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Tube hybrid for 10m

Discussion in 'Home Brew' started by roggom, Aug 12, 2011.

  1. roggom

    roggom Member

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    I have built tube and hybrids audio amps in the past. I like the hybrids as it is usually the best of both worlds. Robust tubes up front and rock solid SS PA. Does anyone know of some good hybrid plans or links for 10m, something around 100w.


     
  2. ElectronTubesRule

    ElectronTubesRule Active Member

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    Do explain why you would want hybrd? I can understand in an audio amp. Carver (I own many of his amp's) should us how to mimic tube sound by playing with impedance. Trust me I own McIntosh tube amp and all the rest of my stuff is carver,and early Japanese discrete componets before IC Op Amp outputs where they just run amp packs in series with low current........Oh and I recently aguirred a nice vintage tube amp with no name on it....So I understand the sonic difference in tube and most but not all SS amps.

    I have not built any RF amps yet but I have owned tube amps and SS amps and repaired both. I have never run across one that had tube front stage with SS final stage. Not in RF at least. A lot of cheaper tube amps out now the ones that are under $300 and mostly for head phone use often have a tube front end with a ss final output stage.

    SO why would you want to do that in one box for RF though??? I ask because with tubes you have to balance the input very closely for proper efficient output but with SS you normally have a band pass section towards the rear after the bipolar transistors. I am assuming you using bipolars I should not assume that but you still need band pass even with Fet or Mosfet transistors.....So why worry about tuning the front stage and the rear stage in one box. Plus I would imagine the amount of RF leakage in a tube box would get into CMOS devices and all the IC's you might use you would more then likely have to shield the snot out of the SS section because they do not tolerate the type of RF energy in the tank circuits of a tube amp let alone any leakage from the tubes.

    Also since it is the bias that makes most Transistors sound metallic and flat how does putting a tube up front help? Would not the transistor section kill any warmth that the tube added? Asking not telling?

    I have never done what you want to do but I have seen the havoc that RF energy can do to SS devices. I have seen 500watt Splater Box CB'ers open and close garage doors on the "A" channels, turn on automated carwash's, Light up all the lights over head at a gas station that was closed and had it's lights turned off. Even with a nice clean set up filter to town my sweet 16 would cause my Sony Cassette Deck in my car to auto eject the cassette. I have seen peoples car stop running because RF was getting into the CPU of the car. I had a friend that had no power on his Motorcyle CB just a peaked radio so lets say 14 watt's. If he keyed up near a fuel injected Volkswagon Beetle the old one not the modern ones it would shut off that car's Bosch fuel injection.

    So to me it just seems like you would be mixing problems instead of gaining the strengths of the two distinctly different designs.

    If I was going to go that route I would get a 1-2 tube CB Amplifier and I would rework the tuning input circuit which would only be a matter of changing the tank coils and caps maybe the air variables if you needed more variance from end to end in capacitance. I would hook that into my radio and use that to drive my SS amplifier.

    Most CB black market tube amps only need 1.5-3.5 watts of drive from the radio because most of them have a driver section with 1-2 tubes to drive the output tubes.So you could either turn your rigs output way down or build a swamping circuit so you could drive your radio at a higher output level. This would give you tubes driving transistors and two separate box's

    Depending on what transistors you go with ie 12V,24V,50V you could build the SS box to be multi-use as in operate in your car or in your home. Not a hard thing to do it is all in your power supply design.

    I know my way does not properly answer your question but I just wanted to toss out the obvious and play devils advocate.
     

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