Home |
Search |
Today's Posts |
#5
![]() |
|||
|
|||
![]()
Gary Schafer wrote:
Hmmm...PP 807's @ same load Z as PP 811A triodes...interesting... It doesn't matter what the actual impedance of the modulator or the final is. It is the ratio that matters. The ART 13 transformer has a primary rated at 15000 ohms and the secondary at 7300 ohms. That is a ratio of about 2:1. The Johnson viking 2 (pair of 1625s modulating a pair of 6146s) used a transformer with a ratio of around 2.4:1 or so if I remember right. That was a little high as the modulators would go into clipping before 100% modulation could be achieved on that rig. A little lower ratio mod transformer would have allowed a little more modulation. So the ART 13 transformer is just about ideal for that kind of setup. 73 Gary K4FMX One small thing, don't go too ape s*** crazy with substitutions. You must understand that for a given wattage transformer core, higher impedance windings will have more turns than lower impedance windings. It wouldn't be ok to sub a 2:1 transformer that was meant for 10K for a 2:1 that was meant for 1K. Not at the design power for the transformer. Why does this matter? Subbing a much higher impedance transformer for a low impedance transformer will result in greater losses due to the higher resistance of the windings. Subbing a low impedance transformer for a much higher impedance transformer will likely result in core saturation and loss problems due to the higher fluxes the core sees. There aren't enough turns on the core. Try find a sub that is close to the design impedance of your desired transformer. -Chuck Harris |
Thread Tools | Search this Thread |
Display Modes | |
|
|
![]() |
||||
Thread | Forum | |||
F.S. 100 ohm 2 watt resistors N.O.S. | Boatanchors | |||
WTB: 100K 2 watt carbon resistors NOS | Boatanchors | |||
WTB: 100K 2 watt carbon resistors NOS | Boatanchors | |||
Help w/ Varian xfmr | Boatanchors | |||
FA: DIAMOND SX 1000 SWR WATT POWER METER *** Ends Today!!! | Antenna |