Randy, Sounds like you need to reduce your loading, which will give you a more pronounced dip. Minimum capacitance on your load capacitor is maximum loading, not minimum loading. So unwind your load
Hi Dick, I believe you're making the hookup of your FT-897D to your ALS-600 seem harder than necessary. First, you don't need the Ameritron interface module at all. A modern solid state amp will alre
I've not been following this discussion in detail, but to me the issue seems pretty straightforward. A black shield around tubes will radiate heat away from the tubes, since the black absorbs radiati
Hi Paul, Yes, if the shield is bonded to the chassis, and as long as the chassis is at a lower temperature than the shield, then there will be a heat flow to the chassis. However, the devil is in the
I've really enjoyed this thread. It's interesting how very practical issues, such as how to cool an SB-220, eventually regress to questions about science and basic physics. That's one of the things t
Kathy, I'd advise replacing the diode string in your SB-200 with 1N4007 diodes instead of 1N5408. Not that there's anything wrong with the 1N5408, but the holes in the circuit board will have to be d
I thought some of you may be interested in seeing a short YouTube video which demonstrates the breadboarded controller circuitry for a high voltage power supply I'm building. The idea is to allow one
\ Irving for discussion following: Rich, I believe the 100mA per device is the quiescent collector current, not the quiescent base current (which is 100mA/hfe=30 ~ 3mA per device). The 27Amps is the
"hard" time? usable, home long times of ** Hi Pat, Theoretically, if you reduced the outside pressure on a glass (or metal) vacuum tube to, say, 1/10 atmospheric pressure, that would reduce the diff
Your explanation about helium defusing because it is inert is correct, and I should have mentioned that. However, the diffusion is also because the atoms are so small, which is why neon, argon, and k
I imagine this has already been mentioned, but with 3-500Z amps, a negative pinning grid current is often an indication of a grid-plate short, or a gassy tube. If there is a conduction path between t
Like many homebrewers, I've always built a timer into my amps that powers the blower for a couple of minutes after killing power to the amplifier. Today, however, in a conversation with another build
Some tubes, such as TH327/347, caution in the data sheet to not run the filament without air flow. In their case, the filament power is about 200 watts. If 200 watts is bad for a tube then it seems l
Hi Ian, You didn't mention modifying the plate choke, but I'm guessing that was an oversight. You'll need one with fewer turns than the original (roughly 10 percent of the inductance), and you'll als
73, Jim Garland W8ZR _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailman/listinfo/amps
I'm designing a dual voltage HV power supply and am ready to order the plate transformer. I'm a bit unsure about the best choice of voltage ratings, however. One primary tap of the transformer would
Alex, this is a familiar problem with nearly all grounded grid amplifiers. Your problem is caused by current from the HV supply leaking to chassis ground rather than returning directly to the B- inpu
I'm looking for suggestions for a source of diode blocks to use in a couple of HV power supplies. I'm using a bridge rectifier and would like to have 8KV-10KV PRV per block. The power supply will be
Over the years, I've had several Advanced Radio Devices autotune linear amplifiers (model 230A uses two 3cx800A7 tubes, model 230AC uses three) and have a substantial number of spare parts I no longe
I'm very surprised to hear this. Here's a counterargument: since the internal filament, cathode, and grid structures of an external anode tube dissipate very little heat, compared to the anode itself