- Amateur Radio (Ham Radio) Community

Call Search

New to Ham Radio?
My Profile

Friends Remembered
Survey Question

DX Cluster Spots

Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement

Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Ameritron ALS-600 Help

Reviews Summary for Ameritron ALS-600
Ameritron ALS-600 Reviews: 192 Average rating: 4.2/5 MSRP: $1299.99
Description: 600W Output Solid State Amplifier w /Power Supply on 100/110/120V for US
Product is in production.
More info:
Email Subscription
You are not subscribed to this review.

My Subscriptions
Subscriptions Help

You can write your own review of the Ameritron ALS-600.

Page 1 of 20 —>

WQ2H Rating: 5/5 Jun 6, 2019 08:52 Send this review to a friend
Great HF Amplifier !  Time owned: more than 12 months
Have had the ALS-600 a few years now, and it's worked flawlessly on all bands (including 10m with the upgrade card). I use it with the remote switch box, and it's never failed to auto-band switch and provide a stable 500-600W. I especially like the ALS set up procedure - do it once and forget it. The fan cooling system is clearly adequate, but I upgraded the fans to higher capacity DC fans powered from an external source. (a bonus during New Hampshire winters)

The linear power supply draws ~12A @ 120Vac (the switcher even more), so my only suggestion is to use a separate 15/20A circuit for the amp. With inrush and spikes it really should be on it's own dedicated circuit.
WD5FUN Rating: 5/5 Oct 17, 2018 09:56 Send this review to a friend
Worked Flawlessly for 4 years  Time owned: more than 12 months
I have used this amp daily for 4 years without any problems. It consistently puts out 550 watts with 60 watts input. It will run more that 600 watts with 100 watts input, but that gains you pretty much nothing. I use it with an ARI-500 so it is like using a 500 watt radio, no adjustments at all. Problems my friends have had with this amp have been user problems not amp problems.
K7JOE Rating: 4/5 Jul 16, 2018 21:58 Send this review to a friend
Works OK, but some issues  Time owned: more than 12 months
Have two of these solid state amplifiers used with Icom IC-7300 radios. On the used market, these go for around $900, or approximately $1.50 per watt. The power output on these amps is a steady and dependable 500W on most bands. I never see more than that, and on some bands, the best this amp will do is around 450W. I like that it covers 160-10M, which many tube amps will not cover 160 (or 10M).

The amp, as others note, requires very good Vswr of less than 1.2:1 for proper performance. I use the LDGAT600 ProII tuners with the two ALS600. These tuners auto-tune but seldom stop at a 1:1 match...they find 1:1 at low power but when the amp is turned on the match is usually 1.2:1 or higher. This occasionally causes an amp fault / protection.

The amps that I have (two) are both with the linear power supply. One has an RttY/Normal switch, the other does not. Both are heavy weight linear power supplies.

It does not require any separate relay or interface box to connect to most modern HF radios. No high voltage on the relay line, so very simple RCA jacks for plug and play.

The power curve is as noted by another user - with 40W in, I see around 280W peak watts out. With 70W in I see 450W peak out, and with 90-100W in, I see 500 W peak out on some bands, but not all.

The open frame relay causes problems and requires regular use of de-oxit, or replacement with sealed DIP relay kit (sold by AD5X) which I did to one of the two amps. This kit works up to around 35WPM, making it possible to have QSK for contesting and dxing, but the Icom radios that I use have noisy and slow relays inside so I dont use the QSK feature much - the relay mod is better for longevity though and seems to work ok.

These amplifiers, as others have noted, are not "instant" bandswitching unless your antenna is perfectly matched (1.2:1 or less); If you use an auto-tuner, or a manual tuner to tweak the VSWR of your antenna, you wont save much time with the fast solid state tuner.

I've found these amps to be good "casual" amplifiers for CW use, I do not do much SSB but can NOT get the proper ALC action out of the ALS-600 as described in the manual. The issue is that the ALC voltage calibration of the ALS600 is incorrect for the feedback required by the ICOM IC-7300 (my radios); The feedback voltage is too low - I see the IC-7300 fold back a slight amount, but can never get the ALC light to turn yellow despite front and rear panel adjustments. For other radio's, it may work better. I am very careful to observe the settings of the power control.

The amp will load-fault for me even on resonant antennas at anything over a 1.5:1 VSWR, every time.

