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Reviews For: Ameritron AL-811H

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

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Review Summary For : Ameritron AL-811H
Reviews: 187MSRP: 899
Description:
160-10 meter RF Amplifier. 4 811A tubes
Product is in production
More Info: http://www.ameritron.com/Product.php?productid=AL-811H
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
34.31874.5
WA3SIMI Rating: 2005-11-21
Good value! Time Owned: more than 12 months.
Lightweight and quiet desktop linear amp.

I have transmitted into high SWR's that arc'd my tuner, but the amp keeps going.

It's 800W pep, but only 600w CW, and 350 W AM.

I have to use the FM mode on my radio to get the steady 70 watts needed to tune it properly. You can then reduce the drive. The LOAD control doesn't respond accurately until you have enough RF drive.
WA0ZZG Rating: 2005-09-21
Grounded Grid problems Time Owned: more than 12 months.
I owned this amp a couple yours ago and had to
get rid of it when I moved to a condo. Nice basic
design, but shares most of the problems that go
with a grounded grid design. Cathode drive places
the RF input and output in series. There's also
a LOT of RF ground currents in the chassis. There's no problem as long as there is no ground
resistance. Any time I see a GG amp get 'funky',
the first thing I do is re-snug every chassis screw and nut in it.
Also, this design runs 811A's at their limit. If
the operator doesn't follow the tune-up
instructions, excessive RF voltage will appear on
the plates, combine with the DC voltage and exceed
the breakdown limit. This causes an arc to the
grid, burns out the 50 ohm grid resistor which
cuts off the tube. This resistor is a standard
carbon comp, don't use any other, but is buried
under the socket mounting plate. What's really
strange is that these amps will make nearly full
power with just three tubes operating. A common
symtom heard is someone saying they heard a pop,
then back to normal operation. It's not uncommon
to find only three tubes discoloring when driven
to full output.
It's a good basic design, but needs a little
maintenance.
Dave...
REMOVED_KH7M Rating: 2005-09-21
Arc problems Time Owned: 0 to 3 months.
Aloha gang, bought a several year old 811H from
a fellow out here who used it almost not at all.
He bought it in the very early 90's. I have
had it about 7 weeks now, used daily. But
one day last week, turned it ON, and BAM
-- BAM....startled the heck out of me!

Shut it off. Next day, turned it on again, and
worked just fine on 40 meters. Next day, turned
it on again, and Bap, brief sound, a flash and
it went dark! Both fuses blown.

Called Rich Measures, as others have suggested below.

He said the amp is liable to break into a bad
95 MHz parasitic at any time. That was probably
what I experienced; Measures suggested that
now I might have a short between filaments
to ground somehow, thus the blowing of fuses.
This from a huge flow of grid current caused
by the parasitic; that current had to comed
from the filaments which would then be damaged.
Sounds reasonable to me.

So, I ordered one of his kits, which should
get out here late next week.

Will check the tubes, hope they are still good,
and install the suppressor kits. Trust I don't
have to order new tubes also. Will advise
in two or three weeks the outcome. 73, Jim W6KPI/KH6
NG1I Rating: 2005-08-09
No Problrms At All Time Owned: 6 to 12 months.
It is interesting to see the other posts..I'm sure the tech trouble calls to them made them improve the amp's dependibility.

I love mine and has no problems of any kind....besides 500-600 watts is all any would need IF they had to use it.

NG1I
http://webpages.charter.net/maclamb
WD0CT Rating: 2005-07-24
just okay Time Owned: 3 to 6 months.
I bought this amp used and didn't own it very long. I can't remember if it had any parasitic problems but it did take out a grid resistor once.

The amp had good power and was light and easy to operate.
KI4DTB Rating: 2005-06-13
Good rig, can have parasite problems Time Owned: 0 to 3 months.
Bought an older mod. 811H, and had an identical experience to N8GNI (page 1 reviews). Rig kept arcing and burning out grid resistors. This happened three times in a row. With interspersed calls to Ameritron, I sequentially replaced: grid resistors, plate suppressor circuit and grid r's, grid r's and tubes. Finally there was nothing left to replace and rig was still arcing. Ameritron insisted my new tubes were also bad. Then I read N8GNI's review, and ordered and installed Mr. Measures retro-fit suppressor kit. No more arcs. Rig works fine with both new and old tubes. I talked on phone with Mr. Measures twice, and he was extreemly cordial and helpful (also a pleasent guy). If you should have the above problem, visit His web site (http://www.somis.org/), read it, then decide what to do BEFORE you buy new tubes or parts.
K4GHS Rating: 2005-05-02
Good amplifier for the money Time Owned: 0 to 3 months.
I've had the Al-811H for about a month now and am really very pleased with it. No problem setting it up and it performs well on all bands. Never used an amp during my 50 yrs of hamming until now and it has made a big difference in my signal. Would recommend it to anyone, especially those who have never used one before. Am interested in seeing how long the tubes will last.
KM3X Rating: 2005-04-24
very good amp Time Owned: more than 12 months.
I've had my Ameritron AL-811H over a year and has never given me any trouble. It's a great package for the price and really does give you the extra punch in poor band conditions. It's also a good starter amp for the new HF operator.

73 - Brian
KF3EG Rating: 2005-04-13
works for me Time Owned: 3 to 6 months.
Works well, no problems, full output on every band.
Never had to touch the tuning slugs for the inputs, swr was 1.3 to 1 or lower on every band.

would be nice to have a built in watt meter, but hey for the money, I can look at the one in my tuner.

73 Jim
KW4J Rating: 2005-04-12
Great amp and inexpensive! Time Owned: more than 12 months.
I bought mine several years ago and it has been problem free. I have used it with several differnet rigs and with/without the QSK-5 switching unit. I usually let it loaf at around 400 watts, but I have tested it at 800 with success. It works well with all modes,including the ones with long duty cycles such as RTTY.