[Amps] CTI follow up - miscellaneous ramblings

[COLIN LAMB]

Gas tubes v. solid state regulators:

I am always suspicious of an electronic device that hides the electron
flow.  When the VR tube glows, you know it is doing something.  That is not
the case with solid state regulators.  The same problem applies to ceramic
tubes.  You cannot see if they are on.  

The best of all worlds was the wonderful old 1625 in the ARC-5.  I could
tune them up by tuning for minimum blue gas.  That was important because I
had spent my $3.95 plus shipping for the ARC-5 and had not learned yet that
a pilot lamp could be substituted for a meter.  Later, after acquiring a VR
tube, I learned that it could be put in an RF field and used for tuning
just by holding it near the plate.  And, then a friend told me that a
fluorescent lamp could be placed at the end of the long wire to allow your
ham neighbor to see when you are on the air.  

Solid state devices are fine - but they do not glow.  

I only wish they had a VR-5 and a VR-12.

I did have a chance to examine the CTI amp.  Perhaps they do not use the
most modern circuitry and yes the tube dissipation is less than most other
amps - but there was obviously a lot of pride in the manufacture of these
amps.  They are very well built and should last a long time.  It is easy to
criticize the design and used of these tubes, but they are the same tubes
used by the KWS-1 - and that brings tears to the eyes of Collins lovers. I
wish my home built amps looked as good.  One advantage of these amps over a
wonderful new Alpha is that a ham with minimum test equipment could service
them himself using inexpensive components. 

Would the amplifier have brought the same questions and challenges if it
had a Collins label on it?

The 4CX250 tube is not known for great imd performance.  The Collins rig
used feedback to improve the bottom line.  The CTI picks up some
performance using cathode drive, since that will add degeneration.  And,
even though it does not use a tuned input, I believe the 3rd order
distortion level would be close to or below -30db.  Maybe that is good
enough.  

So, maybe CTI overstates the qualities of their amp.  Most things are
overstated.  My truck is not quite as perfect as the television ads.  As a
matter of fact, my wife tells me that I am not quite as good a package as I
touted myself to be or as I think I am.  Nevertheless, she has kept me
around.  Perhaps it is because I installed a lighting system in the house
that no one else understands or can repair.

73,  Colin K7FM