There is nothing illegal about the amplifier as long as
you have a ham license and use it on amateur frequencies
you are licensed for. Where it becomes illegal is if you
use it on CB frequencies. Not having a filter does not
make the amplifier illegal, although if you were a
consciencious person, you'd probably want to put
a low-pass filter on the amp's output. A clean signal
in would give you a clean signal out. Also, you want
to make sure it's class A, AB1, or AB2 if you want to
use it for voice. If it's class C, as many solid state
amplifiers are, it's only good for FM or CW. It is
possible to have a solid state amp and it be class AB2.
AB1 is usually a tube amp. If you use a class C amp
on SSB, it will show distortion, and this will cause you
to have spurious harmonics and you will interfere with
others on the band (and also possibly out of band too).

73, -Web, KR4WM
o.k. whats your opinion on this information.

IS the KL-400 amplifier made in Italy legal in the USA on the ham bands? Here are the stats: KL-400 LINEAR AMPLIFIER WITH PRE-AMP
RM ITALY

    * Frequency: 3-30MHz
    * Input energy/power: 12-24 A
    * Input power: 1-10 W AM/FM
    * Input power: 2-20 W SSB/CW
    * Output power: 200 W Max AM/FM
    * Output power: 400 W Max SSB/CW
    * Mode: AM-FM-SSB-CW
    * Fuse: 2 X 12 A
    * Output power level: 6
    * Size: 170x210x62 mm
    * Pre-amp: 26 dB on reception
    * Electronic Switch
    * Inversion Polarity protection

hi Brent, this is John kb3hqh, I have both rigs, the Jupiter and the 746 Pro.  They are both outstanding. I find myself operating the Jupiter the most. Recieve sensitivity is tough to comment on at this QTH.  I have alot of noise here.  My dipole and vertical are within 25 feet of high tension lines. I have experiemented with the Scaf audio and Sounds Sweet speaker to eliminate 75% of it. I haven't done a antenna comparision on recieve for both rigs. I am learning to copy weak signals in noise.   It also depends on your operating style.  The 746 Pro has the twin pass band tuning which is very good for filtering noises on either side of the filter, independently I might add.  There is also 2 and 6 meters in this rig, that I don't use.  Appearance is pleasing to look at. But the Jupiter sounds just as good to me.  If you read the Jupiter reviews, you will find good and bad.  I wrote one ham and he thinks the selectivity is better in the Jupiter the the 746 Pro, and if I am not mistaken, he did antenna comparisions. Thats another thing you can do, write owners of the Jupiter. I like the way the Jupiter looks.  The excellant sound of the cw sidetone.  The filters for recieve also go down to 150 hz. And also has passband tuning.  With digital filters you get hollow and ringing if you go to low, same with the Pro. I like the clear crisp response of the Jupiter because i operate mostly entirely on cw.  I know that you can tailor the audio output on the Pro to you voice.  This is the second Jupiter that I owned.  I bought another one because i like the sound and the look of the rig.  It looks completely oposite of the 746 Pro.  Its more military looking, and some peoples opinion of the screen is outdated.  I like the screen, its big, and clear. If I had to pick one of the rigs, I would pick the Jupiter, and thats probably because i operate mostly cw.  If I operated ssb, maybe the story would be different. And another thing, the solar cycle is at the bottom, so is it a good time to pick a rig, or a bad time.  I think it is a good time for weak signal work.
And I copy alot of qrp stations with the Jupiter.