Subject: RE: [Amps] QRO 2500DX MARK lll 4CX800
<Of course any of these amps when married up with a modern SDR exciter
<running Pure Signal IMD cancellation feedback produce truly
<In the Tx tetrode tube space today there are very few choices to be
## The only modern SDR xcvr for sale on the market right now,
with...Pure signal... is the ANAN 7000 + 8000 xcvrs,
which,imo, are not ready for prime time. Esp judging by the 37 K postings
of various issues..on their yahoo group, that I belong to.
Pure signal will really take ahold when Icom, Yaesu, Kenwood start using
it in their future products.
## Heres my take on tubes Leigh. Why mess with a tetrode in the 1st
place ? Tetrodes offer ZERO
advantages over a high mu GG triode. Heck, you dont require a socket
on some triodes, nor regulated screen supplies, regulated
bias supplies, screen and anode current protection, + compensation on the
input for stray tube C, + neutralization etc, etc.
## A dead simple, single chinese 8877 GG triode amp makes more sense.
2 x 3-500Z is also dead simple..and instant on, no grid current
protection required..perhaps a simple fast 3agc grid fuse at most.
## From a HB perspective, why bother with a complicated mess, like the typ
tetrode ? A simple 3CX-3000F7 requires no socket, instant on,
rebuildable, 5-8 kw pep out..or CCS cxr, and -59db IMD-3. Most hams
will die before the tube does. Moot point, cuz your kids can have it
use it..then pass it on to their kids.
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