Brad et al-
Thanks for the replies. Lessons learned:
1) A Startpage search is not a Google search!!!
2) This book link is a goldmine:
http://www.pmillett.com/tubebooks/technical_books_online.htm
3) I still am vague on converting the balanced output shown on the "older"
schematics to unbalanced 50 ohm contemporary design.
Any further ideas along these lines? I too am thinking of a push/pull
4cx1500 amp, Brad. I am looking for exceptional linearity.
Charlie N6CFH
-----Original Message-----
From: Brad Osburn [mailto:plantrunner5@msn.com]
Sent: Wednesday, June 17, 2015 3:21 PM
To: Charlie; amps@contesting.com
Subject: Re: [Amps] tetrode push-pull amp schematics
Charlie,
Under the heading of For What it's Worth
I too am building a push-pull amp (4CX1500B). Basically I'm using Rich's
single ended broadband input (4:1 balun xfmr terminated in 200 ohms, 100
either side). Which I have completed and according to my impedance meter,
looks good. I don't care about power just want a clean signal, so I'm
thinking of running class A. I'm down to the tank circuit and I think I'm
going to have a balanced output into my horizontal loop antenna, (600 ohm
ladder line input) thru a 4:1 balun. For a screen supply I'm again using
Rich's zener string off of the plate supply. Generates a whole bunch of
heat thru the dropping resistor, but I think it should prove to be pretty
full proof.
May incorporate the 4:1 balun in my tank circuit by going to a 200 ohm
output, as I said I'm still designing. Found quite a few designs in the 1949
Handbook. I built Rich's balanced tuner and it works well, may incorporate
that in my output as well.
This is my first amp I've designed so I'm just trying for 160-80-40. Using
a 2400 volt control transformer (5kva) for my supply and I took 5VDC linear
supplies and redid the control board to give me the 6V+- out I need for
filaments and so I have a regulated filament supply. Limit inrush to less
than 2X.
For the record Rich said don't do it (band switching). But I've wanted to do
this since HS.
Brad
AB0YD
-----Original Message-----
From: Charlie
Sent: Wednesday, June 17, 2015 12:41 PM
To: amps@contesting.com
Subject: [Amps] tetrode push-pull amp schematics
I am looking for a schematic of a push pull tetrode amp. Any ideas?
Thanks,
Charlie
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