Theory: ultralinear

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by smolder, Feb 29, 2012.

  1. smolder

    smolder Gold Supporting Member

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    Whats the differential in using ultralinear transformers? The late sf fenders get a bad rapp for them, other amp designers have made them work. Is this a simple progression of figuring things out? If its a way complicated question let me know... I've searching for a simple not super technical answer, but can't seem to find it. Thnx.
     
  2. guitarcapo

    guitarcapo Senior Member

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    Based on what I read, it was one of those hi-fi ideas that didn't lend itself well to guitar amplification
     
  3. phsyconoodler

    phsyconoodler Member

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    Leave the negative feedback off and they work great.They add their own negative feedback so why have more unless you want super loud and clean.
     
  4. midnightlaundry

    midnightlaundry Member

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    I modded a Crate V30 and put an UL transformer on it. Ultra Linear was to polite. Regular pentode has the rawness that works for guitar. If UL was so good, everyone would be using it.
     
  5. Blue Strat

    Blue Strat Member

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    Some guys actually like this. Great pedal platforms.
     
  6. vibrostrat43

    vibrostrat43 Supporting Member

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    In my opinion they work well in the Dr Z amps that have them like the Route 66, KT45, SRZ-65, and Delta 88.

    They don't like any global negative feedback, and according to Zaite they just don't seem to work well with beam power tetrodes (which include 6v6's, 6l6's, and el84's), but seem to work fine for pentodes and kinkless tetrodes.
     
  7. pdf64

    pdf64 Member

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    Overdriven UL combined with a high, stiff B+ (eg late 70s Fenders) can result in the screens taking a beating. Sylvania STR387 could take it and folks report that some current production tubes can too. My experience is that Winged C 6L6GC don't last long in those conditions.
    DrZ advises a saggy B+ and KT series tubes for UL arrangements.
    Pete.
     
  8. WesKuhnley

    WesKuhnley Member

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    UL is just one of a myriad of configurations that yields very specific results. It's neither good or bad by itself, a designer must know what type of performance he wants out of an amp, and utilize the proper topologies and parameters to do so.
     
  9. donnyjaguar

    donnyjaguar Member

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    Ultralinear is supposed to combine the best characteristics of Pentode operation with those of Triode operation. Pentode is more powerful than triode and triode is more linear than pentode. Triode also has lower output impedance which results in higher damping factor which can drive loudspeakers more accurately. Ultralinear falls somewhere between these two. This is why, all things equal, Ultralinear has lower output than pentode but more than triode. I personally consider ultralinear much better suited to hi-fi sound reproduction than music production.
     
  10. donnyjaguar

    donnyjaguar Member

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    I can believe this. At idle the screen grids on ultralinear are at higher voltage than the plates. At full conduction, they are much higher.
     

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