- Amateur Radio (Ham Radio) Community

Call Search

New to Ham Radio?
My Profile

Friends Remembered
Survey Question

DX Cluster Spots

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

Reviews Categories | Amplifiers: RF Power - HF & HF+6M | Palstar LA-1K LDMOS Amplifier Help

Reviews Summary for Palstar LA-1K LDMOS Amplifier
Palstar LA-1K LDMOS Amplifier Reviews: 14 Average rating: 4.9/5 MSRP: $3795
Description: The LA-1K is a RF Sensing Dual HF LDMOS 1000 Watt
Amplifier. While the LA-1K will work with a wide variety
of tuners and transceivers, Palstar custom-design the LA-
1K to work as the perfect match for our very popular HF-
AUTO autotuner. Made in the USA
Product is in production.
More info:
Email Subscription
You are not subscribed to this review.

My Subscriptions
Subscriptions Help

You can write your own review of the Palstar LA-1K LDMOS Amplifier.

Page 1 of 2 —>

W1DT Rating: 5/5 Jun 18, 2019 00:50 Send this review to a friend
Excellent Linear Amplifier  Time owned: 0 to 3 months
I have owned the Palstar LA-1K now for 1½ months and am extremely happy with it for many reasons. The first is quality; it easily meets my high standards. Palstar uses nylon washers on the cabinet screws to prevent the heads from scratching the paint. That level of attention to detail is rare and is a good indicator of the design and build quality throughout. The second is ease of use. Most solid state amps are easier to use than tube amps, but the designers of this unit went the extra mile to make the LA-1K easier to operate than other solid state options. The third is solid performance. In the time I have owned it, the amp has never experienced any faults or unexpected behaviors of any kind.

I expect many operators are like me, very sensitive to ambient noise since we want to hear the audio from the radio without being distracted. The LA-1K does well is this regard. It sits on my bench directly adjacent to my radio, but its fans are not loud enough to disturb me during normal operation. On the rare occasions when I get going in a long QSO, the fans will speed up and become audible. In these cases I turn up the radio volume to compensate. Based on my experience and discussions with other operators on this topic, my assessment is that the LA-1K is a relatively quiet solid state amplifier. I believe part of the reason for this is the design; the fans are internal so the cabinet provides some attenuation. Also notable is that the thermal design does a good job of keeping temperature down; this is important since high temperature is the enemy of electrical components. Thus, the design did not sacrifice cooling capacity to achieve the relatively low noise level.

The LA-1K has the ability to report status and be controlled via the RS-232 interface. I purchased an inexpensive RS-232 to USB converter and verified the interface works exactly as specified by Palstar. I also compared the digital RF power and SWR readings against other calibrated instruments and found the LA-1K to be very accurate. The RS-232 interface is a nice feature since it enables remote monitoring and control of the amp. I’m in the process of developing a simple PIC microcontroller based control box with a 4 line by 20 character display to provide this capability locally. This will enable me to move the amp off of my crowded bench but still operate it with ease.

My main radio is an IC-756Pro and there is no way to adjust the Tx delay. Icom also does not specify it in any of the manuals, so I made the appropriate measurements. The delay from PTT going low to start of RF output (Tx Delay) is 10msec. The delay from when RF power stops to when PTT goes high again is also 10msec. Since the Tx delay is greater than the 6msec required by the LA-1K when set to the “DIRECT KEYING” mode, I operate that way to ensure no stress to the amp. I also can’t and don’t get the small SWR spike mentioned in an earlier review.

I did a lot of research on the available solid state amps before buying the LA-1K and it paid off; I am extremely happy with my LA-1K. Part of this involved many questions for Palstar and they answered all of them in a timely and comprehensive manner – thanks Mark! Technical support is very important when buying a large ticket item so this was another factor that lead me to the LA-1K. Another outcome of my research is that the LA-1K offers excellent value. This was further reinforced after I received my unit and observed the super quality first hand.

