803's? What about 805's?

Discussion in 'Amateur Radio' started by W5HRO, Aug 2, 2017.

  1. W5HRO

    W5HRO Administrator

    I wonder like with the old 803 tube boxes if hams ever used 805 boxes to hide their beer bottles as well? Did they sell tallboys back then?

    Just bought a case of the below today :mrgreen:

  2. WQ5Q

    WQ5Q Member

    That looks tasty. I have a real pair of 805's ... they're National Union and I think they are NOS. Been in my junk box forever. I could probably sell them for $$$ to the audio nuts but I hate to part with them.
  3. WD5JKO

    WD5JKO Member

    The 805 is a very nice tube. In a class B P-P audio setup, the transfer characteristic has very low crossover distortion even when biased near cutoff. At one point many years ago I had a P-P cross neutralized RF deck with 8005's and B&W TVL coils. The 8005 is a very good RF tube, but through tuning mistakes, and low emission I had run out of them. I changed to a pair of 572B's (same socket but different filament voltage). The 572B in class C RF worked well, but when plate modulated the positive peaks would compress. A hi mu triode like a 811 or 572B just isn't good in plate modulation service. Rummaging around, I had several pairs of 805's...Hmmmm. The 805's needed a different socket, and the grid-plate capacitance was higher requiring neutralization capacitor change (bigger). WoW! The 805 was a fantastic RF tube! Over time, I changed the plate transformer tap, and boosted the B+ from 1500 to 2000 to 2500 volts. The MAX rating is 1500v. For several years in the early to mid 1980's, I ran 2500v @ 400ma for 1KW DC input. Output was 850 watts, and the 805's showed no color. For modulators, I used a quad of 808's at 2250v B+ (Fair Radio used to sell them for 75 cents). I wish I still had that rig....