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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Ameritron AL-572B Help

Reviews Summary for Ameritron AL-572B
Ameritron AL-572B Reviews: 56 Average rating: 4.0/5 MSRP: $1400
Description: Four Svetlana Russian 572B tubes give near legal limit power.
Product is in production.
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KD6RSQ Rating: 5/5 Jul 15, 2015 19:05 Send this review to a friend
great amp  Time owned: 0 to 3 months
I bought mine used (15 years old) with taylor tubes and it works great. The reviews I see that are negative it seems to be bad import tubes. I love mine
KE7BJQ Rating: 4/5 Aug 25, 2014 13:22 Send this review to a friend
Good with Caveats  Time owned: more than 12 months
The AL-572 was purchased at HRO. Got it home and unpacked it. The foam around the amplifier was in place. I opened it up to install the tubes. The tubes were already installed and no packing material. I guess a convenience provided by HRO. Checked as many of the solder joints as I could which is usually a problem with MFJ. Didn't find any cold ones but didn't completely take it apart. According to the manual it will produce full rated output on 115 volts AC. Something about the winding of the transformer. Read through the manual several times before powering it on. Decided to try it on 20m. There was a Croatian station calling cq with quite a pile-up. Tried four times with 100 watts and no joy. Turned on the amplifier. Everything lit up including the tubes. Started tuning up into my oil can. About half way thru the procedure I encountered the curse of the Chinese tube. There was a loud pop. immediately put amp in standby and looked into the tube area thru the side vent. Three glowing tubes. One not. At this point I was wondering about other damage to the amp. I decided to test it. I continued the tune up process. Ended up with about 850 watts out. Worked the Croatian station with a 59 report. For several months I have been trying to find a replacement tube. One company has not had them due to trying to establish another Chinese factory. I guess we will have to get used to Chinese tubes. After having had an AL-811 this amp is much better. But I don't like the Chinese tubes and the scarcity of 572 tubes. I think my next amp will be solid state. Better technology there at the same price. Also the transistors are easier to obtain.
K5AX Rating: 4/5 Apr 22, 2013 12:51 Send this review to a friend
Good Amp  Time owned: 3 to 6 months
Only problems I have encountered were caused by crappy Chinese tubes. Currently all my tubes are good, and the amp is working perfectly. 900W on 10M, 1100W on 15M etc. Actually a nice unit.
W1RMS Rating: 5/5 May 7, 2012 00:54 Send this review to a friend
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.


Roger W1RMS
PA1ZP Rating: 3/5 Oct 30, 2011 11:28 Send this review to a friend
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: 5/5 Jul 20, 2011 18:58 Send this review to a friend
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: 4/5 Apr 6, 2011 18:27 Send this review to a friend
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.


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.

AA6QQ Rating: 5/5 Nov 5, 2010 04:53 Send this review to a friend
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


KB8E Rating: 4/5 May 6, 2009 08:21 Send this review to a friend
No Issues  Time owned: more than 12 months
I purchased this amplifier 9 years ago with the Svetlana tubes installed. No real issues. Tunes up nice and makes 1 kW+ with 50 watts drive. Works best from a dedicated 220-volt line, no flickering lights, voltage sags, etc. Also, tapped primary to reduce HV to 2500 VDC no-load. No change in performance and the next set of tubes (if there ever is any) should appreciate it. Installed QSK-5PC kit and it works well. Recommended, only reason for not a 5 is that good 572B tubes are apprently hard to come by now.
W3NRL Rating: 5/5 Feb 10, 2009 20:22 Send this review to a friend
Sweet  Time owned: 0 to 3 months
I traded for this unit and sent the unit to Ameritron for just going over and getting a clean bill of heath, also managed to get 4 Taylor 572b's and wala and sweet!!!!
I recommend this amp
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