[Amps] Why people don't build amps.

Richard Schmuke rdj at wildblue.net
Fri Mar 26 08:08:07 PDT 2010


A week ago I posted a request for help and/or suggestions on my first amp. I
got very few replies but I am thankful for the replies I received.. This is
a very interesting thread so I thought I would try again. I have a
mechanical background but lacking in electrical knowledge. What I have won't
be pretty, It seems this "old" amp was built with parts as light duty as
possible. I have found out with all my "new" parts ( filament transformer,
bigger relays, and tuned input) I will have to move the power supply out of
the amp. My original email follows----------

 Good Day Gentlemen. I have been reading the mail for quite a while. I will
admit I know nothing. I am putting a different tube in a old amp. I have a
workable tank circuit and power supply.  My first question is on the input
circuit.  
How do you do the initial set up?
SWR meter between radio and amp under low power?
 Antenna analyzer with no power at the amp ? Do you need a meter on the
grid? 
If you have time I would appreciate any words of wisdom. The schematic I am
using for the tube is the Zl1axb 600w amp. 
http://www.raibeam.com/zl1axb/813_amp.html
It will be used on 20/17/15m . I will consider it a 20m mono band until I
get the bugs worked out The amp was given to me with a bad tube for work
done, a SB-230. I have the 813,socket and spare and a new filament
transformer. I have moved the tank circuit forward 2.5" and have plenty of
room for the 813.  I am retired and trying to use parts on hand. Is there
somewhere I can read the basic steps of fist light of an amp. I am now
replacing the basic P/S diodes & caps and relays, installing a new plate and
filament choke in the 30 year old amp.
 Rich, Kd0zz



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