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Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Ameritron AL800H Help


Reviews Summary for Ameritron AL800H
Ameritron AL800H Reviews: 12 Average rating: 4.5/5 MSRP: $2,599.
Description: Two 3CX800A7 - 1500 watts plus
Product is in production.
More info: http://www.ameritron.com/
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N5GOD Rating: 5/5 Dec 21, 2013 11:16 Send this review to a friend
Great Amp  Time owned: more than 12 months
I really like the AL800H amp. I bought mine used and has big power in a small desktop package. It will get the job done. Yes there are some negatives such as price of tubes and the loud fan, I can work around the fan putting it in quarantine..HI HI...but overall it is a great amp without a huge price tag.
 
K9BF Rating: 5/5 Aug 12, 2011 13:55 Send this review to a friend
Great amplifier, But  Time owned: more than 12 months
I have been using my AL-800H for years now. I really like it but the cost of a new pair of Eimac 3CX800A7 is nuts. I just checked with RF parts and they want $899 each or $1800 for a pair. I called Penta tubes and they will sell me a new pair for $990. Next time it will be a solid state amp for me.
 
VR2AAW Rating: 5/5 Oct 28, 2008 10:03 Send this review to a friend
Powerful Amplifier  Time owned: 0 to 3 months
I use this amp for two months, feeling good, IN the 20m, I give 20w in can out 1kw & 60w input output of any kind easy 2kw, due to the antenna can only be by the end of 2kw, I can only test to 2kw. al-800h the use of two 3cx-800a7 tube, power should be able to reach 2.5kw, waiting for the future 3kw dummyload, will be tested,I like being back in this amplifier
 
WD0CT Rating: 4/5 Jul 24, 2005 01:31 Send this review to a friend
decent amp  Time owned: 3 to 6 months
Lots of power in a very light package. Fan is just plain loud.

Mine had the optional qsk board. The fuse bulbs gave me a bit of trouble until I got everything sorted out with it. But having these cheap fuse bulbs is a good idea.

It took out a meter protection diode on a board once when it had a big bang - high voltage arc. The tubes survived as did everything but a 5 cent diode.

Ameritron service guys helped me out on the phone and were good to deal with.

This amp is not a brick on the key legal limit type but as a phone ragchewer I didn't care. It is no heavier than a SB 220 but has much more oomph available.

The fan could be quited down without much work.
 
N4DEK Rating: 5/5 Jan 25, 2005 16:05 Send this review to a friend
Great amp for the $$  Time owned: 0 to 3 months
This is my second AL-800H and I am well pleased with it. Alot of watts for the dollar here. It may not be built like an Alpha but it gets the job done all the same. And for alot less money. Mine runs 1500 out with about 30 in so its still just loafing at legal limit. I did have an issue with the Dynamic Bias on SSB but that problem has been cured via phone with Ameritron's tech dept. Customer service is first rate with this company as well.
 
K8AC Rating: 4/5 Feb 9, 2003 16:37 Send this review to a friend
Good value in the "used" market  Time owned: 0 to 3 months
I recently acquired my AL-800H on eBay for a good price, but with a known problem. Of course, the one problem turned into several and it took a couple of weeks to get things going again. I'll address my comments to dealing with a second-hand AL-800H.

As others have mentioned, the blower on the amplifier is a bit on the loud side and I decided to see what could be done to quiet things down a bit. Someone referred me to the article by Bob Hutchinson, N5CNN, that addressed this very problem. Bob's approach was to use a temperature sensing switch mounted in the tube cooling airstream, slowing down the blower when the airstream temperature drops below 110 degrees F. This is accomplished by switching a fixed resistor in series with the blower motor, and the basic design includes a pot to allow you to set the "high" speed to full, or a slower speed. Here's the URL to Bob's article:
http://www.hamradiomarket.com/Articles/Quieting%20The%20Blower.htm

The article is well illustrated, and I was able to obtain the parts from Nebraska Surplus Sales and W. W. Grainger as recommended. Be aware that Grainger sells only wholesale to other businesses, but I was able to buy the switch over the counter at the local Grainger supply house. Now when the amp is just idling, the blower speed cuts back quite a bit and I can live with the level of noise. I think much of the remaining noise is caused by the mounting arrangement of the blower - it's screwed securely to the rather thin center vertical panel in the amp and that tends to amplify the mechanical noise. One of these days I'm going to attack that problem by using a cork or rubber gasket between the fan and the panel, and using some sort of rubber bushing to isolate the screws from the blower housing a bit.

