AEA LA-30 Amplifier.. Good amp?

[ExitThirteen]

Howdy all! I just recently made a purchase of an Advanced Electronic Applications LA-30 linear amplifier. It uses a single 3-500Z in grounded grid AB2. 1200W SSB input, 1000W AM/FM/CW input. Looks to be a nice amp from what I've read.

Does anyone here have one, or know much about them? Are they pretty reliable and stable? Looks like they can be modded for 10/12M use, has anyone done that? An inquiring mind would like to know. Any/all info would be most helpful. Thanks in advance!


~Cheers~

 

[RADIOOMAN]

Howdy all! I just recently made a purchase of an Advanced Electronic Applications LA-30 linear amplifier. It uses a single 3-500Z in grounded grid AB2. 1200W SSB input, 1000W AM/FM/CW input. Looks to be a nice amp from what I've read.

Does anyone here have one, or know much about them? Are they pretty reliable and stable? Looks like they can be modded for 10/12M use, has anyone done that? An inquiring mind would like to know. Any/all info would be most helpful. Thanks in advance!


~Cheers~

I don't know what information you have available but what I am seeing on the schematic is the input circuit for 10 meter should already be present.

 

[hookedon6]

the AEA la 30 design has been around for years, it was sold to Heathkit, and later to Ameritron.

the weak component is the origional power supply.
as old as this amp is, I would look closely at the caps.

out of the box , it is a 10 - 160 amp

 

[Captain Kilowatt]

the AEA la 30 design has been around for years, it was sold to Heathkit, and later to Ameritron.

the weak component is the origional power supply.
as old as this amp is, I would look closely at the caps.

out of the box , it is a 10 - 160 amp

I noted in the manual it stated the power transformer was rated at only 600VA. For a 1200 watt pep output amp that is running pretty much on the ragged edge.

 

[ExitThirteen]

I don't expect the amp to do 1200W... it's rated at 1200W input. The 3-500Z is a 10x tube, and about 65% efficient. That being said, 1200 times .65 = 780W. That's about what I should be getting. I'd be happy with that.

~Cheers~

 

[Captain Kilowatt]

I don't expect the amp to do 1200W... it's rated at 1200W input. The 3-500Z is a 10x tube, and about 65% efficient. That being said, 1200 times .65 = 780W. That's about what I should be getting. I'd be happy with that.

~Cheers~

Yeah I did say 1200 output didn't I. That was a typo, force of habit kind of thing. I meant input. 1200 watts pep input is still running on the ragged edge with a 600VA transformer. 1200 watts OUTPUT would be just plain ludicrous.

 

[ExitThirteen]

I did a little number crunching. It says in the manual that it has 3000V at idle, and max current on the the transformer is at 600mA.... so I did some figuring..


Obviously, on keydown (especially at 110V) I'm gonna drop some of that voltage, so I'll de-rate that 3000V down to 2600V. And I'm not gonna use the full 600mA of the transformer, so I'll go with 500mA.

So if I counted my all my fingers and toes right, 2600 x .5 = 1300W. At 160-20M I'd probably rate the efficiency of the tube @ 65%, so 1300 x .65 = 845W out on SSB. Not too bad!

I know efficiency drops off a bit from 15-10M, so I'm gonna give it 50% on those bands. Again, if I count my fingers and toes right, 1300 x .5 = 650W out on SSB on those bands.

Do these numbers seem reasonable, or am I off base here? I'm trying to get some real numbers, nothing over inflated, no "CB Dosy meter" watts, just some good honest numbers. I'm curious if my numbers make sense.


~Cheers~

 

[RADIOOMAN]

I did a little number crunching. It says in the manual that it has 3000V at idle, and max current on the the transformer is at 600mA.... so I did some figuring..


Obviously, on keydown (especially at 110V) I'm gonna drop some of that voltage, so I'll de-rate that 3000V down to 2600V. And I'm not gonna use the full 600mA of the transformer, so I'll go with 500mA.

So if I counted my all my fingers and toes right, 2600 x .5 = 1300W. At 160-20M I'd probably rate the efficiency of the tube @ 65%, so 1300 x .65 = 845W out on SSB. Not too bad!

I know efficiency drops off a bit from 15-10M, so I'm gonna give it 50% on those bands. Again, if I count my fingers and toes right, 1300 x .5 = 650W out on SSB on those bands.

Do these numbers seem reasonable, or am I off base here? I'm trying to get some real numbers, nothing over inflated, no "CB Dosy meter" watts, just some good honest numbers. I'm curious if my numbers make sense.


~Cheers~

I got no problem with your numbers.....looks to be in the ball park to me.
The manual does say the effiecieny is 50% on 10meter.
I guess running it on 240vac is not an option according to the schematic.

 

[ExitThirteen]

Didn't see that part about it being 50% efficient on 10M.


About it being a 110V only unit, I am a little disappointed about that, didn't know until after I had purchased it, but I suppose if push comes to shove maybe I can find me a decent transformer that has the 220V capability, and stick it in there down the road. Would LOVE to get some Peter Dahl iron to put in that baby...


But for now, I think this will serve my purpose.

Also interesting to note that it says in the manual that 50W PEP will drive it full output, 60W PEP will drive it max output. Is this even possible for a 3-500Z? I was thinking they needed something in the 85W area to drive full output....


~Cheers~

 

[Captain Kilowatt]

I think 85 watts of drive is what it would take to drive it to what the tube is capable of making but not with that plate voltage. A 3-500Z starts to really shine with about 4 Kv on it.

BTW I think the numbers you ran are right in the ballpark considering the power supply limitations.