** Interesting dissertation, Bill. What is the explanation for an arc in a near vacuum producting a stentorian Bang outside the envelope? - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, www.vc
** that pretty much describes it, Jos. However, "ambiance" [French, from ambiant, surrounding,] is used mainly to describe decor in restaurants and theatres, not human hair pulls. As to the discussi
there. A ** that's because it doesn't, Bob. The only possible reason is that if the 3 grid caps are fairly small, they increase the grid resonance by a couple of MHz. However, this seemingly makes l
** A directly grounded grid (3-500Z) exhibits a grid resonance that is c. 90MHz. A capacitor-resistor grounded grid resonates at c. 90MHz. Grounded grid amplifiers are essentially neutralized below
** Concurrent with a big bang, the circuit breakers typically trip. Does the gettering process take place when the tube is cold? If it does, can the gettering process take place in the time it takes
** By himself, Joe Funderburg, W6IHA, discovered that gas leakage could be identified by equal current leakage with both polarities, while gold-sputter leakage was polarity dependant. He observed th
Ian -- Please explain how a gassy, shorted 3-500Z is gettered between its removal from an amplifier and its being tested for gas with a high-pot a minute or so later? - R. L. Measures, a.k.a. Rich..
With 1mH, >15A of grid-current is not unlikely. The damage to grid-current meters is from DC current because the needle is bent. In a SB-220, the tank's Tune-C limits the potential to c. 3600V peak
The grid-fil current is virtually zero. A grid-fil short does not burn out the choke. The chokes are 1mH. - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, www.vcnet.com/measures. end
^^ A short in the tube does not blow the choke. I simulated a grid-filament 3-500Z short with a clip lead, and the result was a unspectacular rise in DC anode current. The choke did not implode or b
The trick is to have the scope connected when an event takes place -- which could be once in maybe a year or eight. - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, www.vcnet.com/measures. end
Depends on the filter type, mains Hz, 1 or 3 phase, and the rectifier config. There are some estimation formulae on my Web site for 1-phase. - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, www
I measured the Z of some wirewound types and they exhibited little reactance up to c. 1.5MHz. - R. L. Measures, a.k.a. Rich..., 805.386.3734, AG6K, www.vcnet.com/measures. end
No, Mitch, however a solution is to buy new caps and fasten them to the board with silicone-rubber/RTV. Digi-key carries 500v Panasonic [Matsushita] electrolytics. A bit more C than 100uF each would
** not until someone measures the currents present during the event that preceeds a 3-500Z fil/grid short. So far, the only quantity we can guess at is the >15a it takes to melt #28 Cu in the grid's
** Good point, Jeff. My old "plywood box" 20db amplifier was powered by AG6K-installed #4 Cu unbundled loose wires in the attic running over the master bedroom to the electric mains breaker box on t