Tokyo High Power did it for decades with a pair of 4CX150A/4CX250B and stable as a rock on all bands. As with many amps a homebrew version may not have the best layout and construction practices and
<That seems very low drive for passive grid. The NCL-2000 could use up to <100W in the high drive positon at 50 Ohms and 20-25W into the low drive 100 <Ohm configuration. <Carl sides of the hb 4CX-1
<That seems very low drive for passive grid. The NCL-2000 could use up to <100W in the high drive positon at 50 Ohms and 20-25W into the low drive 100 <Ohm configuration. <Carl sides of the hb 4CX-1
Ok, Now that this discussion has gone on for some time, and everyone has had a opportunity to read various articles, here is the question. Can anyone give me a reason why a cathode driven tetrode wit
Is there any real data published on those caps? Were they designed for RF, pulse, or DC bypassing? If RF what are the current ratings at various frequencies? An example of the wrong cap for the job i
These links were provided for two manufacturers. http://www.nd2x.com/Russ-caps/kbi/kbi-en.html http://www.nd2x.com/Russ-caps/cap-en.htm Click on the blue to expand. Carl -- This email has been checke
Alpha offered a low drive mod for that series of amps, check their legacy amp docs. My 76PA 3 holer will easily run 1800W with100W drive, I back it down for 1200W. Carl To the group: Have a friend wh
As low as required to peak the output at 1200W, about 30-40 ma total with used tubes at 60W or so. I bought this amp as a basket case, bad tubes, transformer, bandswitch, etc, so do not know what it
The tubes are rated at up to 30ma each so you can run them all at 60ma as now until they need replacinrg or a 2 x 3CX800A7 conversion. I tune using the grid current peak only using the Load control t
The SB-220 will show increasing VSWR in bypas with increasing frequency due to the antenna relay having some inductive reactance. A 30-33pf 1000V COG/NPO disc cap will get it down or you can use a mi
I dont even look at the plate current other than see its there. With those drive levels and soft tubes you will never get too much. Carl Carl: Got it. I keep the grid at 60 ma max. But on 40m to get
Here you go, exact fit and Made In The USA https://tinyurl.com/y7tmvweq Carl I recall being offered one a few years ago at Dayton, but don't remember who it was. Both the relative power and HV meteri
The 572A/B arrived in 61 and in the SB-200 in 63 while HRM started in 67. I remember the owner/publisher Skip Tenney plus editor/tech guru Jim Fisk coming to National Radio to scare up some ad revenu
As long as both tubes draw similar idle current there shouldnt be any power hogging. Ive mixed all sorts of configurations including one or two 4-400A's in amps that were true GG. At reduced power yo
If it is like my 76PA 3 holer with the basic EI transformer any generic120VAC muffin fan will work as all it needs to do is move a little air around the PS side. I used one from a scrapped vintage PC
The original B$W 800 plate choke is far from adequate on 160 to start with and causes problems at both ends. The 802 was a bit better and its been awhile since Ive been into those amps so dont know i
Ive used the Ameritron (never paid extra from RFP) as high as ~4KW + SSB/CW in modified LK-800A's using the 3CPX tubes and with the LK-550 transformer. And also 2 holer AL-1500's which was as simple
I hate to break the news to you but I have a few decades more experience building, using, and servicing amps than you can claim so back off on the snotty comments. That includes a couple of commercia
Yes the tank is the same and with the stock transformer there is not that much of a difference in output so the operation is adequate. There is nothing magic about the ARRL Q=12 and a wide variation