It seems to be happiest being driven at around 50-60w PEP to approx 400W PEP output. Driving it with higher power is reported to degrade/damage the 35-ohm non inductive carbon 100W damping resistor in the PA input circuit. I've heard guys have problems with this resistor;

On air, with the 400W or so output, you're just not gaining a lot - 6 dB or so, and for that I would not pay the new price going rate for this amp;

At the used price of $800-$900, it's an OK alternative to heavy, noisy, high voltage amplifiers. It is far better than the "peanut whistle" 572B and 811a-based amps, some of which are approaching 50 years of age; the early ameritron ALS-600 amps were built before MFJ bought the company and seem to be of slightly better build quality - no they do not have the remote connections on front, or the switching power supply that the later units have, but construction seems to be better with fewer cold solder/QC issues, serial numbers below around 14,000

The fan noise is not objectionable when keeping the RF deck on the desktop and the power supply under the operating desk. The lamps in the power supply meter do seem to quickly burn out... switching to LED lamps might help. I did that LED lamp swap for the RF deck meters and they look nice.

Bottom line: an honest 450-500W PEP solid state desktop amp capable of SSB and CW, or 300W in rtty mode in a compact 2-piece package. A nice upgrade from the cheaper 811/572 based amplifiers that can be keyed without interface from a modern radio, although sensitive to VSWR so requires use of a very well tuned resonant antenna, a manual antenna tuner, or an auto-tuner that has been "dialed in" with the settings to provide a rapid 1:1 VSWR at full amp output power. For $1500 bucks, it's very expensive. For half that, it's a good buy and can be useful to provide approx 6 dB gain (1 s-unit) to your transmit signal.

W1ES Rating: 2/5 May 18, 2018 18:46 Send this review to a friend
Protection Needs Help  Time owned: 3 to 6 months
The amp worked flawlessly when it worked. It was an earlier version (with the band switch and the larger SPS). The problem, for me, was if you forgot to change that bandswitch, it blew up spectacularly, instead of shuttng down and STAYING protected until idiot me could figure it out.

Sent it to Ameritron (good service experience) and, $500 later it worked for a few months.

Ran it on 30m one night, at reduced (200W) output with about a 1.8:1 VSWR showing on its meter and it just DIED. Didn't protect. Just. Died.

I'll not be an idiot and spend another $500, so I sold it as not working on eBay and went back to tubes. I'd love to have another SS amp, but not this one.
NE2Q Rating: 1/5 Mar 29, 2018 13:22 Send this review to a friend
Poor Soldering & Overall Construction  Time owned: 6 to 12 months
Poor wiring. Many wires not wrapped around terminals but simply "tack soldered" in place. This can result in unneeded failures.

Unit failed after a few months. Inspection revealed unsoldered components.

Loose components require user tightening. The wiring & soldering appears to be done by untrained workers.

Obviously there is no Quality Control, which is common among all MFJ owned brands.

If you cannot afford quality products and you are good at repairing electronic items, MFJ products may be suitable for you.
N2UJN Rating: 4/5 Dec 22, 2017 10:59 Send this review to a friend
Updated ALS-600 input/output pwr link  Time owned: 3 to 6 months
In the previous review post, for some reason, the link to the graphical results for power in/ power out does not resolve. Here is an updated link:

ALS-600 Power Input/Power Output Characteristic
Audio Input.
N2UJN Rating: 4/5 Dec 22, 2017 04:59 Send this review to a friend
Good 400-500W Amp  Time owned: 3 to 6 months
I purchased a used ALS-600, a later model with A B REMOTE ports on front, with new finals from Ameritron in late September of 2017. Detailed power input/output characteristics reported in this review below.

In four months of various testing and use on all bands I have not had a "problem" with the amp. I gave the amp a 4 instead of a 5 because: a) to really achieve 600 Watt output routinely on 10m-40m you have to run at or near 100W input. However, running at 100W input, all the time, is reported to cause the input resistor attenuator to degrade with time, ultimately causing component failures downstream of that resistor. b) Also, with new finals, for me, and, for many others, the power output on 80m peaks at 500W with 100W input. Extensive power output testing shown below.

IF you are looking at a highly capable amp to run continuously at 450-500W, and achieve long FET life, then, this amp IS a 5. But, advertised 600W output coupled with extended long life, based on all reported data, is a bit of a stretch. Hence, the 4.

I have tested the amp both with the ALC and without the ALC. A proper adjustment procedure for setting the ALC for the ALS-600 may be found at:,69246.msg503528.html#msg503528

My audio signal is clean with or without use of the ALC on the amp assuming I have properly adjusted the ALC on the radio when not using amp ALC and properly adjusted the ALC on the amp when using it. Also, the input output power characteristics are identical with and without use of the ALC, except, with ALC the power output is controlled by the ALC SET control on the front of the amp (after setting the radio input power level high enough to reach target operating output power).

