Legal Limit Solid State Amp - SPE 2K-FA, KPA-1500 or ??

mikeatthebeach .

If you set your power out to 100mW maximum, you will always be WEAK SIGNAL
to everyone !! They may never hear you as well !! 
Hi ! Hi ! Just having fun here !
73 Mike

mikeatthebeach .

When running FT8 at 1.2Kw If you do not overdrive the Audio and 
do not overdrive your ALC, you can get a really clean FT8 signal
as Howard mentions above

Newbies into FT8 misunderstand this confusing this with the Weak Signal to Power Out debate - etc !

You can run High Power as long as you don't splatter !
73 Mike

Roger_W6VZV

Thank you.  I used to say that about PSK31 and people thought I was nuts for running 100 watts (occasionally a lot more) when busting DX pileups.  I just racked up the countries and contacts and kept smiling.

Bill W2PKY

PGXL will sustain 1.5KW on JT65 45 sec on, and with a very low SWR, not much fan noise.

Ria

So out of those arguing here, I notice none of you have a PGXL. But I do. The reason it can do high duty cycle on digital modes is because it can dynamically change bias did SSB and CW/digi. The bias in CW and digi is class AB and SSB is “AAB.” AAB runs considerably hotter and is less efficient. But IMD is way better. Also the PGXL has a vapor phase heat sink for fast recovery. The KPA1500 doesn’t have this. It’s a good amp but it doesn’t have this. Where the KPA1500 excels is that the PSU is separate so it’s heat doesn’t affect the PA module. There is also no harmonic load and associated thermal management but this is 6 of one, half dozen of the other. I’m indifferent but supposedly the harmonic load enables better IMD, at the expense of some fan noise and cooling requirement. BTW tube vs solid state and heat - there is a definite difference. Solid state amps only generate heat when transmitting. Tube amps must be heated all the time. I had an Alpha 91B and AL811H running here. The shack is noticeably hotter with those than when I was running either the PGXL or SPE 1.3K. Of course solid state vs tube in price - no debate there but there is a reason a Tesla starts at $75k and a gas powered luxury car costs less. New technology always costs more in the beginning. Wait until MFJ finalizes their design (I’m sure they’re working on it) then prices will drop like a rock.

Varistor

Is the variable bias automatic or must be selected by the user? Would be great if the former, blah if the latter. I do not know a single Acom 2000A user who bothers changing the bias to improve efficiency (or maybe because the Acom is so quiet as is).

Ria

Automatic, based on radio mode via Ethernet or it profiles the waveform via RF sensing. MEffA also works by profiling the waveform and adjusts the voltage for maximum efficiency. MEffA can be turned off as well.

Ria

The real advantage of solid state is instant everything. Instant on, instant band switching. In fact this is the reason PGXL can do SO2R. It’s great for remote operation which is why RHR is using solid state amps at their remote sites, except on dedicated 160 where they are using mono band amps. Tom W2SC/8P5A uses a homebrew solid state design too.

David Livingston

I have had the Expert 2K-FA for over a year.  I love it. Works perfectly. Tuner is Fantastic...!!!

David Livingston

I have the Expert 2K. It will run well over 2K into a dummy load all day long...!!!

W2NER

Chris - I know of a few Ham's that purchased the RF-Kit amp and had nothing but problems getting it to work.  Its not a plug and play amp, you not only need to assemble it but also do the alignment and if you don't get that just right, your power will suffer.  Not for me but to each his own.  Also, if you ever need to get repair work done, good luck.  I have a friend that purchased two of them and after assembly he never was able to get them working.  Took two months after he sent them in to get his money back.  Nightmare... 

roger palmer

Having owned and used the SPE 2K-FA and the KPA1500 and the PGXL.
My observations. I am a normal operator, no contests, no RTTY, no AM.
*SPE 2K quiet, internal tuner outstanding with SWR less than 2.3 -1. complete computer and remote controlled. Excellent. Legal limit plus on SSB & CW
*KPA1500 a tad more fan noise than the SPE 2K, internal tuner excellent, more tolerable to SWR than the SPE. completely remotely and computer controlled.
*Power Genius. of all three amps compared here, the Fan Noise is more constant and  noticeable. NO internal tuner of course, but completely remotely and computer controlled. Legal limit plus a little.
All of these listed amplifiers are relatively competitive in price, but an internal automatic tuner with memories is a must for me.   

