[Amps] Price per Watt Conversation

[Jim Thomson]

###  NFB =  Negative feedback.  3 db of NFB means you also reduce the gain 
of the amp by 3 db.  On paper,
to achieve say a 10 db improvement in IMD,  you require 11 db of NFB.

##  6 db of NFB on a SB-220  means you now require quadruple the drive 
power.   NFB will work on a SS amp, since the
gain is sky high  to begin with.

Jim  VE7RF


-----Original Message----- 
From: Catherine James
Sent: Tuesday, April 25, 2017 6:05 AM
To: amps at contesting.com ; W4TVJoe Subich ; Jim Thomson
Subject: Re: [Amps] Price per Watt Conversation

Joe Subich, W4TV <lists at subich.com> wrote:
> Jim Thomson wrote:

>> Baffles me how SS marine xcvrs all have superb IMD...and also run on 
>> 11-15 vdc. Are they using loads of NFB ?

> Yes.  Along with little to no compression and making sure that the IF 
> stages aren't over driven.

Sorry, what is "NFB"?

Be careful with those TLAs. :-)

73,
Cathy
N5WVR