On Thu, Nov 23, 2023 at 02:19 PM, Kent Trimble, K9ZTV wrote:

According to the manual, at 120 VAC the maximum current draw for the LA-1K is 33 amps.

Happy Thanksgiving Kent,

On page 15 of the currently available LA-1K Technical Manual it states in part,?under the "POWER SUPPLY PERFORMANCE" section, "If the LA-1K is used with 120VAC the max current rating is 33A."? In other words, the medical grade power supply's (found in earlier version of the LA-1K) rated output current is 33ADC maximum, with an input voltage of 120VAC.

Please note that page 15 of the currently available LA-1K Technical Manual makes absolutely no mention of the magnitude of the AC input current associated with either 120VAC or 240VAC input voltage of the medical grade power supply.

Your thoughts?

73
Ray
KJ5MI
PS - Referring my 30-Mar-2023 post /g/la1k/message/1152 "Mr. Ward advised me to ignore the power supply information in whole, as printed on Page 15 of the technical manual (hard copy) that came with my LA-1K shipment, since Palstar failed to update their LA-1K technical manual."? Page 15, as currently written, doesn't apply to my LA-1K since the thing doesn't have the medical grade power supply in question.? For the benefit for our new members, Mr. Ward is the Palstar techician.

The concern is with the current draw, as Jerry Webb clearly and accurately posted. According to the manual, at 120 VAC the maximum current draw for the LA-1K is 33 amps.

It is false security to assume all must be well if circuit breakers rated at 20 amps don't trip. It is impossible to know what is happening to wiring behind sheet-rock, to the plastic connectors splicing them, and the insulation encompassing them.

In the realm of solid state amplifiers, to be safe the rule of thumb is:

120VAC supply: limit RF output to 500 watts

240VAC supply: limit RF output to 1500 watts

73,
Kent
K9ZTV

Hey Fritz,first off Happy Thanksgiving from Canada!

?

Second, those output numbers look pretty good to me, Honestly I never ran more than 700 or 800 with my old AL-80A so I doubt I would drive the amp with 55 watts even if I had 220 in the shack.

Thanks, 73, Rick

I have a 20A ~120V circuit with a single outlet for my LA-1K. These
are the amp's drive and output numbers into a dummy load.

5 in => ~150 out
10 in => ~270 out
15 in => ~400 out
20 in => ~500 out
25 in => ~600 out
30 in => ~700 out
35 in => ~800 out

Generally I run 10 or 15 watts input to a full-wave 160M loop using a
Palstar BT1500A tuner. After 17 months with amp I have no complaints
or concerns.

73 de n4jvp
Fritz

开云体育

Hi Jerry

Well to be honest I do not plan on running the amp at 1000 PEP. 600-700 is more than enough for my use.

My old AL-80A ran just fine on the dedicated 120 V circuit, but at full output it only drew around 12 AMP. I could drive that amp up to 1000 PEP output, but rarely ran it above 700 watts for use on 75 M SSB.

So for now I will simply drive the amp with less power and eventually get the 220 wired into the shack.

?

Hi Rick:
?My LA-1K has the Auto-Sensing power supply and does NOT have the 120/240VAC switch to select.? The label on my LA-1K rear panel (below the AC input receptacle) states "20AMPS at 120VAC. 10AMPS at 240VAC".? If you have a 15A / 120VAC circuit, then your 120VAC circuit is BELOW the recommended current draw for the LA-1K.? Even worse if there are other power consumers on the same circuit.??

I suggest driving the LA-1K at a lower level while using your 120VAC circuit. Or... In the alternative, put a clamp-meter on the power cord and measure what current the LA-1K ACTUALLY draws at various exciter levels. It'll work fine at a lower output level.? Pesky Ohm's Law at work.
73,
Jerry
KB1N

? ??

Thanks Bob that is good to know. And yes I will check that switch!

I will likely get a 220 run into the shack after I get the amp. Just need to pick up the 10/2 wire and outlet receptacle.

To those who also replied, thanks for the information.

