An interesting explanation of how a MOT compares with other transformers. Thanks Manfred! I guess that microwave oven transformers designers also try to use as little copper as possible, because of i
Again a crystal clear explanation. Thanks again Manfred! So I guess the only remaining option will be to remove the heating winding which is located between the primary and the secondary and replace
I observed the same phenomenon with microwave oven transformers. The core gets very hot when power is applied to the primary even for a few minutes, even with no load on the secondary. This is becaus
Gentlemen, I just bought an old amp that uses 5 PL 519 TV sweep tubes in parallel. As it reads on the box, it was home made on June 1983 by HB9 AWI. The amp does not work anymore, but it is superbly
Dear Felipe, What a coincidence! I just got this quarter-century old amp with obsolete tubes, and almost at the same time, the CQ DL publies an article about a similar design! About the Fuchskreis: T
A very good point Bill! In this particular amp, plenty of room is available for the tank circuit. I will consider replacing the "Fuchskreis" with a Pi or PI-L circuit. But then there is the problem o
Hi Alex, An interesting idea, but since there is plenty of room in the tank circuit compartment of the amp, I think I will first try replacing the Fuchskreis with a pi-circuit, if the anode impedance
Yes, to obtain tha beautiful cherry red glow of the plates :-) a better option would be to increase the plate voltage. With only 600 V from plate to cathode, the cathode current gets too high and the
I see. A sort of push-pull oscillator with the link between the plate of two tubes acting as an inductance. Therefore you try to keep this inductance low by using sheet metal instead of wire. Resonan
Kudos to CQ-DL! I e-mailed them yesterday to buy a copy of the May 2009 issue of CQ-DL Magazine . Instead I found this morning in my mailbox an e-mail with a pdf of the article - no charge! Many than
Dennis, Nice idea to write a book about this subject. What could be more in the ham spirit than to squeeze some industrial surplus (tubes and other things) into ham service? In a TV set, the line out
Commercially available HV fuses are quite expensive. I thought of using a small spring instead, like the ones in ball-point pens. They are about one inch long and could be spread between two isolated
If avoiding saturation is the point, how about using a ferrite rod instead of a toroid? Or using a toroid but cutting a small gap into it (with an abrasive disc)? Angel Vilaseca HB9SLV Radio WC6W a é
Hi, Manfred, You explained why a plate choke wound on a ferrite rod won't be better than one wound on the usual ceramic rod. But on the other hand, a choke wound on a ferrite rod is used as the filam
How about using a string of mains-voltage fuses in series? Has anybody tried this? After all, that is what we do for every component of our HV power supplies: capacitors, diodes, resistors... are all
Just another idea... In the old car ignitions there was a capacitor in parallel between the points. This was made to avoid an arc between the points when the point were switching off 12 Volts into th
how about using a blower from a discarded microwave oven? Angel Vilaseca HB9SLV _______________________________________________ Amps mailing list Amps@contesting.com http://lists.contesting.com/mailm
Hi, I bought a NOS 5CX1500A. I plan to use it in an HF amp. Sockets for this tube are rather scarce. Has someone tried to use it in a home-made fixture? I know, a tube is supposed to be used in the o
There is presently a new Eimac Y-770 / SK-810B Socket (Y770) for 4CX1000A+ for sale. Item 380079009063 I hope $ 699.99 is not the typical price for a SK-840 + SK-806 There's no hurry. I'll shop aroun