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Bias King

Discussion in 'Amps and Cabs [BG]' started by Jugghaid, Aug 21, 2004.

  1. Jugghaid


    Jun 28, 2002
    Denver, CO, USA
    Is this a good unit? Is the Pro really worth the extra $70? Any tube guys here have any good advice or info for me on these?

    I want to start doing my own work on my heads. I'm not an electronics dolt, I 'm just new to working with these heads and a little out of practice (I used to be a Navy Nuke ET).
  2. A 1 ohm resistor from your grids to ground is a lot cheaper and does the same thing.
  3. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Agreed. I use a cheapie one I got off eBay for 15 bucks, and that's exactly what it is, a 1 ohm resistor in the cathode lead. It sits in little tube socket extender, and there are two wires coming out of it that you can connect to your multimeter. I'm with PBG on this one, when it comes to bias gadgets, the cheaper the better. You can get the ones that have the built in meters and all the fancy features, and some of them have two or four socket extenders that you can use together, but in practice all those things are of marginal value (assuming you already have a decent multimeter).

    You can even build one yourself, go to your local surplus electronics store and get an octal tube socket extender (2 bucks) and a 1 ohm 1 watt precision resistor (another buck), and a couple of banana pin jacks (another buck), and voila, a great little bias gadget. If you're handy with a soldering iron, it's a piece of cake to put together. Or you can save yourself the trouble and spend twenty bucks on eBay. I gotta say, that cheapie bias gadget was one of the best investments I ever made. It gets almost as much use as the multimeter. :)
  4. Passinwind

    Passinwind I Know Nothing Supporting Member Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Another vote for rolling your own. 20 bucks would be the absolute max I could see dropping on one.

    I've seen those extenders make inserting the tube impossible in some amps, so be sure to keep a few resistors around for that situation.
  5. Jugghaid


    Jun 28, 2002
    Denver, CO, USA
    thanks guys
  6. Also, I don't bias using current draw. I set the amp up for maximum clean output using crossover notch and a scope, which is FAR more accurate, because individual disappation of a tube doesn't really tell you anything about what it's doing. You will SEE any crap going on with the output stage on the scope. As long as the tubes are stable ( NOT cherryplating), run them as hot as they will go, regardless of what the 'given spec' for percentage disappation says.