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Reviews For: Ameritron AL-572 (all models)

Category: Amplifiers: RF Power - HF & HF+6M

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Review Summary For : Ameritron AL-572 (all models)
Reviews: 74MSRP: 2400
Description:
1300 Watts PEP SSB nominal power out on 160-15M. WARC bands and 10 Meters with reduced performance - user modified for 10/12 Meters with license. Uses four 572B tubes
Product is in production
More Info: https://mfjenterprises.com/products/al-572
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00744.1
W1RMS Rating: 2012-05-07
Great amp Time Owned: 6 to 12 months.
The A-572 works great when powered by 220 VAC. I get an easy 1000 Watt on CW as measured with a calibrated Bird 43. On SSB, depending on the drive levels, checking peak envelope power with a calibrated Tektronix scope coupled with a preciseRf HF 1.5 sampler the amplifier measured between 1250-1350 watts. Not bad for an amp that is advertised for "near legal limit" opreation. When running the amp on 110VAC, the house lights dim and the power out ends up at only 500 watts on CW. I highly recommend this amp.

73

Roger W1RMS
AA9NN Rating: 2012-03-06
Very Good Amp. Time Owned: 0 to 3 months.
Saturday went up to AES in Milwaukee and bought this amp brand spanking new! I usally never do that!...buy new...but I figured what the hell time to try new. I had one of these about 5 years ago and had the newer tubes in it(Taylor 572) worked 100% although meter was a little flakey.

This amp is latest serial ## Got it home after a stop at the "Brat Stop" with my Gal and opened it up checked all the internals, all good,did the 10 Meter Mod, and fired it up on the Bench. 2800V on the numbers! The best thing for these tubes is to let them run with no load for a bit, so took the Gal out for Sushi! and movie,Amp ran for about 5 hours. All Good! Took out the ALS600 and put in the AL572 Sunday AM.
70 watts CW on 40 Meters did 1225 watts out!
All Good, 50 watts on 15 meters did 1250!
worked all over the bands and worked the Contest and amp worked as advertised!
Input SWR is all good across the board.
Now, I bought this as I wanted a KW Plus on a 120V as I had my shack wired for 220 BUT needed 2 Circuts so I have 2 30amp 120V's in my shack.
and for the price, its a solid amp! I will take 1200 to 1300 watts for over $1K less than a AL1200.
all the best and have fun!
73!

Jim AA9NN
AB3ME Rating: 2011-12-02
great Time Owned: 6 to 12 months.
Bought this amp from HRO about 6 months ago. I live full time in an RV and have access only to 120 volt service....and most of the time not that at all. For this reason, I chose the AL-572 due to the ability to change the taps on the transformer to match my input voltage. Ran the amp as is for about 4 months (taps set at 125 V from factory) After making the mod to allow 10 meters, the amp would do about 800 to 900 watts out with my input voltage of 118. HV reading of 2600 on internal meter.
Changed tubes to Taylor 572 from RF parts a month ago, and reset the transformer taps to 115. HV now reading 2800 per manual, and output of 1000 watts (PEP SSB) consistently on 17 and 12 meters. Definitely an improvement.
80 to 15 meters performance is at 1200 watts SSB (PEP) and was with taps at 125v, no change with taps at 115, but output is at 1200+ on these bands now. Maybe the Taylor tubes made the difference, or the change in taps on transformer. I realize the 2800 minimum HV is making the biggest difference, and am pleased with the performance. I drive this amp with my Icom 7600 at the full 100 watts. All in all, I am very happy with this amp, and feel it fits my needs perfectly primarily due to the ability to easily change the transformer taps, and easily replaceable 572 tubes Good job Ameritron. This far outperforms my old SB200.
PA1ZP Rating: 2011-10-30
works but not perfect Time Owned: more than 12 months.
Bought my AL572BCXE abt 4 1/2 years ago.
Worked OK for abt a month and then a intermitted problem accured.