The second problem I found was the 80 meter tank coil was toasted as some others have mentioned. There was no glue in that area, but the plastic rods that support the coil turns had apparently softened from high heat, allowing the turns to collapse under their own weight and a couple of turns were shorted together. You can buy a new coil from Ameritron for around $54, already prepared to solder in place. I elected to buy the uncut coil stock from them for $35, and see if I couldn't improve on the arrangement. Whereas the original coil had been prepared by removing an entire turn where the 160 and 80 meter coils meet, I cut the coil at that point on the bottom, using a Dremel tool and pushing in the adjacent turns a bit so I could get the cutoff wheel on the desired turn. The result is a more rigid coil structure.

The next problem was that I couldn't get full output on 40 meters, and the the output power drifted downward within a second or so of applying drive. I went into the final tank compartment and heated all the connections to the 40 meter tank coil with my 140 watt gun. The construction there really isn't very solid and the tank coil ends simply pass through the circuit board and are soldered. After reflowing the solder at those points and on the bandswitch, the 40 meter problem was gone.

Next came the grid/plate meter bulb, which had burned out. No replacement was listed in the Ameritron parts list, but a trip to Radio Shack turned up a nearly perfect replacement. Their part number 272-1141 is the exact same size and mounts perfectly in the plastic holder. I painted the bulb white with an artist's brush and white latex house paint and the result almost matches the other meter illumination in intensity and color. Without the white paint, the new bulb was too bright (the original Ameritron bulb was also painted white).

Next I checked the diode, D117, since the manual warned of the possible failure of that component. Mine was bad and I replaced it with a new 1N4001. Don't use a higher PIV diode here - the PIV rating of the 1N4001 is used to force a diode failure under some conditions.

The last problem was the worst and pointed out an unpleasant characteristic of the AL-800H. Neither the forward nor SWR meters on my amp registered anything and upon inspection I found that the toroid was shattered from overheating, the leads had been pulled out, and several associated parts had been toasted. While it first appeared that I could replace everything from the top of the board, that turned out not to be the case and I ended up having to unbolt the transformer and unsolder many wires that connected to the board in order to hinge it up so I could get to the bottom side. Definitely NOT a maintenance friendly design. If you ever have to get to the underside of the board, I highly recommend taking many photographs so you can refer to them during the reassembly phase. I had to order a new toroid from Ameritron, and they came through with that and a few other parts in short order. However, they refused to tell me how to adjust the wattmeter circuit saying that it wouldn't be necessary. That was not true, of course, and I had to get the info elsewhere. I also had to call them back for a simple capacitor which just wasn't available locally. Although they promised to send it right out, it never did arrive. The toroid they sent me was pre-wound and I installed it exactly as the old one was mounted. But, the new toroid was wound in the opposite direction and the forward/reflected power meter functions were reversed. Reversing the toroid leads solved that one.

After all this, the AL-800H works as it should and never complains (no arcing, etc.). Based on what I saw in the tank coil and the power sensing circuit, I'd say that it's probably not a good idea to run this amp at full power on RTTY or SSTV on the lower bands if your SWR isn't just about unity. While Ameritron at first appeared to be very helpful, their technician clearly didn't know as much as I did about the amp and they didn't always carry through on their promises of delivering parts. The parts I did purchase from them were priced fairly.

Much to my surprise, the 800H cabinet size is the same as the AL-80B I have. The input matching coil box is mounted outside the rear panel on the 800H to make room for the tubes. I don't know of any other 1500W amps that are so compact. If you're going to buy one of these used, I'd sure that everything works as it should and inspect the tank coils for damage. It's hard to understand how the previous owner lived with these problems!
 
W7DZN Rating: 4/5 Dec 13, 2002 15:26 Send this review to a friend
Great amp but loud fan  Time owned: 0 to 3 months
I bought a ~6 year old AL-800H with original tubes. It sure looks like it had gotten some use but it still easily puts out 1.5KW CW on 80 through 10 meters with between 50 and 70W of drive. It also has the QSK-5 option which works very well for full QSK CW.

