The answers I have heard are a resounding 'NO'. These caps aren't designed or intended for the level of ripple current that you get in an amplifiers PSU, and they fail fairly quickly. Usually killing
Another approach to the grid capacity problem is to use a wide band technique. Placing 50 ohm swamp resistor at the grid (assuming you have enough drive power - of the order of 35 watts PEP) and feed
Manfred, great minds think alike! 73 Peter G3RZP Vic, Bill, and all, Instead of a simple plain parallel resonant circuit, which would need to be bandswitched, a simpler solution is to include a basic
Larry, Can you explain what causes a change in input impedance over the cycle when operating in AB1 i.e no grid current? I can see Miller effect causing some change as the amplitude varies, but not o
Larry, Thanks. According to Pappenfus, the change in input capacity in 4CX250B due to variation in electron density between grid and cathode is about 0.1pF, which can cause problems with distortion r
Bill, Agree with your numbers and conclusion. The magnitude of the effects will depend on the swamping resistor. I calculate that at 30 MHz with a 50 ohm swamp, there will be around a 2 degree phase
The 4CX250B is not suitable for use in the classic GG arrangement. Go to http://ahars.com.au/documents/eimac01.pdf for an explanation. 73 Peter G3RZP Hi guys; Anyone can help my with a full detailed
When I was at Marconi's, back in the 1960s, there were marine tranmsitters being made that ran a pair of 4-400 at about 1 kW out. Covered the marine bands from 416 kHz. Obviously, with the antenna lo
This suggests that running in tx with no output at all will kill it even faster. That would not be indicative of a good design. 73 Peter G3RZP _______________________________________________ Amps mai
It just proves Phineas T. was right - yet again. _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
How do you ensure phase matching between the amplifiers? I have often thought of why I do not see the running of multiple HF Tube amps with power combining networks. It would seem that the overall co
There are two things called 'silver solder', and they are very different. There is a 'brazing' type alloy, melting at round 600 to 700 deg C, depending on its exact formulation, and there is a 'soft
The down side to a zener regulator is that the regulation is dependent on dynamic resistance of the zener. GW4FRX found many years ago that zeners were better than VR tubes, but changing to a proper
I too have used MGS - very good people to deal with. Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amp
I agree with Bill, W6WRT. Especially with triodes, if the HV sags a bit, so what? The required plate load impedance won't change that much when the volts go up because the current goes up as well. Pe
One answer that can still be attractive from a cost saving viewpoint is to go and fetch it yourself. I was able to bring my HP tracking generator back from California when retruning from a business t
A variac and a 24 -0- 24 transformer. Check the outputs from each side individually: they should be equal. That tells you the diodes are good (or the same number shorted one each side!) Then a Hi-pot
Once one got above 2 to 3 kW, grounded grid amplifiers started appearing in commercial European transmitters in the 1950s, and especially when drivers of around 7kW became more common, GG amps were u
What is the value of the lowest Q? What harmonic suppression are you aiming for? It should be 43dB + 10 log P, without exceeding 50dB. If there's a tuner on the antenna, that may well mean you don't