% I felt like it was quieter than the MTX. So I brought the source up to 80%, then 90%, finally at 95% the I/E OPT light started blinking but the music was distorted. I never normally get above 80% on the source because of the source noise but with the JBL amp I'm able to squeeze it up to 83% cleanly. The JBL still sounded not as load as the MTX so I brought my meter out and to my surprise I was peaking 111dB with an average of 107dB, so its actually a touch louder.

Final call: The JBL amp is clean sounding. At first I was worried that I wasted my money for, what I throught was, a less loud amp but found my self mistaken. The sonic clarity that its producing from my JBL power components is show worthy, releasing me from the MTX's doldrum mids and lacking details. I would have liked to seen better controls like a normal bass boost for full range, this amp features a nice boost for Low pass applications only but in a true audio world those things must be handled by a separate processor thereby freeing the JBL amp from unneccessary coloring of sounds.

JBL amp

very strong amp that match to strong systems (not SQ) more to SPLQ, very good amp
it has very complicated cross that you dont realy need, 2 protection fuses, doesnt get heated
and knows how to protect itself
the only bad thing is that his holders are made from plastic and his size
but everything else about it is just great

Sleek-lookin\' Powerhouse

I recently (easily) installed this amp and it is currently powering a Perfect 6.1 component set and two Kappa 692.7i's.

The result is fantastic!

The power in this unit seems endless, and I'm still only utilizing half the potential...I'm afraid it'd either blow the speakers or the panels off my car if I crank it up any more :)'

Great product at an affordable price.

The Best...

i bought this amp as a factory refurb and have loved it ever since. it has endless power already overheated my crossfire 5*7's all 4 of them. have to be careful and i'm not even using it's full potential. its hard to find consistent information on it though but i talked to a a guy at jbl and he explained it, the amp was initially rated at 12 volts then when CEA came on to the scene with there standardized rating system at 14.4 volts makes it a 600 watt amp. never overheated, never shut down, its a real workhorse!!