Some points of observation:
1) The amp does (by design) fault if the reflected power exceeds 50W, which, if you are running 450W out, is an SWR of 2.0.
2) I use the amp together with an old Dentron Monitor Tuner higher power tuner. My antenna's SWR does change as a function wx (wet, snow, dry, etc.). I could probably get by without the tuner most of the time, but, not all of the time. In the case of a tuner with a bypass, then, the full benefits of solid state can realized (no need to tune SWR at each frequency). Otherwise, with a tuner, ALS-600 use is very similar to a tube amp. Each frequncy has to be trimmed to match the antenna impedance.
2) The amp also (by design) faults if: the band switch is left at a lower band frequency than the actual operating frequency. (ex: bandswitch set at 2.3-4.4, actual op frequency is 14.225 MHz).
3) The amp does not fault if the bandswitch is set above the operating frequency. (ex. bandswitch set to 8.0-14.5, actual op frequency is 7.225 MHz).
4) At least for me, fan noise (amp and PS) mandates the use of a headset (Yamaha CM500). With a headset, no problem.

Power Output Characteristics: ALS-600
During my own reviews of this amp prior to purchase I could not find a detailed power characteristic published for the ALS-600. I have carefully developed, for my amp, the power input/output characteristic curves in Watts for 20m, 40m, and, 80m bands for audio input. A graph showing these curves may be found at the below link. These data are in approximate agreement with the 90W input data reported by AD5X.

Tabular Power Characteristic Data is below. I hope this helps folks......I see a lot of different single data reports like "35 Watts gives me full output". I doubt those reports greatly, unless someone has removed the input resistor attenuator. I hope this data helps folks trying to decide to buy this amp or not.

Note, there is a reference on the web that shows how to mitigate the measured and commonly reported lowish power output on 80m with cap bridges. It does not really bother will leave it.

My serial number: AL-600-16059 (has remove A/B inputs on front).

Tabular Power Data

20m (Watts)
0 0
10 45
25 125
50 350
60 425
75 550
100 625
K9HKS Rating: 3/5 Dec 5, 2017 05:55 Send this review to a friend
Problems but solvable  Time owned: 0 to 3 months
Purchased the ALS 600S Amp.Low output around 400 watts.Within a few weeks no output. Called Ameritron and after trying several suggestions I had to send it in for repair. All finals were replaced. Reason given was Chinese finals. Turn around time after repairing was great. Now have problem with meter lamp in switching power supply burning out. Ameritron sent me 3 replacements. Burned out again waiting for new one and they are adding a resistor to try to fix problem. I like the way the amp performs but it has not been real reliable.Its still in warranty and Ameritron so far has tried to resolve the problems.If I could do it over I would not buy the switching power supply
PA3GEG Rating: 3/5 Dec 4, 2017 16:15 Send this review to a friend
ALS 600 update  Time owned: 0 to 3 months
Well here I am again. After 5 weeks I called my dealer in the Netherlands if my ALS 600 was already repaired. They could not find the problem because the finals were ok, so probably problem with the print. They made me an offer I should pay 115 euro's and they would send me a new one, but now with the switching power supply. I found it a good deal and I think but I am not sure perhaps Ameritron told them to do so, but it could also be the service of the dutch dealer/importer. The power supply is more silent than the heavy linear type, but the amplifier itself Ameritron claims it is extreme quit, this is not the case it is quit noisy in my opinion. When the amp gets warm the power supply makes a strange noise even when the little fans inside are not in use. that is silenced after cooling down, A phone call to Ameritron doesn't give a solution. So I think I stay with it for now. It shows up after longer qso's in cw 200 watts after 15 minutes, in ssb 400 watts about half hour. My impression of the ALS 600 is for about 300 400 Dollars more I think you get a better product from a different company with everything in one apartment so not an external power supply. For me to be honest my last Ameritron. In the future I will try a different company, I suffer from Tinnitus so it could be when this noise irritates me to much I will get rid of it and try something else. The power is ok it gives about 600 watts in a dummy but I am only allowed to make 400 watts pep maximum in The Netherlands. I must say this amplifier section makes no strange noises when it is getting warm no thicks, the other one did when it got hot. main Problem from the Ameritron company is the should test their amplifiers better before they are shipped to the custumors.
PA3GEG Rating: 2/5 Oct 5, 2017 03:15 Send this review to a friend
finals blown out  Time owned: 6 to 12 months
I liked the amplifier at the begining, but now after 10 months the power went doen I only have 300 watts now, likely one pair of mrf150 died. I have send it too my dealer and hope they willfixe it under warranty. Don't understand it, it always worked good, protection worked and I don't push it to hard, only 400 watts legal output here in The Netherlands. I will send an update as soon I will have it back.
Page 1 of 20 —>

If you have any questions, problems, or suggestions about Reviews, please email your Reviews Manager.