[Moon-net] regarding the coming 2x4CX250 Amp
Kim Liljekrans [OZ5IQ]
kim at oz5iq.dk
Fri Nov 7 19:59:24 CET 2008
The Q´s from Jordan regarding his coming 2x4CX250 Amp.
HI Gang / Jordan
RE: I'd like to have 10mA on idle
Its ALL too less !! Stay LINEAR, and this can you only do, by :
Stabilizing the G2 ( and G1 ) voltages ! The G2 IS espicially important !
First of all - why do you want to swich the HV depending on the band you are using ??
You have ONLY to swap the G2 voltage, the the desired purpose./ band operation.
Regarding the current :
Each tube may use 15 -20 mA EACH during normal operation (SSB) .
This MEANS, that a MINIMUM of current flowing in the stab unit for the G2, MUST be LESS than tis value ! - otherwise, your tubes will be driven into unlinearity !
I / we have been running the old K2RIW Amp for mni years, with stabilizing tubes for the G2, becource of the matter that the I G2 may both be positive AND negative ! The last means, that the tubes are pumbing current OUT of the g2 pin, and many persons have realized, that their G2 supply unit, simply burns off !
IF normally ie 25 mA is flowing through the "stabilizing unit" and suddenly the tubes generates / is pumping out " more current - the result might be, that the unit burns off ! / goes unlinear .
The point is :
That you need a Constant voltage, with a ie capability of a constant current flow of ie 30 mA . This will give you, the possibility to use a " part" of the current, to the tubes, but without the voltage rises or drops !
Thats what you need !
I have NOT a solution, with semiconductors, otherwice than a constant consumption of the max current, and with proper capability to handle both negative and positive currents, as f.eks. a a pair of OB2 in series ( 150V stab tubes )
Again, any good solutions ? ways of handling this phemenonema ?
VY 73 de OZ5IQ, Kim and with stabtubes in the old K2RIW Amp now 6M.
Moon-Net posting and subscription instructions are at http://www.nlsa.com/nets/moon-net-help.html
More information about the Moon-net