I highly recommend the LA-1K to anyone in the market for a solid state 1KW class linear amplifier.
N9CHM Rating: 5/5 May 21, 2019 19:28 Send this review to a friend
EXCELLENT amp, very pleased  Time owned: 0 to 3 months
The amp is beautifully engineered, and works exceedingly well. It gives me a KW radio wherever I go from 160M to 6M (well...950W on 160M, a KW everywhere else). I get unsolicited reports of how clean my audio is at 1KW (both audio reports and looking at my signal spread on a panadapter). I switch between my IC-7300 and the FLEX 6500 with a coax switch, just ran a Y-connector for the RCA phono relay to the amp and I can run both radios into the Palstar and I don't need specific band data cables for either radio due to the RF sensing capabilities of the amp, just a quick mic click and it's ready...simplifies my operation and allows for rapid band switching without retuning like I had to do with my ACOM 1500 (loved the ACOM, it is still my choice for a legal limit tube amp). The small size and weight of the Palstar is another plus factor when moving things around the desk, when needed. And finally, my conversations (before purchase) with Eva at Palstar were very helpful, and much appreciated. Fine people to do business with in support of equipment made, and serviced, in the USA.
AI9F Rating: 5/5 May 19, 2019 22:49 Send this review to a friend
Great Buy new purchase  Time owned: 0 to 3 months
I just purchased one at the 2019 Dayton now Xenia HamVention, it is a fantastic Amp. no tuning auto sensing of frequency, very easy and simple to use. I was using an older Yaesu FL2100F with 2 572Bs, could hardly pick it up, you could fry an egg on it! This is wonderful technology. So far this is a great addition to the shack. I also use the Palstar AT2KD and have used the Palstar AT500 tuner all worked great never have had any problem.
W9DZ Rating: 5/5 Mar 13, 2019 23:19 Send this review to a friend
Very Impressive  Time owned: 0 to 3 months
I have been using a Acom 1000, an excellent amplifier, for over 4 years. I have never had an issue with it but I wanted to try a no-tune solid state amp as it better suites my type of operation. I like to do search and pounce type operation during contests with frequent frequency changes moving from one end of a band to the other. This required frequent re-tuning of the Acom, especially on 80 and 40M. I have had the Palstar for a little over two weeks and used it during the recent ARRL DX contest. I have teamed it up with a MFJ-998 autotuner. Operation was so smooth, moving up and down the bands without doing anything other than twisting the VFO knob.

An earlier review here on eHam mentioned an issue with the SWR seen by the transceiver on initial key up, especially on CW and data modes. When operated in the normal or default mode there is a 20.5 msec delay before all T/R switching is complete. Increasing the TX delay on your radio to 25 msec is the easiest solution. Total T/R switching time can be reduced to 6 msec by adding a band data cable between the radio and the amp and choosing the direct keying mode in the amplifier menu. I have done this with my IC-7300 and set my TX delay to 15 msec.

I would not hesitate to recommend this attractive and well built amplifier, made in the USA, to anyone considering no tune operation.
K4MJO Rating: 5/5 Sep 29, 2018 22:24 Send this review to a friend
My Dream Setup Finally.  Time owned: 6 to 12 months
Get the LA-1K amp to have your own DREAM to watch. Thats all you do. Set the freq, Click the mic and then key up and talk. NOTHING else to do, setup, change, check or even watch. It is a dream. If you live near me, Come see it operate.
Job well done Palstar. I love watching the work this thing does so well. It is unreal. It will give me over 1200 watts at 55 watts in so I run it at 50 watts in, I love this system. I bought a al-80 to use with my new Kenwood 590 SG but saw the Palstar had been released and bought it. This system is the answer. Place it on the HF-AUTO Tuner and the Dream gets way better. Sammy, K4MJO
K3QYE Rating: 5/5 Jul 30, 2018 20:14 Send this review to a friend
Excellent Light weight, conservitively rated, easy to use.  Time owned: 0 to 3 months
Have a HF-Auto tuner, and have been using an AL-1500 boat anchor. Had to rearange the shack and the AL-1500 is just to heavy for these old bones. Picked up the LA-1K from HRO. Read the directions, and had it up and running with my Yaesu FTdx-3000 in 20 minutes. Touch screen makes it simple to use. While only rated for a KW I have to turn the input down to 30 watts to keep it under 1200 watts. Great engineering job and highly recommend this amp.
KD0ZV Rating: 4/5 Jul 20, 2018 13:03 Send this review to a friend
Nice amp but not perfect  Time owned: 3 to 6 months
The LA-1k is well built and has beautiful construction typical to everything Palstar builds.