Initial tune up can be touchy because of the sensitive grid current protection circuit (this is a good thing) but if you properly hook up and use the adjustable ALC, the ALC will cut back the exciter power to protect the grids instead of tripping the protection. This makes tuning very easy. For a detailed discussion see:

http://www.hamradiomarket.com/Articles/ALC%20for%20real.htm

The Plate and Load controls are nice smooth verniers and once you have the tuning worked out, you simply need to set the numbers on the dials when you change bands. No further peaking is required.

The QST review of this amp showed it to have one of the best two-tone IMD specs of any of the amps they tested.

The fly in the ointment is its loud fan. I mean really loud... unacceptably loud. I built a wooden, foam-lined enclosure, which seals around the front of the amp with a gasket. The back of the enclosure is open and has a duct to direct the hot exhaust air from the tubes out the upper back right hand corner while intake air is drawn around the top, bottom, and left side of the amp. It made a huge reduction in the noise level ...down to about the same as the fan in my exciter, and the amp stays nice and cool. My antenna tuner and power/SWR meter fit nicely on top of the enclosure.

This is a nice, compact, lega-limit amp and considering the price and performance, I wanted to give it a 5 but had to give it a 4 because of the loud fan.

Lou W7DZN
 
K1ZYW Rating: 5/5 Mar 20, 2002 08:07 Send this review to a friend
Great amp  Time owned: 0 to 3 months
Years ago I built an amp w/ four 811 tubes. It took up a six foot rack panel. Lasted over 20 years till I gave it away.

This Ameritron AL800h is the amp I wish I could have built. Small, light, quit, attractive, effecient on 110v. The stock tubes are not the best. Dont push every last watt out of it. Replace later when the stock tubes die with better 811's or if the wallet allows 572b's.

I worked all continents in 10 minutes on 20 meters the first day with this amp and a GAP vertical! Hummm. Best bang for the buck

If money is an issue and you want an amp - buy it.

73's
DE ken k1zyw
 
KS9Y Rating: 4/5 Jan 15, 2001 16:44 Send this review to a friend
They'll hear you with this amplifier.  Time owned: 0 to 3 months
This amplifier takes up a small space on my desk, but puts out the full legal limit with drive power between 50 and 65 watts. It just loafs along doing 1 KW. I've been able to work several pile-ups with ease. I've also had several DX stations tell me that I was the loudest signal on the band in Europe and Australia. It is an easy amp to tune up with definite dips on the plate current and increase in rf power when you hit resonance. By savings the settings you can go from band to band with ease.
Somethings I don't like about the amp are blower noise and the three minute wait for warm-up of the the tubes. Three minutes can seem like an eternity when you're waiting to work a rare one. I'm becoming more used to the fan noise, but it really can be a distraction.
This amp is definitely a keeper.
 
KE4WY Rating: 5/5 Nov 21, 2000 02:45 Send this review to a friend
Good Legal Limit Amp with small footprint  Time owned: more than 12 months
The AL-800H is a legal limit amp with a small footprint. It's about the same size as the popular AL-80B single 3-500z Amp but the AL-800H has two 3cx800a7's and easily puts out 1500 watts power.

For a small package, the AL-800H performs very well.

As mentioned in an earlier post Ameritron's grid protection circuit helps make the amp idiot proof. The protection circuit works very well.
Once I was use to tuning the amp (After the first day)and wrote down the approximate PLATE and LOAD settings for each band that I keep on a small tuning sheet I never see enough grid current to kick the protect circuit while tuning. I tune with a pulsing tone that is easier on the tubes than a steady carrier. It takes me just a few seconds to tune each band. In fact I now have the plate and load controls memorised and do not have to refer to the sheet.

The amplifier handles full 1500 watts output with ease during round tables on 20, 40 and 75 phone with the exhaust not getting too warm. With 45 - 60 watts of drive I am able to get 1500 watts out of the amp. I did not feel the cooling fan is too noisy. I have owned amp's with louder blowers or fans and amps with quieter fans......this amps cooling system appears to fall in the middle concerning noise. Again quite acceptable to me.

In an earlier post by another Ham a concern was mentioned concerning the 80-160 meter coil and melting glue. I thought I would just take a look at mine and noticed it is intact with no signs of heat problems at all nor do I see any glue???

One nice thing, the cross needle wattmeter does in fact appear to be peak. Nice for phone.

For the money I feel this amp is a good bang for the buck with a grid protection circuit that appears to work well. It's a good medium duty legal limit amp at a good price with a small footprint that doesn't dominate the shelf.

I would buy another.

73 de KE4WY Jim

 
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