David Decoons, wo2x

One of the testers ran the PG XL in RTTY SO2R. It did not back down in power. That is one of the toughest duty cycles. My PG XL puts out legal limit on all bands/all modes. No backing down on this amp. And the integration with the Flex is top notch. Dave wo2x

W2NER

I think 95% of the ham community would be very happy with a SPE 1.5 or 2K

KY6LA_Howard

More likely 80%. Definitely not contestors and FT8 DX Hunters. As I said. I am personally frustrated with my 2K as it clearly was represented as a Full Power ALL mode amp which it clearly is not.

KY6LA_Howard

By contrast the PGXL uses 2 x MRF1K50H: 1500 W CW over 1.8-500 MHz, 50 V Wideband RF Power LDMOS Transistors. So clearly lots more headroom with 2 x 1500 vs 2 x 1270W for the more limited KPA1500 I Saw the B26 Amp at Friedrichshafen where it was running 2 x 1700W LDMOS BUT please continue to amuse us with your trolling for Elecraft.

Roger_W6VZV

Is there really any significant difference between 1KW and 1.5KW?  Don't think so.  The thing I like about the PGXL is that the support is backed by Flex and not some independent who may be gone tomorrow.  But 7 bills is a lot for an amplifier.  Too bad Yaesu won't upgrade the 20 year-old design on the Quadra.

Bill -VA3WTB

What you are paying for in the PGXL is an amp that can do 1500w key down with ease. And that the amp stays really clean while doing it, And that it is Pure Signal ready. So it is priced at the higher end with other amps costing even more.
 Some amps cost around $10.000, what do we say about them?

W2NER

all the SPE amps come with the pre-distortion interface and are no dirtyer then any other amp. it’s all in the way you use it. you can get ANY solid state amp to be dirty if you push it to the limit and i don’t care who makes it.

Chris DL5NAM

Bill that's right, but be fair: there also amp with predistortion output, automatic tuner, remote without PC,1,5KW key down (based on BLF189A or BLF189B) for 3500$.

So it's up to every Ham to select (buy) what he need and what he can spent money.

W2NER

SPE amps have more features and protection then most.

David Decoons, wo2x

Nick I disagree about the “cleanliness” of the SPE 1.5k. An acquaintance of ours has one and it is worse than his other two amps. Dave wo2x

David Decoons, wo2x

Chris, The RF Kit tuner is not automatic (yet). Don’t know when/if it will be. Dave wo2x

Chris DL5NAM

it will be ,in short - still final test Chris DL5NAM

W2NER

All I can say is mine was VERY clean even with my 7610 I had.  He has a amp with a problem or he is over driving it.

KY6LA_Howard

@Nick You are only partially correct About over driving an amp to make it dirty. The question then becomes how much headroom you have in the app design. Clearly the SPE amP do not have enough thermal headroom for full power on FT8. Nor do they seem to have enough RF Power headroom when driven near the legal limits on FT8. They seem ok on SSB.and have plenty of RF headroom there

Ken K7YR

On occasion I find content humorous .......

Solid state VS Tube,  "Takes too long for the tube to warms up".  The solution is to leave the filaments on!  Install your headset over your ears, this should make up for the .97 Dbm noted below and remove any fan noise.

1,200 Watts vs 1,500 Watts, a .97 Dbm delta?  One "S" unit is 6 db.  What am I missing here?

Sounds like a lot of "Braggarts" willing to spend big $$ for an added 300 Watts.  I would submit that "Skill" will always play a roll over brute strength.

Burch - K4QXX

I can't tell you how many times I have come into the shack on a Saturday morning with a cup of coffee and turned on the radio to tune around for a few minutes where I have heard DX that I need.  By the time I turn on my Ten Tec Titan (which I really love) and wait for the 4 minute warm up, there is a huge pile up.  Heard China in here a few weeks ago from Florida.  Guy was calling and calling and no one coming back to him.  I called and called him on 100 watts (while waiting for my amp to warm up) and he couldn't hear me.  With all the DX clusters and the instant information age, by the time my amp kicked in, there was a huge pile up and I didn't work the station as I only had about 15 minutes before I had to leave the house.  That occasion, I didn't find the 4 minute warmup humorous.  Is that worth paying for a solid state amp?  That is up to the individual.

Burch

K4QXX

KY6LA_Howard

1 dB is the difference between being copied at -24dB on FT8 and not being decoded at -25dB

Bill W2PKY

The EME crowd wants every watt they can get.