I am only giving it a 4 for the following reasons.

1) Terrible documentation (typical to Palstar).

2) Has high SWR spike when you first key it even on a resonant antenna until the amp does all its switching to the band you are on.

3) The fan comes on quickly when running CW or digital even at less than half of rated power for those modes. It ramps up to what I consider real noisy while operating but cools down quickly. I guess this would tell you it has plenty of cooling capacity in the fans but might lack in heat sink? At first I wondered why Palstar does not give you the option to switch to Fahrenheit on the display for temps but the temp swings would be much more prominent if they did.

4)Noisy keying relay. Makes a racket when sending CW.

All in all its a fine amp and has not missed a beat. The display is very nice and like the touch screen a lot. Does not have all the bells and whistles other amps like Expert or Acom have. I dislike the USB connector and button on the front for programming. Might be convenient but looks bad.

I would buy it again and would recommend it to others but the relay noise might be a deal breaker to CW operators that prefer something quiet like the Elecraft.
KB8LS Rating: 5/5 May 23, 2018 23:53 Send this review to a friend
Highly Recommended  Time owned: 0 to 3 months
I picked up the new LA-1K amp during the 2018 Dayton Hamvention. Below are my initial impressions and test results.

Many solid-state HF power amps are only rated in terms of Peak Envelope Power (PEP). This type of RF power rating can be misleading to the unsuspecting Ham. For example, if a solid state amplifier is rated at 500 watts PEP, without stating the transmit (on) time versus off time, the operator can rag chew at 500 watts for 30 miniutes, the amp overheats and shut down and still be within the 500 watt PEP specification. In other words, the PEP rating allows the amplifier to be poorly designed and can result in shut down due to insufficient cooling.

As of this posting, the Palstar LA-1K is the only solid state HF amplifier that specifies the RF power output rating as “Intermittent Commercial and Amateur Service” (ICAS). ICAS is a more severe rating than a PEP rating. The only rating that is more severe than ICAS is Continuous Commercial Service (CCS), which means an AM modulated carrier wave transmitted continuously 24 hours per day, 7 days per week, 52 weeks per year etc. except for shut down for maintenance.

The Palstar LA-1K ICAS rating is specified at 1000 watts “Single Side Band voice duty… there is no time limit on transmit time” at this power level. This means you can rag chew indefinitely without the fear of the amplifier overheating. In the CW mode, the RF power output is specified at 850 watts, five minutes on and at least one minute off. For FM and RTTY the RF power output is specified at 500 watts*. For AM the RF power output is specified at 275 watts* (*every on period must be followed by an off period of the same or longer duration). In order to achieve the power ratings above the LA-1K has a well designed cooling system that provides sufficient air circulation to prevent overheating. If any of the ratings above are accidentally exceeded and the internal temperature rises above 100 degrees C, the amplifier automatically switches to the bypass mode. When the temperature drops below 70 degrees C, the unit reverts back to the operate mode. The fans are whisper quiet in the standby mode and are barely noticeable in the rag chew mode.

Upon initial installation of this amplifier, I found that between 30 and 40 watts of drive would produce just over 1,000 watts of RF output power. If the drive is increased to 50 watts, the output power is 1,100 to 1,200 watts.

The amp was setup for 230 volts AC operation. “Power In” was measured with a Bird 43 with a 100 watt slug. “Power Out” was measured with a RF Applications digital wattmeter into a Bird model 82 dummy load. ALC between the exciter and amplifier was disconnected.

The LA-1K uses a vacuum relay for transmit/receive change-over. The amplifier has provisions for up to three antenna outputs and uses three separate relays to switch between antennas.

After several on-the-air rag chew sessions lasting up to an hour, the fan speed would automatically increase to keep the amplifier cool, but the amp never overheated and shut down. I paired this amp with the Palstar HF-Auto automatic tuner. This combination really spoils one use to twisting knobs after a frequency change – there are no knobs to twist for tune-up!

Nice work Paul! I highly recommend the LA-1K – You will not regret this purchase.
N0SP Rating: 5/5 Apr 24, 2018 07:57 Send this review to a friend
It's a keeper...   Time owned: 0 to 3 months
Well, I have resisted making the change from familiar tube amplifiers (I have three of them) to solid state systems. I never cared for their propensity to pop with a few milliseconds of abuse. The lack of sensory feedback with transistor amps as to what's going on (clang of relays, plates glowing red, etc.), and the ability of tubes to take a glitch or ten and keep on working, have kept me in the high-voltage camp. When I first saw that famous video of an LDMOS amp running full power in to a 65:1 SWR, setting it's board on fire, and STILL functioning, I got mildly interested.

At that point, reliable commercial LDMOS amps from reputable companies were still years away as there were *significant* technical challenges in getting them to work right. I even considered one of the LDMOS "kit" amps, but reading the home-brew LDMOS amp blogs made me crazy and I began to think nobody would take this on commercially. Concerns about proper bonding, cooling, and dealing with the very low native impedance of the devices (2.5 ohms) were significant issues. When finally announced (recently) they were VERY expensive... like $7k(!), and still not delivering. Actually, at the time of this writing, only Palstar is currently able to ship an LDMOS amp at a "market price" for this power level. The only other offering out there is severely back ordered and (according to reveiws here) seems prone to problems. Further, the LA-1K is the only certified one available thats made in America. (unless you want to pay SIX THOUSAND dollars for the Elecraft) If something goes wrong service is in Ohio, not Outer Slovobia!

Once I put this in service I realized how much "work" I had shed in changing bands and frequent tuning. This thing is crazy-easy to operate and performs exactly as advertised. All I do is click the mic, or "dit" the keyer and this amp has switched bands, selected the proper antenna port, and is ready to go. It does so with no connection to the tranceiver except the coax jumper. It works the same whether it's my vintage 1960s AF-67 transmitter, or 756PRO. It simply detects the frequency and instantly changes band/antenna. (three antenna outputs on back)

I'll start by saying I've always been partial to Palstar. I have two of their big tuners, one for 14 trouble-free years, several shack accessories, and their awesome R30 receiver is still working great since about 2002. I almost NEVER buy an expensive new piece of equipment off the shelf. The last time was a new Yaesu transceiver in 1996, (reluctant to spend the money) but after having an opportunity to play with an LA-1K last month and hearing a guy running one on AM(!) at 300 watts carrier (sounding wonderful), I knew I had to have one.

When it arrived two weeks ago I didn't even hook it to an antenna at first. I slapped two Bird line-sections to it's rear panel (INPUT & OUTPUT terminals) and with two Model 43s connected to the line sections I started making measurements of input vs. output. I was VERY impressed. As is common with HF/6 amps, I was sure I'd find some roll-off in performance either down at 160 or up at six meters. NOT! This thing was as hot at 1.9mhz as it is at 54mhz. I wrung it out on every band at several power levels in to a precision dummy load that reads 50.0 ohms on my Fluke. I even thought of putting the value for every band here, but no need. Output numbers for a given input power are within about 5-7% on every band all the way from 1.8 to 54mhz. I changed slugs to keep the readings somewhat mid-scale to enhance accuracy. I couldn't believe how "tight" the LA-1K was across the entire spectrum. No small feat.
Results are below, displayed as inputW/outputW
25/650 (25w level had some variation between 610 and 705 depending on band)

I then hooked it to the antenna and proceeded to "ride it hard and put it away wet" for over a week. What a joy to use!... bright front panel color LCD displays your exact operating frequency, power output, SWR, heat sink temperature, voltage and current to the finals, as well as selected antenna port and band in use. So, there's still lots to "look at", but nothing to "do". The amp does it all for you.

