[Amps] GU-84B Conversion

[Bill Smith]

I'm considering converting my old Swan Mark 1 (two 3-400Z tubes) to use one GU-84B.  Some time ago I replaced the panel bandswitch in the Swan with a Radio Switch Model 86 six position switch with two wafers.  At that time I also replaced the tank coil with one that was made for the National NCL-2000 amplifier.  My new bandswitch required me to rearrange the RF compartment considerably.

The transformer was replaced with a new one from Heyborer in Michigan.  At that time I had them use the next larger diameter wire in the HV and filament windings when they wound it.  The caps, etc. were all replaced with snap in type on a circuit board.

Ok that's the history of the amp to date.  It has a resting plate voltage of 2900vdc and 2500vdc or so under load.

Readings with two 3-400Z tubes:
Plate Current Readings on Operate HV Setting (SSB):
270ma using a Tuning Pulser
Resting Plate Current is 190ma
460ma SSB Peak (Talking in Mic)

Plate Current readings using CW Mode(1500vdc)
Key down 660ma
Resting 80ma
SSB 320ma Peak

My question is will the GU-84B perform satisfactorily with this transformer?  I know I'll need another filament transformer and one for grid voltage.


73,
Bill Smith KO4NR