I have found problems when using high impedance supplies with 6146s, especially as they get older. Especially bad is the Yaesu 'anti flash over diode' in series with the screen grid - any negative sc
Any ideas on what values to use for step start resistors? In the past, I've tended to choose a value from the available stock - something like 50 ohms, 100 watts, which limits the surge current to ju
I didn't make it clear that the 'low impedance' screen supply means low impedance both for source and sink - i.e good regulation for both source and sink.. For 6146B's, I use zeners - not ideal, but
relay stepstart is a less I rather go along with Rich on this one. For HV supplies, I go along with him about the use of thermisters, too, although for filament inrush limiting, that seems a good app
If the IMD products were the mixing of the harmonics, it should be possible to trap them out. Pappenfus et al point out the fallacy of regarding IMDs as being the mixing of the harmonics: it is howev
The 4CX1000 data sheet says it needs cooling air at the same time as the application of heater volts. Frightening to realise that the 4X150/4X250 basic design is older than I am, it being in producti
Soemwhat easier and more controllable is caustic soda (sodium hydroxide). Readily available (or at least was - I wouldn't bet on it still being so with the modern environmental police) for drain clea
The question was asked Not as such. The story I was told from someone who worked at the factory, that a large 275kV transformer ( 100+tons) was tested and the insulation test left a charge on one of
Bill asks: Under what conditions? Class A, grounded grid, about 120 ohms ( in class A grounded grid, Rin = 1/gm) Grounded cathode, 22pF at low frequencies: at HF, cathode lead inductance will modify
Plain bearings are quieter than ball bearings, but generally don't last as long before they start wearing and get noisy. If you can get 'Oilite' sleeved bearings, they last pretty well and don't need
I tried push pull source followers with a 2 turn loop about 1 metre square. Unfortunately, I got about 80 volts rms across the tuned loop, and the source followers departed this life very rapidly....
Don't know about the Thunderbolt specifically, but my experience with the 4-400 and 4-250 family is that 2 to 2.5kV isn't really enough to get more than about 400 to 500 watts PEP out in AB1. Both tu
crimped, I believe they've learned the hard way in the US not to crimp aluminium cables, though........... 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contes
This somewhat puzzles me. I would have expected it to be tuned higher in frequency ( although maybe no more than 0.5 to 1 Hz) so that it looked very inductive under no load conditions. As the load in
with silver solder, I'm not sure exactly what Rich means by 'silver solder' in this context. If he means the high temperature ( 600 - 800 deg C) stuff we use for model steam engine boilers and fittin
matter. That depends on the time delay you need - leakage in a normal electrolytic may be too much if you want a longish delay. Somewhere, I have some MPF121if you really want to try, but I've just g
done. I've seen a number of professional tx's in which it was done. One of them was pretty massive - it had a pair of 813s modulated by a pair, and took two 6 foot high 19 inch wide racks. The main H
In that case, how about the 872? It's a sort of big brother to the 866. But this is one application where I'd go solid state. One problem with big mercury vapour (and even big xenon) rectifiers was t
I thought these days that Pacific G & E (I'm told that's 'Pacific Graft and Extrortion!') was charging so much for electricity that very few could afford to run a 'California kilowatt' any more. 73 P
John Lyles asked: Yes. 73 Peter G3RZP _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps