Larry, have you cleaned the tubes recently? Dust and grime could be blocking the airflow. I clean the 8877s and 3cx800a7s in my station by running them through the dishwasher. 73, Jim w8zr Sent from
Paul, Positive screen current means that current flows into the grid, and negative screen current means that current flows out of the grid. The Zener diode string fixes the screen voltage, with a cur
current flow in current. The a scientist terms of the direction Sorry to disagree with you and Bill,, Gene, but the standard convention for electric current makes a lot of sense, and it's not just t
Ron and Bill and any others interested in this thread, sorry to keep disagreeing with you gentlemen, but I believe your skepticism about "conventional" current is based on a misunderstanding of the c
Hi Jerry, Using a single HV power supply with multiple amplifiers is a bit more difficult than one might at first imagine. Modern amplifier design routes the B- return separately from chassis ground,
Hi Mike, Let me give you the simple, direct answer to your question, and then I will give you the more complicated answer that's closer to being correct. In a vacuum tube, the only things that move b
Hi Gang, I'm finding this a very interesting discussion, since it illustrates how a simple question (how current flows in a vacuum tube) quickly morphs into much more profound issues once the surface
Here's the explanation about how we know gravity waves travel at light speed. First some background. About 1.3 billion years ago, two massive black holes spiraled into each other and collapsed into a
Hi Paul, I believe the detectors were built specifically to detect gravity waves generally, not specifically colliding black holes. The detectors took about half a century to build and debug! When th
That's exactly right, Paul. As I recall, the researchers could locate the black holes as somewhere in the southern hemisphere, but it was just fortuitous that they weren't equidistant from the detect
Joe, both answers are correct. True, you should never "run" the tubes outside their specified range, but merely bringing the filaments up to operating temperature slowly isn't running them! Also, no
$400 is a bargain these days! My last two xfmrs for two homebrew amps (4500VDC and 2700VDC) cost $900 each and weighed 67 lbs. 73, Jim W8ZR Sent from my iPhone _______________________________________
Running multiple RF decks simultaneously from one HV power supply is a bit trickier than it might seem at first, especially if you want individual metering on each RF deck. Grid-driven tetrode amps w
Ahh, we're back on this thread! It's an interesting discussion. Dick's comments, below, are mostly correct about electrons traveling from a heated cathode to the anode. However, electrons don't move
Good question, Dick. The large potential difference between the anode (plate) and cathode results in a strong electric field inside the tube. The lines of electric field start at the plate and end on
I agree with Bill. I've got a K3/P3 and a Flex 6300, and find I'm using the Flex 95% of the time. Once you've used one, there's no going back. Aside from its performance (equal or better than the K3)
I don't think the autotune in the 9500 is oversensitive to impedance variations. It's rather that the optimal tuning point depends on the drive level. If you tune the 9500 with, e.g., 20 Watts of dri
Very good point, Dick. The 9500 accepts 4 antennas per band segment, but the user has to manually select the segment. Jim w8zr Sent from my iPhone _______________________________________________ Amps
Is an updated schematic diagram of the 9500 available, that shows the latest factory changes? 73, Jim W8ZR Sent from my iPhone _______________________________________________ Amps mailing list Amps@c
Are there any disadvantages to using the pulse-rated "800s," on HF over the original 3cx800 tubes, assuming that there's room in the RF deck for the slightly taller envelope? I'd think the higher pla