Happy Thanksgiving
73, Rick

Hi Rick

My LA-1K is powered by 120V. I use the Icom IC-7300 with about 25 to 30 Watts output for SSB and get around 400 to 500 Watts out.

73, Claus (AE0S)?

Rick, I drive my LA-1K from the Icom 7610 with no more than 45 watts or less (depending on the band) and output is approximately 1000 watts.? The LA-1K is a fantastic solid state amp.? Enjoy!

There is no issue running the LA-1K with 120v.? I ran my amp on 120v for the first week until I was able to run a dedicated 240v line to my amp.? It works well on 120v but really performs on 240v.? I do not foresee any problems as the LA-1K is designed to operate on both voltages.

Hello Everyone

?

I will be picking up my new LA-1K sometime early in December.

?

A few questions for current owners.

?

I presently have a dedicated 120 V line into my shack, with a 15 amp breaker.

For years I ran an Ameritron AL-80A on this circuit, up to 800+ watts at tines with no issues.

So I am wondering if the LA-1K will be fine at reduced power output (700-800 watts PEP on SSB) on that same circuit.

I will eventually get around to running 220 into the shack once I pick up some wire etc etc.

?

But for now I would like to run it off the 120 V line.

?

Does anyone foresee any problems with that?

Thanks, 73, Rick VE3PP

Hello Everyone

?

I am going to order a LA-1K today.

First solid state amp for me.

I am curious as to the various drive power that is required with this amp.

For example 25 watts drive, what is the output from the amp, Etc etc.

For now I will be running mine off 120 V until I can pull a 220 line into the shack.

Thanks, Rick VE3PP

On Thu, Nov 16, 2023 at 03:11 PM, James wrote:

The amp works without issue, really like having a 1Kw radio on hand plus instant band changing with a cat cable.

Hello Jim,

Looking at your QRZ page and my QRZ page I see that we are currently both using the Yaesu FTDX101D as the exciter.? Btw, I still have my LA-1K.

When I used to pair the LA-1K with my FTDX101D, it sure felt like having a 200W transceiver driving the LA-1K with much reduced exciter RF power.? However, feeling can be deceiving since it isn't like having a 200W FTDX101MP in terms of just its transmitter capabilities.? Please check out my 9-May-2023 post /g/la1k/message/1285 and I am quite sure you will see the subtle differences.

The Elecraft KPA1500/Yaesu FTDX101D combo, as seen on my QRZ page comes closer to having a 1kW transceiver (FTDX101KW?? lol) driving the KPA1500 with reduced exciter RF power.

73
Ray
KJ5MI

The amp works without issue, really like having a 1Kw radio on hand plus instant band changing with a cat cable. Nice that 40 watts drives it to a kilowatt.

On Wed, May 10, 2023 at 01:05 PM, Fred, W9KEY wrote:

Geeeez - I'm in awe of the extraordinary amount of bitching & complaining over a silly burned out bulb in a switch!
Just imagine if something serious.happened!!

Hey Fred, when searching for a schematic drawing package for the LA-1K, I came across John Whitt's webpage (AI4FR) where he has a detailed account of numerous serious issues relating to his brand new LA-1K.

This link will take you to said webpage.? Please read it very carefully to fully appreciate the serious nature of the problem.

Oh btw, you will find in this post /g/la1k/message/1436 seeing other LA-1K owners, having like issues, might tend to agree with Mr. Whitt (AI4FR) that "In the end I have learned that Palstar makes a great tuner but that can not be said for the LA-1K which I think is their first venture into amplifiers. They are happy to take your order but if there is an issue it will be your fault. Also, question them at your own risk..."

73
Ray
KJ5MI

On Fri, Oct 13, 2023 at 05:28 PM, David Hussey wrote:

Forgive my ignorance, but what is “pure signal” ??

Hi David -

This DX Engineeering link will take you to a review of the LA-1K by Dr. Terry G. Glagowski, W1TR, published back in 2018.? Dr. Glagowski made mention, throughout the article, of the term "PureSignal" that you might find helpful.

73
Ray
KJ5MI