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Moleculo 03-21-2011 07:41 PM


The replacement amplifier arrived today! I've hooked it up and run a quick test and everything is functioning normally, on 10 meters also. Stay tuned for the continuation of this review

TonyV225 03-22-2011 07:47 AM

I lovw my ALS-600 its so easy to use along with being bullet proof with all its protection circuits. Im am diaapointed to see thios ALS-1300 failed on you maybe luck of the draw ?? Well hopefully anyways.

I loved the 1300 when you first posted the pics from Dayten ham convention but then seen the price tag and OUCH!!! I agree with Rich (DXHOUND) and it would be nice to see this atleast hit legal limit.

I was looking at the ALS-1300 lastyear and looked at what I could get in a tube amp at that price and thought geeze I can get double the power and idle at legal limit allday.

I then took into consideration the ease of use the solidstate ALS-1300 has and do agree its a completey different animal and really cant be put into a category with a tube amplifer. I would still like a 1300 like this because I do as I said love my ALS-600.

I guess in the end it boils down to what a person is looking for between monster power or closse to legal limit with ease of use and a sure fgool proof innerprotection circuit to save the unit incase of the occasionally oopsy did I do that scenario.

Ide behappy with the 1300 Im sure and if you think about it who the hell is ever going to see or hear the diffrence between 1,200 - 1,300 watts and 1,500 Im anxious to see the rest of this review with the new amplifier which Im sure will be trouble free.

Moleculo 03-23-2011 09:18 PM

I had some time to do a bit of testing tonight and I finished the power output matrix I was working on. Admittedly, I should have started over because it's a different amp, but I wanted to just go ahead to see if I could discern much difference between the two. Basically, what I learned is that there is some difference in the power output between the two, but nothing that seems unusual.

Power was measured on CW using a Bird 43P. I set the input power using either a 50 watt or 100 watt element, checking it on each band, then switching to a 100 watt, 250 watt, 500 watt, 1000 watt, or 2500 watt element as appropriate for the amplifier output.

Here is the power output matrix. You can probably figure out where the numbers change between the old amp and new one by studying the table, but it doesn't really matter that much.


An interesting phenomenon occurred on both amplifiers while testing: The initial power output spikes and then "settles" over about 5-10 seconds. On the high power levels, the difference between key up output power and "settling" power can be as much as several hundred watts. I double checked the output power of the exciter by itself and didn't notice this behavior, so it is definitely something that the amp is producing. While this is not really a problem, it is an interesting observation.

One thing to quote from the manual:


While this amplifier will run more than 1200 watts PEP output, linearity will suffer. Ameritron recommends running no more than 1200 watts peak power for maximum linearity, where this amplifier will have comparable IM performance to the best vacuum tube linear amplifiers.

Moleculo 03-23-2011 10:33 PM

Bad news (again) tonight.

While doing the power output testing into a dummy load, I observed some strange behavior. The problem was that the amp would trip off into protection mode when sending a CW tone for around 10-15 seconds on 10 and 17 meters, and also on 20 meters after about 20-30 seconds. It didn't seem to matter whether or not the drive level was 25 watts or 100 watts, it would still trip into protection. I verified the dummy load VSWR without the amplifier before and after the tests. After tripping to protection, I was able to reset it by flipping the OPERATE button to STANDBY position and then back, after which I could go back to normal operation.

I thought that perhaps the problem was an RFI problem caused by the dummy load being too near the power supply and amplifier, so I switched to external antennas. In each situation, I carefully checked the SWR presented to the amplifier and touched it up if necessary using the Ameritron ATR-30 tuner which is between the amp and the antenna. On the 10 meter inverted V antenna, I had the exact same problem: The amp tripped to protection mode after a few seconds. Next, I switched over to a Cushcraft R6000 at 42 feet to the feed point and performed the same test. On this antenna, I had no need for the tuner and tested on 28.935Mhz, where the VSWR is 1.3:1. After only a couple of seconds, the amplifier shut itself down. It now will not turn back on, exhibiting the exact same behavior as the previous amplifier: When you turn it on, the left ammeter needle quickly swings up to 25 amps, and then shuts back down without the amplifier ever turning on.

When I initially noticed the problem of the amplifier tripping into protection, I observed the PAB meter which measures the difference in power output between both PA's, and only saw a difference of about 10 watts or so. This is an important check because the manual says the the amplifier will trip into protection if there is a difference of 200 watts. Obviously, this doesn't appear to be the problem. I also checked all of the other meter measurements and noticed nothing unusual.

I'm not sure what to report to Ameritron that will help troubleshoot the problem, except that I routinely use my AL-800H at legal limit and have no problems. When the ALS-1300 was operating properly on 10, 17 and 20 meters (before it tripped protection mode), the power output was as described in the manual.

Ameritron had the first test amplifier sent to W8JI for troubleshooting...hopefully he has found something useful that will help identify the problem. Obviously the problem I experienced initially is not a fluke.

I'll update everyone as I find out more from Ameritron.

AE6RR 05-06-2011 02:17 PM

ALS-1300 10M problem
I had the same problem, I started with 500W output on 10M and started increasing the drive. Somewhere around 800W output something went BANG and the amp went dead. Both 15A fuses on the 240V mains were blown, after replacing the fuses, I found that one 50V supply was dead. I returned the amp to Ameritron and they repaired it. They replaced the power supply board and 4 MOSFET finals.

When I got the unit back there was a note that said not to exceed 25A supply current on 15, 12 & 10M.

I now can get full power out on all bands except 10M with 25A supply current. On 10M with 25W of drive, I get 25A and only 650W output. I suspect the 10/12M filter as being the problem.

Did Ameritron ever tell you what the problem was?


Originally Posted by Moleculo (Post 259124)
An interesting turn of events last nite...

I was testing the ALS-1300 into a dummy load at various drive levels on each band, preparing a drive/output table for this review. When I tested the amp at 25 watts on 10 meters (about 500 watts output) the amp started tripping into protection mode. Then when I tested it on 10 meters with a little less than 100 watts drive, the amp and power supply shut down and now it won't power on.

I'm in contact with the folks at Ameritron and they are going to send another amp and take a look at this one to determine what might have caused this problem. I was really digging this amp until this issue, so I'll be interested to see if I can replicate the problem on another unit, or if things will continue on without issue.

More to come...

Moleculo 05-09-2011 03:44 PM


Did Ameritron ever tell you what the problem was?
I just got a note from them that they have another amp that they are going to send which has some changes applied. I'm waiting to hear what those changes are and do further testing. Stay tuned...

kd-5-bgt 05-11-2011 05:39 AM

I used to think that Ameritron put out good high quality equipment...but after 2 amps in a row that were found to be defective I am beginning to wonder just how many units has been sent out to folks with those problems

I hope they get this sorted out for you Moleculo

TonyV225 05-11-2011 11:55 AM

I have had good luck with my ALS-600 but then again I have the older model without the remote head hookups its a great amplifier.

I have an older AL-84 that has to be repaired but this amp was put away and unused for sometime and is now in need or part replacements.

That sucks and is scary that this 1300 is at the cost it is at and is problems!! :crying::unsure::thumbdown::cursing:

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