Re: [Amps] Expert 2K

["Paul Christensen" <w9ac@arrl.net>]

I saw the SPE 2K amp at last year's Orlando Hamcation.  Overall build 
quality is excellent -- like the smaller 1K-FA.  SPE has addressed the QSK 
problem that plagued early 1K units although they appear to be using frame 
relays rather than vacuum types.  When the amp is engaged in Tx, the T/R 
relays operate so that the coils are not energized and use the NC contacts. 
This, in attempt to better the relay's activation time instead of using a 
coil accelerator circuit.
I have no issues when using the higher quality frame relays, but my first 
choice is either a vacuum relay or PIN diodes, despite predicted inferior 
lifetime of the vacuums and the care required with PIN design.  SPE was 
considering a vacuum option but I'm not sure that materialized.
Fan noise remains a concern although I believe they're using a high-volume 
solution across the heat sinks.  Output power with my 1K-FA decreases by 
~10% as the PA decks heats up.  Not a big issue but that's an area of 
improvement needed with all commercially made solid-state amps.  Their fault 
circuit design is excellent.  Essentially more than a half-dozen sample 
points are continuously checked and summed.  Any fault immediately 
deactivates MOSFET bias and writes to an error log.
It's nice to have the instant-on power of the 1K-FA but its no substitute 
for a well-designed VT amp.  I'm using a PIN diode "wrap-around" circuit as 
described on my QRZ.com page.
Paul, W9AC


----- Original Message ----- 
From: "Jim Thomson" <jim.thom@telus.net>
To: <amps@contesting.com>
Sent: Monday, March 04, 2013 11:04 AM
Subject: [Amps] Expert 2K


> Interesting in that they list even less specs than the Icom.
>
> Carl
> KM1H
>
>
> ----- Original Message ----- 
> From: "Paul Baldock" <paul@paulbaldock.com>
> To: "Jim Thomson" <jim.thom@telus.net>; <amps@contesting.com>
> Sent: Thursday, February 28, 2013 12:38 PM
> Subject: Re: [Amps] 813 efficiency
>
>
> > Checkout the Expert 2K. Full legal limit even on 6M. A piece of beauty to
> > behold.
> > http://www.expertampsusa.com/ExpertAmps2K.pdf
> >
> > - Paul KW7Y
> ## I was sure that array solutions sold these amps... but not listed.
> How much do these amps cost ?
>
> ##  Being made in italy,  I would be leery of buying into a gong show,
> if problems arose, or warranty work had to be done..or if parts not 
> available
> years down the road.....or if they went outa business. .
>
> ##  I see no IMD specs. What is the imd3 and imd5 ?
>
> later... Jim  VE7RF
>
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