One of the chinese tubes would "rattle" every now and then.
Brought the AMP. back to the shop and they looked at this problem.
They couldn't find anything wrong with it.

Took it home after 2 weeks again and the problem seemed to be still there but not as often as before.

After 2.5 years had to replace the tubes , they were gone completely, and I couldn't get more as 750 watts out of them.
Also input SWR got a lot higher in time.
I replaced these chinese tubes with 4 from another chinese manufactorer.
I bought 18 tubes at once, 12 for my friends (some of them for replacing 811A tubes) and 4 for myself, 2 spares if there were any defective tubes delivered.

The coincedence was that the only defective tube from 18 new tubes had exactly the same problem as the one wich caused the problems at first hand.
A anode rattling inside the glass envelope, but these tubes do work as they should, only they make a strange noise every now and then.
And with the high voltges and powers it does not give you a comfotable feeling at all

I put 4 new tubes in the amp. and they worked FB from day one all problems were gone.

Only other problem the amp still has that it will not work OK on 10 mtrs though this version should work on 10 mtrs as it is the European export version.

I even will not bother to get the problem fixed as I rarely work on 10 mtrs and I do not need the extra power on 10 mtrs.
The first 2 1/2 years I would use the AMP daily and I abused it almost daily at full pull.
The tubes went soft but the last 2 years I only use it about 2 or 3 times a week.
And I do not use the max. power out anymore.
I have not got much time for being onair these last 2 years and the station I would work a lot went SK.
The new chinese tubes from High Hope compny work very good every time I use the AMP.

Would I buy another AL572BCXE.
NO, the problems with the 572B tubes happen to often with these amps and I would go for the AL80B now, it does not give the same amount of power but 750 watts here is more then I may and want to use.
Chances of trouble with one tube are far less then the chances of having trouble with one of 4 tubes.
The AL80B is also cheaper now as the AL572B

Chinese replacement tubes were not expencive and cheaper as one chinese 3-500, but as I said before if I had to do it again I would go for the AMP with one 3-500.

I run the AMP on 240V 50Hz as this is standard AC in my country.
The wiring from the street to my house is so thin, that all lights in my house will blink very slightly when using the AMP in CW.

The 3 is for not giving all bands and for the troubles that can occur with the tubes in this amp.
AB3ME Rating: 2011-07-20
Great Amp for the money Time Owned: 3 to 6 months.
I bought mine in April 2011 from HRO. I replaced an SB200 with this amp due to the fact I live full time in an RV Park and only have access to 120 volts to my QTH..which most of the time only runs at 118 during the winter, and down to 104 in the summer when the park is full and everyone is using their air conditioning. The SB200 worked fine if the voltage would stay up....The Ameritron with the adjustable taps solved this problem. I produces 900 watts on 10 thru 17 and a full 1200 plus on all other bands (I don't use 30M) It is easy to tune, and performs great especially with the 3 second warm up time allows chasing DX is easy. I am very happy with this amp. My only problem has been it reads only 2600V instead of the 2800V per the manual. The tech at Ameritron believes this to be due to my voltage problem, but did offer to look at it if I decided to ship it back to them as it is still under warranty. This does not seem to effect performance and per Ameritron, 800-900 watts on 10-17M is about what one should expect from this Amp. All in all I am very happy with it and would recommend it to anyone looking to get almost full legal power.
N1CKX Rating: 2011-04-06
Good Amp Once It is Fixed Time Owned: more than 12 months.
Now that the bugs are pretty much worked out, the amp is a great performer.

We measured 1340 Watts using a dummy load and a Scope.

I won’t mention where I bought the amp to protect the Innocent, but was warned to “carefully check ALL hardware and ALL solder joints. Good advice as I found a lot of loose hardware and two bad joints.

