SPE Expert 2K-FA has a built in ICAS-type duty cycle in that it automatically
shifts to MID or lower power when the duty cycle on HIGH is more than its
system can handle. In use, I have found that I do not talk too long to have
the switch downward but that if I use 10 wpm on CW, the amp will soon switch
down. At 20wpm and higher, it stays at HIGH.
Amp switches down to MID within about a minute of RTTY. This behavior
indicates that the amp would be rated about 800 watts real ICAS and maybe
300watts or so CCS. The SPE instructions are clear and honest about these
behavior facts (but omits numbers).
The established ratings of CCS and ICAS for years has had some good meaning for
amplifier discussions. The usage has gone with sales dept advert writers who
know their products are not near CCS or Brick on the Key products. Of course,
old Alpha advertised CCS and their earlier amps were sold for kw DIATHERMY
medical use.
If your amp can not be used for DIATHERMY, it is a ham radio smaller toy.....
not useless but..... I use my 2K-FA reasonably and am very happy with it.
73, Charly
________________________________
From: Amps <amps-bounces@contesting.com> on behalf of Jim W7RY
<jimw7ry@gmail.com>
Sent: Monday, December 25, 2017 2:30 AM
To: kstover@ac0h.net; 'Amps group'
Subject: Re: [Amps] NXP 65V LDMOS 1K80H-1800W
How much for an 8877? And this is a 3CPX1500!
https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ebay.com%2Fitm%2F3CPX1500A7-NEW-RLM-MICROWAVE-Special-Red-Series-Buy-it-NOW-375-World-Ship-65%2F192407593638%3F_trkparms%3Daid%253D222007%2526algo%253DSIM.MBE%2526ao%253D2%2526asc%253D41375%2526meid%253D2f7dd19722d0408dbe76d81dad15c1fb%2526pid%253D100005%2526rk%253D1%2526rkt%253D6%2526sd%253D192407638661%26_trksid%3Dp2047675.c100005.m1851&data=02%7C01%7C%7Cd6f455a3fffb46ca686808d54b3f7210%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C636497658229959105&sdata=d%2FjG52JmHuNtSokNr8Q%2Ba3JLO3GeSj0igUYQQgjTLg0%3D&reserved=0
Hardly $1399.00
73
Jim W7RY
Merry Christmas
-----Original Message-----
From: kstover@ac0h.net
Sent: Sunday, December 24, 2017 8:09 PM
To: 'Bill Turner' ; 'Amps group'
Subject: Re: [Amps] NXP 65V LDMOS 1K80H-1800W
What happens when they quit making tubes?
I can think of one company making a CCS rated tube final amp (Alpha) and
they are hanging on by a thumb nail with their $6K amplifier. The 9500 won't
do CCS RTTY or FM at 1500 watts without auxiliary cooling for the power
supply.
Ameritron amps are not CCS rated, read the manuals. OM Power may be CCS
rated but they use those evil noisy Russian tetrodes. The blowers in these
amps are all famous for sounding like a Bell Jet Ranger lighting up but it's
the noise that SSPA's make that always gets thrown out. Elecraft is testing
a new cooling system for the KPA1500. New fans that turn slower, make less
noise and cool the amp just as well.
Any company producing an SS amp running 1.5Kw out with just one of these
LDMOS devices are idiots.
Everybody but SPE are using two.
I just looked at the price for a new matched pair of RF Parts 3-500ZG's.
$400. A new Eimac 8877 will set you back $1399, a pair of the these LDMOS
devices, depending on dissipation and voltage rating are a push for a pair
new 3-500's. These are all new prices.
The Chinese versions of the tubes are cheaper, about 50% cheaper, but they
could be gone tomorrow depending on which way the wind blows.
Point to all this is SSPA's are the future, like it or not.
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Bill Turner
Sent: Sunday, December 24, 2017 5:16 PM
To: Amps group <amps@contesting.com>
Subject: Re: [Amps] NXP 65V LDMOS 1K80H-1800W
------------ ORIGINAL MESSAGE ------------(may be snipped)
On Sun, 24 Dec 2017 08:49:23 -0800, Jim wrote:
>## I would like to see what both these amp manufacturers have to say
about duty cycle.
>If they are 1.5 kw ICAS, I will pass on em for now, not for the $7K
price tag.
REPLY:
Before anyone gets too enraptured over SS amps, you might want to reconsider
the advantages of tube type amps:
1. With a pi or pi-L tank, no antenna tuner is required up to SWR of about
3:1.
2. Likewise, no low pass filters.
3. Much more resistant to accidental overloads.
4. Heat dissipation is easy.
5. Usually cost less unless you want autotune.
6. 1.5 kW CCS is easily achievable, i.e. a single 8877 pr pair of 3-500Z's.
The most common limiting factor is the power supply, not the tube.
Drawbacks:
1. Warm up time with some tubes. Not an issue with 3-500Z's or other
filament-type tubes.
2. The cheaper ones are all manual tune.
You pays your money and takes your choice.
73, Bill W6WRT
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