[AMPS] A look underneath the Ugly amp. chassis.

[measures]

I added a chassis view of the Ugly amp. to my Web site.    Warning.  This 
is a high-res  JPEG file, so it takes a while to download.  However, you 
can pretty much see what's what.  The grid roller coil [from Collins ant. 
tuner/available for $10 from Fair Radio] is just below the grid terminal 
on the socket (center, lower).  The filament transformer is on the upper 
right.  The 0mA grid bias supply is between the socket and the fil. 
trans.  The shiny dark object below the bias supply is the multiplier 
resistor for the 0-10kV anode-potential position on the multimeter.  The 
filament V rheostat is on the lower left.   During the Great Debate, 
there were many stern warnings from critics of "The Nearly Perfect 
Amplifier" (Jan., 1994 *QST*) -  to the effect that manufacturers don't 
use rheostats to control filament voltage (as per the article) because 
rheostats simply do not last in this application.    The rheostat still 
works after a dozen years of service.  

The large shiny surface with four holes on the socket is one of the two 
filament/cathode collets.  The other filament/cathode collet lies just 
behind.  Please note the large collection of multiple-value, HV, disc 
ceramic capacitors that are bypassing both collets.  Multiple disc-cer. 
capacitors are needed because they must bypass 6A-peak of RF to chassis 
gnd over a wide range of frequencies, with little reactance.  .  .  .  
One should keep in mind that above its self-resonant frequency, a 
capacitor looks like an inductor.  For example, your typical 0.01uF 
disc-ceramic universal "bypass" capacitor looks like an inductor on 20m - 
10m.  

cheers

-  Rich..., 805.386.3734, www.vcnet.com/measures.  


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