Out of the box (after rework above) it worked for about 2 hours before it began to produce a high pitch high voltage arcing sound (Like an old TV Flyback Transformer breaking down)

Turned it off and called Ameritron and they told me to check the 50 ohm resistors on the Grids, and the 3055 transistor that controls the Dynamic Bias. (This transistor dies on nearly all the Amps, More on this Further down)

This was obviously not the problem, so I removed the top cover and bypassed the interlock (Yes I know the dangers and I have worked with much Higher voltages)

Powering up the amp and tuning it produced the noise again, high voltage high frequency arc with NO excessive current on the plate. This arc was very pronounced under load, but reduced dramatically with no drive.

Turns out one of the 572B tubes had a poor connection on the graphite anode where the wire that connects to the plate cape passes through the anode. A visible arc could be seen when the tube drew current under load.

NOTE! THIS IS NOT A SHORT. This is a connection failure, and is not uncommon with graphite anode tubes. This has been reported with Svetlana tubes as well.

(By the way, research seems to indicate that Svetlana tubes, while having better Quality control, cannot handle the 2800 volts that the AL-572 amp runs, and tend to fail in a spectacular way doing a lot of damage)

I took photos of the arc, called Ameritron and the “Tech” I spoke to had no clue what I was explaining to him. I finally got him to agree to have me ship the tubes back for replacement.

Before I packed up the tubes I ordered a new set of Shuguang Tubes from a Vendor on E-Bay, which incidentally is the same tube Ameritron uses. They just clean off the name and Logo. Turns out it was a good thing I did.

The E-Bay tubes arrived in 6 days and are still working Great a Year later.

IT TOOK AMERITRON 6 WEEKS, THATS A MONTH AND A HALF, TO REPLACE MINE.

Then when the “Fully tested and Matched” Ameritron replacements arrived, I opened the boxes and noticed one of the tubes had a discolored Anode out of the box.

Plugged in the tubes, turned on the Amp, and immediately the grid current pegged negative and the plate showed about 150 milliamps of current.
The tube with the discolored anode was blushing quite red with NO drive.
Turned off the amp and put my E-Bay tubes back in and the amp ran normally.

Back to Ameritron went their “Tested and Matched” tubes with a nasty gram asking that they Actually test the next set. And I requested that they don’t take 6 weeks this time.

THREE WEEKS LATER the new set arrived. At least this set was OK. Had I waited for Ameritron I would have had a large $1700.00 paper weight for more than two months.

The Amp ran fine for another month, then suddenly began to draw 100 milliamps of plate current without drive. This time it was not a tube issue, Q3 the bias control transistor was dead.

This is such a common failure that it is the first question Ameritron asks every single time you call. (I didn’t bother calling them this time.)

I did some research on line and found some mods to replace this with a Darlington Transistor that has almost twice the voltage and Current capacity, but also requires you to put “Swamping” resistors on it to prevent it going into oscillation.

More research and I found a transistor, NTE-331, that was NOT a Darlington and had only slightly more gain and nearly double the power handling capacity. Go to the NTE web page for local dealers. Installed it with no modifications and the amp has been working great for a year without a hitch.

The Only remaining item is that the amp could use just slightly more capacitance on the Load Capacitor on 40 meters. The band selector switches in fixed capacitance in parallel with the variable capacitor depending on band.

On 40 Meters, my particular amp peaks just as the load capacitor turns through the maximum capacitance, and adding a few Pico-farads on that switch position should fix this. It’s so close that I haven’t bothered. The rest of the bands are in the middle of the Range of the variable Cap.

Final evaluation is I like the amp a lot. Easy to tune, very forgiving and great signal reports without even asking. Cheap tubes ( $140.00 Set of 4) that I could replace every year and still be dollars ahead of most other amps.

AL-800 with Eimac 3CX800A7 puts out 1250 watts (claimed) and costs $2595.00 and the replacement tube will cost you $600.00 or more. And requires at least a 3 minute warm up. (Can you say missed DX)

AL-572 with four 572B tubes puts out 1300+ (measured), costs $1795.00 and a set of replacement tubes are only $140.00. Warm up about 3 seconds.



