[AMRadio] Ranger Audio... the numbers

Jack Schmidling jack at schmidling.com
Thu Nov 16 23:02:11 EST 2006

I can not do a freq response test because I do not have a proper sig 
gen.  Mine is a cheap step job and the amplitude is all over the place.

I put a 1khz sine wave into an earphone sitting on the mic and measured 
p-p values with a scope....

Pin 2  V7A (grid)........  5mv
Pin 7  V7b (plate)........50 mv
Pin 2  V8 grid............. 3 v
Pin 1  V8 plate..........  40 v
Pin 5  V9/10 grid........  20 v
Pin 3  V9/10 plate.......  10 v  (standby)
Pin 3   """""""""".......  50 v

I assume that where the voltages dropped it had something to do with the 
transformer being across the output and the standby more for the mods.

I all cases, the amplitude dropped a bit and the sine wave got a little 
"bent" when going from stdby to phone.  It flattened out slightly.

In the case of the grids of the mods.. a great deal of distortion was 
seen when in the phone mode. Only an approximation of a sine wave with 
jagged festoons all over.  None of this was seen when looking at the 
plates in the phone mode.

So, what can we make of this?


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