[Hammarlund] NOISY FRONT END TUBES

[Magoo]

Anyone contemplating changing front end and mixer tubes in a receiver would 
do well to have a look at the mods suggested for the 75A-4 in the "Collins 
Compendium".  The tubes KM1H suggests are good choices; I changed the 1st RF 
and both mixers in my 75A4 and the result was astounding.  My receiver 
outperforms any boatanchor I have ever used.  The Compendium articles give 
desired voltages to optimize tube operation and so the front end change, at 
any rate, is not simply a drop-in.

Bill, VE3NH