W7DME Rating: 2011-04-01
Not good! Time Owned: 0 to 3 months.
When I look at an amplifier add that says it will do 160 to 15 meters, I expect to be able to do so without having to modify the input tuning of the amp, that is, unless the add specifically says you have to modify it in some way to get the coverage it advertises, such as the 10 meter mod required. Ameritron does not reveal this until they have your money, and then only after you discover the high SWR on the input on the WARC bands and call tech support. It is no where in the manual or advertising. If you have a broadband radio driving it and no antenna tuner, you could damage the finals in your radio. Also not in the manual is anything saying you are'nt supposed to use an antenna tuner, even though they say the amp will stand 100 watts of drive and the normal radio can't put out any more power with or without a tuner and most radios today are 100 watt radios.

Shame on you Ameritron@!
K4RYR Rating: 2010-11-27
Nice Amp.- But Caution! Time Owned: 3 to 6 months.
I have no complaints about the operation of the amp....it works great and requires very little drive to full output. However, having said that...be sure to carefully examine the internal construction of the amp. when you take off the top cover to unpack around the finals. Mine had the meters installed incorrectly in a bind and not seated properly into the front panel openings, I also found a two lug terminal strip just floating in mid air and not secured to the chassis as it should have been. MFJ supplies a lot of good products for amateur radio and we are lucky to have them in the USA, but the quality control leaves a lot to be desired, so always carefully inspect anything you buy for mfg. problems.
AA6QQ Rating: 2010-11-05
Oldie but a goodie Time Owned: 6 to 12 months.
It was born in the fall of '97, serial number 00024, the original owner bought it from AES in '98 and had it for eleven years, he replaced it with the Yaesu Quadra, I purchased it from him last year for about .50 cents a watt, he told me he didn't use the amp much and pretty much only on 15 and 12 meters. It puts out a little over a kw on 110v with the original Svetlana tubes. I did a lot of research... probably too much and was going to wait until I could afford something solid state because I thought it would be a hassle to tune a tube amp. I had read that Ameritron amps were more MFJ junk and you had to buy a used one that had all the bugs worked out to get a good one. Then a friend told me about this little gem that was for sale.

After watching how to tune a tube amp on YouTube, reading the manual and going to the Ameritron web site I gave it a try. I was pleasantly surprised how easy it is to tune and how consistent it is. I have a "cheat sheet" with the settings for each band, dial in the numbers and then fine tune for that freq. I'm amazed how tuff this guy is from all the times I over drove it with my 200 watt Yaesu MK V, had the band switch on the wrong band and countless other mistakes. The only problem I had with it was one day one of the tubes didn't light up, I called Ameritron, great service by the way, I have never waited more than about 20 seconds for a tech, after talking to Richard I wiggled the tube back and forth and it lit up.

I'm glad I didn't wait and bought this when I did, I should probably get a set of matched Taylor's some day and I will, but for now the original one's are working just fine. I suggest purchasing the plastic allen wrench from Ameritron and tuning all the bands from the holes in the back. Yes sir, it's solid as a rock, if you can find one locally from a good ham, snap it up. I wouldn't buy one on eBay, you never know what has been butchered up for eleven meters.

To sum it up it's a great near legal limit amp that runs on house current, runs cool, is rugged and the fan isn't much louder than my computer's

73's

Roy AA6QQ
N2JXN Rating: 2010-07-11
great so faf Time Owned: 0 to 3 months.
Nice amp get rated output. Only problem was when I did the 240 volt conversion. Powered up the amp and R27 as shown on the circuit board 127 as shown on the schematic smoked. Replaced it with an equal and since no Problems. From what I understand this is normal for MFJ. Contacted Ameritron and they sent me a replacment under warranty