KPA500 Vs. ALS 600

[VE4BLB]

Have there been any comparisons made between the Elecraft KPA 500 and the Ameritron ALS 600 amplifiers?
I have the Ameritron on order but that Elecraft seem a better amp. Good video on their site of the ARRL engineer testing it.

[N7WR]

I would take anything made by Elecraft over that made by MFJ

[WB2WIK]

The KPA500 is self-contained (RF amp and power supply in one box), so it's smaller and easier to place or transport.

Power output is about the same. And it might be more "foolproof" since it has a frequency counter in it that does automatic band switching when it senses the drive frequency (in milliseconds). I believe it also comes with 10/12m coverage right out of the box, whereas the ALS requires a field modification to use those two bands.

As such, I'd go with the KPA.

[KK7EL]

BLB (Bruce):
Wish we had hooked up before you ordered new ALS-600 as I am about to replace my ALS-600 with Elecraft KPA500 (and KAT500 "tuner"). I would have sold it to you for US$800 and you pay shipping (and tell me how to ship to Canada). Oh well.......

[W9GB]

Wish we had hooked up before you ordered new ALS-600 as I am about to replace my ALS-600 with Elecraft KPA500 (and KAT500 "tuner").
I would have sold it to you for US$800 and you pay shipping (and tell me how to ship to Canada). Oh well.......

BLB can return it to MFJ or the dealer he purchased it from (unopen).

K9EWK (sk) purchased the ALS-600 several years ago, when first offered by Ameritron (replaced his Alpha 76).
He had the standard problems with new Ameritron/MFJ products.
Poor silk screening of front panel -- they eventually shipped him a good one.
Burned out bulbs/LEDs, failed meter board, poor assmebly soldering.

For the same reason Steve (WIK) pointed out -- the KPA500 is self-contained (power supply and amp) in ONE box.
The KAT500 tuner is one advantage, as well as "newer" design (uProcessor control of functions).
Elecraft's QUALITY is very good -- I have not heard any issues.

The Ameritron ALS-600 HF amplifier has been on the amateur market for over a decade.
There have been 2 consistent complains from owners (stated in Internet reviews):

1. Heavy linear power supply. This was addessed a few years ago with the lighted SMPS option
2. No antenna tuner offered by Ameritron/MFJ, as an add-on option for this amplifier. SO, your antenna has to be 2:1 SWR of below for operation.

w9gb

[N0AZZ]

I had a ALS-600 it failed 2 times in the first 4 months that I owned it the last time it came back I sold it in the box with the remaining warranty to a ham in my club. He had it 5 months and it failed again very low power output and they wouldn't fix it. He had to do it on his dime when he got it back he sold it.

If it were me I would return it and buy the KPA500 and even more reason if you have a K3.

[KK7EL]

I had a ALS-600 it failed 2 times in the first 4 months that I owned it the last time it came back I sold it in the box with the remaining warranty to a ham in my club. He had it 5 months and it failed again very low power output and they wouldn't fix it. He had to do it on his dime when he got it back he sold it.

Looks like a classic case of "your mileage may vary". I have had my ALS-600 since 1997 and I bought it used (made May 1996), no issues in the ~14 years I have owned it, but did recently elect to replace the input swamping resistor (R301). I do not use the amp often, but when I do it is somewhere around 550w out.

Still, I am going to sell it and get a KPA500 and KAT500, but primarily because they all play nicely with my K3, not because the ALS-600 is bad or troublesome.

[KM1H]

Neither amp has exceptional IMD from a lot of owners comments Ive read but neither does the K3. Never tried either.

Carl

[AC0H]

Neither amp has exceptional IMD from a lot of owners comments Ive read but neither does the K3. Never tried either.

Carl

There are a lot of radios with 12V finals with less than stellar IMD perfomance. Still hoping for the manu's to switch to 28 or 50V finals but there's a HUGE installed base of 13.8V power supplies out there. SS amps are always going to be at the mercy of the quality of their low pass filters when it comes to IMD.

I read this the other day when pondering building my own 600W class amp from one of CCI EB-104 kits.

http://www.qsl.net/wm5z/qex199907.pdf

Sounds better than the typical LPF used with SS amps.

[N4FBW]

The KPA500 uses a 50V + power supply. AFAIK, the only amplifiers that still use 12V finals are the one's for mobile operation.

There are a lot of radios with 12V finals with less than stellar IMD perfomance. Still hoping for the manu's to switch to 28 or 50V finals but there's a HUGE installed base of 13.8V power supplies out there. SS amps are always going to be at the mercy of the quality of their low pass filters when it comes to IMD.

I read this the other day when pondering building my own 600W class amp from one of CCI EB-104 kits.

http://www.qsl.net/wm5z/qex199907.pdf

Sounds better than the typical LPF used with SS amps.