One thing I worried about a bit is cooling. I live at 9,000ft elevation where air-cooled systems are somewhat compromised by the low air density up here. I deliberately ran a few 5 to 10 minute diatribes at full power and never got the heat sink temperature higher than the mid-40s (degrees C, amp shuts off at 100 degrees) The 3-speed fan adjusts with increasing heat, but never gets loud. I held it key down on FM for quite a while and the temperature approached 80. The fan at full speed is still much quieter than any of my Ameritrons, not even close. Quiet is nice! With AM operation at 275 watts it never got close to cut-off temperature.

Some happy things I discovered after delivery...
1) SWR protection cuts in at 2.5:1. Notably, the amp doesn't care how much power you're running. Whether 20 or 1000 watts, at 2.5:1 it faults to STBY, period. If you correct the condition, amp comes back on upon next key-up.
2) Wattmeter bar graph is very accurate and tracked nicely with my Bird 43. Watt meter automatically changes scale in standby mode so you can accurately set drive power prior to engaging the amp.
3) The internal power supply! This thing is amazing. There is NO voltage sag at max power. I peeked in and looked up the module used by Palstar then looked up the specs. It's a commercial industrial/medical grade unit which has it's own internal high-current/short-circuit/temperature protections and two temperature-controlled cooling fans. (never hear them tho) If the power supply shorts or overloads it simply shuts off, and comes back on in about 2 seconds. While inside the cabinet I couldn't help but admire the quality of Palstar's construction... VERY solid.
4) TWO year warranty (rare in ham radio circles)
5) This amp is SO light and quiet. I've always associated high power with noise, weight, and all sorts of drama. The hardest part of installing this amp was lifting the 77-lb Ameri-Monster-Tron off the desk to make room for the LA-1K.
6) SWR readout on display is in actual numbers (eg. 1.2:1) rather than a bar graph and continuously displays the value as you transmit. I found it to be very accurate.
7) Palstar ships the amp with two power cords. Both the standard 230v plug used by other manufacturers and conventional 3-prong 120v cord come in the box. To change voltage you just change the cord, no changing jumpers inside the cabinet.
8) Clean clean clean... I began getting un-solicited reports on how good my audio was... these of course are subjective, but the beauty of these LDMOS devices is the great 3rd Order IMD number which is well in to the -30s with Palstar's implementation. (LDMOS amps can be dirty if not set up correctly) The LA-1K has a "Pure Signal" output port in the back for the modern radios using that feature to get 3rd-order way down in to the noise... -60db or better.
9) While I'll never use them, the amp has data connections on the rear for communicating with Elecraft/Kenwood/Yaesu/Icom, etc. The manual lists detailed pin-out info for any kind of remote control, either by computer or another radio.
10) Thoughtful design... it seems Palstar anticipated everything. Even when the amp is in STBY it will change bands when you key the exciter for tune up. Again, LOVE the re-scaling of the internal wattmeter bar graph for very accurate setting of drive power.

In summary, I am very happy with this unit. Apologies for the LONG read here, but there was much to say. I think this is a ground-breaking product at a fair price. It's a well-built full kilowatt in a single 26 pound package that will fit in the overhead bin for a nice hamcation. HIGHLY recommended.

AA9NN Rating: 5/5 Apr 4, 2018 15:05 Send this review to a friend
Very well designed Amp  Time owned: 3 to 6 months
I purchased this amp from HRO in Milwaukee, very light amp for a KW out. As I did a deeper dive into the construction and power supply they used, the more impressed I was.
you have to run this on 220V to get 1200 out, although I did try 120V and got 800 watts out no problem. Not a lot of controls on the front!! auto band switching takes the guess work out that your configured correctly!
I did call Palstar as I did have some questions. Talked to Paul directly. I recommend a call if you have concerns after looking over the manual on line. Yes, I'm a bit biased as I own a couple of HF auto's (which are the best auto tuners PERIOD) The LA-1K is quiet, runs pretty cool, and makes just over a KW. Built in Ohio and has a 2 year warranty. so, so far so good! :)
Page 1 of 2 —>

If you have any questions, problems, or suggestions about Reviews, please email your Reviews Manager.