Call Search
     

New to Ham Radio?
My Profile

Community
Articles
Forums
News
Reviews
Friends Remembered
Strays
Survey Question

Operating
Contesting
DX Cluster Spots
Propagation

Resources
Calendar
Classifieds
Ham Exams
Ham Links
List Archives
News Articles
Product Reviews
QSL Managers

Site Info
eHam Help (FAQ)
Support the site
The eHam Team
Advertising Info
Vision Statement
About eHam.net

   Home   Help Search  
Pages: Prev 1 [2]   Go Down
  Print  
Author Topic: AL-811HD - Three Questions  (Read 4467 times)
KE3WD
Member

Posts: 5694




Ignore
« Reply #15 on: December 28, 2012, 03:37:52 PM »


Ah... but were those 811 tubes the current "Made in China" version?


And a Soft Start circuit is supposed to correct problems with badly manufactured tubes? 


73
Logged
W6JHB
Member

Posts: 21


WWW

Ignore
« Reply #16 on: December 28, 2012, 07:14:33 PM »

Guys - thanks for the many comments! After "discussions" with the XYL and reviewing the bank account, I took the low road and ordered a plain old AL-811 from DX Engineering. Yes, I'd love to have that AL-80B (or an Alpha for that matter), but household harmony wins out.  Wink

Oh yeah, had to get an RF watt meter to go behind the amp, so that just added more to the total. Arrghhhhh....!

Thanks again, 73 - Jim
Logged

Jim / W6JHB
Retired in Folsom, CA - and loving it!!!
WB2WIK
Member

Posts: 20540




Ignore
« Reply #17 on: December 28, 2012, 07:28:46 PM »

Guys - thanks for the many comments! After "discussions" with the XYL and reviewing the bank account, I took the low road and ordered a plain old AL-811 from DX Engineering. Yes, I'd love to have that AL-80B (or an Alpha for that matter), but household harmony wins out.  Wink

Oh yeah, had to get an RF watt meter to go behind the amp, so that just added more to the total. Arrghhhhh....!

Thanks again, 73 - Jim

You just discovered why the AL-80B is actually a better deal.

Newer tube, much more powerful; larger power supply; built-in "inrush currect protector" (soft-start circuit, part of the base design); built-in PEP wattmeter/SWR bridge; and even an RF-actuated biasing system which reduces TX standby current to zero, saving some heat and electric power.

I have no clue why anyone buys the AL-811, when by the time you add these features, it costs as much as an AL-80B and still only runs about 60% of the power.
Logged
KE3WD
Member

Posts: 5694




Ignore
« Reply #18 on: December 28, 2012, 07:53:46 PM »

Congrats on the new gear, Jim.  You should be able to get a lot of use and FUN out of it. 

And that's really what its all supposed to be about. 

"Don't let anybody steal your joy!" 

Enjoy,

es 73
Logged
N7WR
Member

Posts: 31


WWW

Ignore
« Reply #19 on: December 29, 2012, 09:00:38 AM »

Having owned a LOT of amps over the years I agree with those who suggest the AL 80 (A or B).  Run it on a dedicated 120VAC circuit and you will be fine.  I currently use an AL 811H with 811 tubes, run on a dedicated 120VAC circuit and never run at more than 550 watts.  Works great.  No real advantage to 572B's over 811's.  In fact the quality of 811's is better than the 572B's currently available.  No need for an amp interface either.

If you need to re-tube an 811 amp I suggest RF Parts.  If a tube goes soft during the warranty period they are great on providing a replacement under warranty. Finally, the 10/12 meter mod is simple.  Info on which wire to cut (already suggested by another) as well as photos depicting exactly which wire are available on line.
Logged
WX7G
Member

Posts: 5908




Ignore
« Reply #20 on: December 29, 2012, 09:07:53 AM »

Jim,

you will have fun with your AL-811. Where are you ordering it from?
Logged
W6JHB
Member

Posts: 21


WWW

Ignore
« Reply #21 on: December 29, 2012, 10:35:45 AM »

The order was placed on Friday afternoon with DX Engineering in Ohio. Shipping is less than $13 and NO sales tax, so that saves me about $60 initially. I did look at RF Parts and see they have matching sets of 811A and 572B tubes offered. So, if the 811A's crap out I can see about getting replacements there. Hopefully it'll be a while before I need to do so.

My initial plans are to run the AL-811 on a 117V line in the shack and see how it works. My K3 is solar / battery powered using three 120 aH AGM batteries in the shack, so there will be no 117V load from the K3. The AL-811 will pretty much be on it's own 117 circuit, so it might do OK there. We'll see.

