[Amps] Price per Watt Conversation

[Jim Thomson]

Date: Sat, 22 Apr 2017 16:53:50 +0000 (UTC)
From: Catherine James <catherine.james at att.net>
To: <amps at contesting.com>, Manfred Mornhinweg <manfred at ludens.cl>
Subject: Re: [Amps] Price per Watt Conversation

Manfred,

   So would it be better to use 4 or or more devices with somewhat lower ratings for linear operation?

   Is there a cheaper option to use simpler heat sinks that don't have to be carefully machine, but push them less hard by spreading the power over a larger number of devices?  What's the practical upper limit of devices that could be used before creating other design problems?

73,
Cathy
N5WVR


##  why not use   4  x  BLF188XR    or    4 x MRFX1K80H ?      Is it even  possible to use 2 x devices in parallel in each half of a push-pull amplifier ?    If it is possible, then the heat could be extracted  over 4 x devices.
The TX imd, with 4 x devices run at 1.5 kw, on paper, should be good, since each device is running at 375 w pep output.   Toss in pre-distortion, and IMD could be reduced further. 

##  As is, I believe the SS amp manufacturers will be using pre-distortion techniques to try and get acceptable IMD  out of fewer devices.  Meanwhile, the pair of devices will still be running too hot.  

##  A 4 x device SS amp, if feasible,  IMO,  would not increase the total cost of the amp  by very much...but the benefits would be huge. 

Jim  VE7RF