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Reviews For: Ameritron AL-80A

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

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Review Summary For : Ameritron AL-80A
Reviews: 56MSRP: 1399
Description:
Ameritron AL-80a 1KW Output, 160-15, 10 possible with mod.
run a single 3-500z, 850 watts CW, 1000 watts SSB.
Product is in production
More Info: http://
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
00564.9
N4RAP Rating: 2005-08-02
Wonderful!! Time Owned: more than 12 months.
I have had this amplifier for about 8 years. Other than burning out two 3-500Z's I have had no problems. I use it on 17, 20, 40, 80 and 160 meters. I use it every day and run it to the "max" everytime I turn it on. It works great and is very quiet. Well thoght ou and well planned. Knobs feel good and look good. I bought this thing at a hamfest for $600.00 and it has been quite a bargain. Love it and highly recommend it.

N4RAP
K0WA Rating: 2005-07-01
Good Standard Amp Time Owned: more than 12 months.
I like this amp because it is very simple and with a little carefull tuning gives wonderfull service. I have owned the amp for over 5 years and have found the amp to work well without fault. It is a very standard design with common parts. I have yet to burn up a band switch. It is very forgiving and will make a good 500 watt out on 10 meters and 700 on 80/160 meters. I have had no trouble with this amplifier. For a smaller type of amp...it is pretty good.
W9DJ Rating: 2003-06-10
Great Bang for Buck Time Owned: more than 12 months.
I've owned an AL-80A since 1990. I have the same tube, and it's never been repaired except for cleaning the T/R relay once in a while. I usually run it at about 700 watts out indicated, although on some bands it will only put out 500 or so. I try to keep the plate current at about 400 ma, and the grid current at around 150 ma. No bangs, pops, or other weirdness. It, like most things, likes to see a good match. I run it on 120 vac. Yes, I'd probably like an Alpha more, but this one is just fine.
KE5UT Rating: 2003-04-27
Good Amplifier Time Owned: 6 to 12 months.
I have an AL-80A for little more than 6 months now. It is in pristine condition with an original EIMAC in it with low hours. Easy to tune, predictable to re-tune. About 1100 watts out max within grid and plate current ratings, as measured by a Bird on 80-20 meters, 950 watts out on 15 meters, and 850 watts on 10 meters, all with about 75 watts of drive, although I seldom push it that hard on any of the bands. The fan is quiet. Nothing fancy - no QSK - but it does have current inrush protection, and a forgiving, single 3-500Z. For what it is, I am pleased with this amplifier.
KB0FHP Rating: 2002-10-05
Excellent Time Owned: 0 to 3 months.
Bought an AL-80A amp on Ebay, and paid less then what I would pay for most amps used. I met the gentleman and picked up the amp, so I wouldn't have to deal with shipping. After dealing with putting in a new 220VAC line for the amp, and hoking it up, I have been well pleased. It is quiet, and turns my vertical from a dummy load to at least somewhat competitive. Amp loads well, and puts out 1K all the time from 60-70 watts. Well worth getting. Now if I can just figure out how to get a tower in my small yard.....
N0SP Rating: 2001-05-12
A great amp AFTER you solve a few problems with the design. Time Owned: 0 to 3 months.
I recently had the opportunity to purchase an AL-80A for eventual sale to
another ham friend of mine. One thing that was troubling began happening
right away.. approx. 2 or 3 times in a few hours of operating. At various
times while transmitting a loud firecracker-like "BANG" would go off in the
amp. At first I thought it was an arc in the plate capacitor. Several
inspections and cleaning sessions yielded no relief. Then I happened to be
looking at the amp once when it blew. The grid current meter slammed so
hard against the pin I thought it would bend.. THAT was the clue. This was
a powerful VHF parasitic causing the trouble. So I re-designed the stock
parasitic suppressor with a design that Richard, AG6K, has talked about in
some QST articles and his website. He also sells a kit to fix the problem..
very inexpensive, something like $7 or $17.. can't remember, but WELL worth
it. After the installation of the new parasitic suppressor there has not
been a single "pop" in some 20 or 30 hours of operating.
Let me mention some other pitfalls one is likely to experience with
this amp if they follow the manufacturer's instructions... It troubles me
that the manual from Ameritron (really MFJ) tells the operator to tune up
the amp to a condition that substantially exceeds the ratings on the 3-500Z
tube! These tubes, when operated according to Eimac specs, should give 20
years and thousands of hours of service. This will NOT be the case if you
tune it up like MFJ tells you to. MFJ says to load it up to 550 mils plate
current yielding about 1000 watts out. The Eimac data sheet for the 3-500Z
clearly places the maximum rating at 400 mils. Also, when tuned to this
excessive condition the grid current will exceed the limit and you will be
driving the tube out of linearity. The real way to operate this amp would
be to increase drive power to the level where the plate current dip is at
400 mils. This is around 65 watts from the exciter if the 3-500Z is healthy. Then limit your
absolute voice peaks to the 65 watt level. This will produce about 750
watts peak output, long life of the tube, and clean operation. A
peak-reading wattmeter is very helpful. These numbers assume approx. 3,100
volt on the plate and 220 volt operation. I recommend using 220 if
possible. The high voltage regulation is a bit better.
One other thing you might check is filament voltage applied to the tube.
With the cover off the amp attach two probes to the filament contacts on the
socket and use a good DVM to read the A.C. voltage. It should be 4.8 volts.
If it is much higher, over about 5 volts, you'll experience substantial
reduction in the life of the tube. A 3 to 5% increase will shorten the tube
life by roughly half. This amp was at 5.0 volts. I'm adding a few inches
of smallish wire in the filament circuit to introduce some added resistance
to reduce it a bit. But some operators have found much higher heater
voltage in their amps. With 5.1 or higher I would fix this without delay.
One note.. BE CAREFUL when reading filament voltage. Use an alligator clip
to attach the leads and read it remotely. DO NOT attempt to hold the leads
by hand. You're very close to the high voltage lead if you do. You will
have to defeat the cover safety switch to make the measurement.
With these things in mind the amp will give good service for many years.
I have a Heathkit SB-1000 which is the same design. I've had it 12 years
with the original tube. It shows no signs of stress or discoloration. The
very useful information on AG6K's website shows how to correct these
problems in linear amplifiers. These were incorporated in my SB-1000 when I
first got it and it has been trouble-free ever since. His website is:
http://www.vcnet.com/measures/
These amps are a good investment and provide output only 3db below the
maximum legal limit with about 8db less dollars than the big amps. You
should be able to find a used one in good condition in the $500 range.
They're easy to work on... just ignore the operating instructions and apply
the limits Eimac recommends and you'll be happy with it.
One note.. using a new 600 watt variant of the 3-500Z that is being
offered by some is NOT a solution to the excessive rating problems. This
new tube may last a bit longer at the 550 mil tuning conditon but you will
still be operating out of linearity. Other operating paramaters have to be
changed to preserve clean output. Simply increasing the plate current does
not get it done. An amplifier re-design would be necessary.
73 and have fun with the amp... after you make the changes!
Dennis
NØSP