Jim,

you will have fun with your AL-811. Where are you ordering it from?
Logged

Jim / W6JHB
Retired in Folsom, CA - and loving it!!!
K4RVN
Member

Posts: 757




Ignore
« Reply #22 on: December 29, 2012, 11:25:58 AM »

Jim,
I have owned my three tube AL 811 for 3.5 years now so can give you some advice that you can consider if so inclined. When you remove the cover to take the packing from your tubes, make sure all the screws are  in the sockects especially the ones grounding the grids. Also check the entire amp for missing screws and extra screws and nuts lying around the amp. Look it over really well including all the wires for any missed solder joints or splatters.
My tube socket was missing a screw and nut which grounded the grid and the antenna connection had no screws and fell inside when I was connecting the antenna. Despite these minor faults I love the little amp and have had no problems since the initial inspection. Also, tune it with a watt meter and take it easy on the tubes by running about 400 to 500 watts for a time. My 811As are still doing great and I now run it about 500 to 550 watts most of the time. It gets great reports connected to an Icom 7200. You don't need any extra parts, etc. for ten and 12 meters. A simple mod. can be had by sending the place you bought it a copy of your license by email if required. Learn to tune the amp quickly using the presets in the manual as a starting point. This is the lowest priced amp for the watts I have found and that's why so many newbies to amps abuse them and blow tubes, etc. That is not to say that some of the tubes are indeed faulty to begin with. I also have the AL 80A with the 3-500 tube which is a better amp but cost almost twice as much. The soft start is not neeeded in this amp and 120 volts with #12 wire should do fine for a good stiff supply. Also 572 tubes won't give you any more output but they are more rugged and stand more tuning abuse if you happen to get a good set on the initial purchase.
I would suggest copying the page from the manual several times to allow you to keep a copy of the presets for your own antenna to cover each band. Ameritron has the page in the manual for your convenience. Its a great little amp and good luck to you. Also Happy New Year.

Frank
Logged
W8JX
Member

Posts: 5358




Ignore
« Reply #23 on: December 29, 2012, 12:25:13 PM »

Also 572 tubes won't give you any more output but they are more rugged and stand more tuning abuse if you happen to get a good set on the initial purchase.

Basically true if you run the 572's at 811 drive plate current levels. Given that you could run higher plate current on 3 tube unit and safely run 600+ma total on 572's (which you could run on 4 811's) and get higher output levels.  Since both amps use same power supply this is possibly. On 4 tube 811 amp there is no power left so you will not be able to push 4  572's harder like possible in 3 tube unit. That being said nothing really gained with 4 tube amp using 572's because of power supply limitation but in a 3 tube it could be viable.   
Logged

--------------------------------------
Entered using a  WiFi Win 8.1 RT tablet or a Android tablet using 4G/LTE or WiFi.
W6JHB
Member

Posts: 21


WWW

Ignore
« Reply #24 on: December 29, 2012, 03:05:09 PM »

Great info and comments, guys! This will actually be my fourth amplifier. My first one was back in the early 70's - a homebrew pair of 572B's. Due to complete operator stupidity, that one nearly put me in the SK listing in QST. The plate cap assembly popped off and hit my right thumb, while my left hand was on the chassis. Burned a hole in the end of my thumb and knocked me across the room. 1,700 volts is pretty unforgiving. I disassembled it and never looked at it again. My next amp was a Heathkit SB-221. Very nice amp, but for a rig with two 3-500Z tubes, weak. I now understand that was mostly due to an "underpowered" power supply. Kept it until the mid 90's and eventually sold it. As I mentioned in my first post, I recently had an Elecraft KPA500 but sold it after about a year.

With those last three amplifiers, I never drove them to full output - I always thought it was akin to driving your car with the gas pedal floored all the time! The KPA500 had the ability to put out about 600 watts, but when I used it, I usually kept it to about 500 - 525 watts. I'd be willing to bet that the extra 50 watts or so would never be noticed on the receiving end. And, it just has to help the longevity of the amplifier's components. So, with the AL-811 that's been shipped, it'll be kept under 100% output, too.

I'll certainly take a good look inside after I unbox it, as I've now read several posts about the poor workmanship that may be encountered. Hopefully MFJ / Ameritron has also seen those posts and addressed them, but one never knows.

Also, I got a quote from a licensed electrician on having a separate 240V line run to the room the shack occupies. Flat rate of $250. Not too bad, and certainly a good backup option if I'm not happy with 117V operation.
Logged

Jim / W6JHB
Retired in Folsom, CA - and loving it!!!
Pages: Prev 1 [2]   Go Up
  Print  
 
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.11 | SMF © 2006-2009, Simple Machines LLC Valid XHTML 1.0! Valid CSS!