7591 Power tubes: JJ vs EH?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by DeaconBlues, Apr 24, 2016.

  1. DeaconBlues

    DeaconBlues Member

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    I've tried NOS GE's and JJ's. I hear a lot of good things about the EH 7591's. Supposedly, the EH's have more output than the JJ's, but less than the NOS tubes. But, that is a secondary concern since the JJ's have plenty of output..for my purposes. My main concern is the tonaz.

    Any first hand experience with rolling 7591's?
     
  2. EFK

    EFK Supporting Member

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    At one point I had around 8 or 10 pairs of old stock 7591s that I had picked up at a garage sale in the mid 90s. I ended up using them up for amp builds over the years, and I've also used a few of the JJ tubes not long after they were introduced. Also tried some EH. Honestly, in the same circuits, I could not tell any noticeable difference between the JJ tubes and the old stock tubes. The EH seemed a little different, not sure how to describe it really. Kind of 'flat.' Tell you what though, I had a lot of problems with the JJ tubes in combos and microphony. The combos were shaking the crap out of them. Had the same problem with some of the old stock tubes as well, though. Since these were originally developed as hi-fi tubes for mono blocks and stereo drivers, you might get more relevant information out of the hi-fi guys who of course all have golden ears that can analyze the differences between gnat farts, but then, they're not driving them in any way like a guitar amp will drive them.
     
  3. DeaconBlues

    DeaconBlues Member

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    Thanks, EFK.

    I'm using the 7591's in a Goodsell Black Dog 30 head. I think I prefer the JJ's in this application when compared to the GE NOS tubes. But, I can't really put my finger on why exactly. Perhaps there's just a bit more clarity with the JJ's.
     
  4. slider313

    slider313 Silver Supporting Member

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    Do they bias up the same, or have you measured the current draw of each set?
     
  5. DeaconBlues

    DeaconBlues Member

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    The amp is cathode biased. So, no, I haven't measured and compared the bias values of each set. But, good point, slider.
     
  6. slider313

    slider313 Silver Supporting Member

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    Tung Sol is another option for new 7591's.
     

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