Amp, Tubes or Speakers?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by SubtiltyCypress, Sep 14, 2018.

  1. SubtiltyCypress

    SubtiltyCypress Member

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    Sep 14, 2018
    Hello! First time posting, I need some help with tubes and my setup!


    My setup is a Project Debut Carbon with 2M Blue, to a Jolida JD9 into the Jolida JD 1501 RC with until recently, supposedly GE 5751 Triple Mica Grey Plates, powering Hyperion HPS 738 speakers. All was well and good, until a couple days ago.

    The bass from my speakers started getting, not distorted, but rather cut off, and the notes sounded as if they were in a higher frequency, I am talking electronic music, like Burial and Jon Hopkins. I no longer had that chest pounding bass from the speakers from before, they go down to 35hz and are only about a few months old. Plus, at 90db with 100 watts/channel, it shouldn't be too much power. Though it is usually at 1-2 oclock, but only registers at 85db?

    I bought a cheap Boston Acoustics sub, the Micro90pv 75watts, powered and plugged it into the fixed output of my amp. It doesn't have any detail of the speakers, more one noted, but there is more bass, so it sounds better in that way. I plug out the sub at different times to hear more detail in songs, and there is even less bass from the speakers, even when the sub is not plugged in!

    There is a few pops from playing on my Chromecast randomly, but until that point, it sounded compressed. Then the higher frequency notes started to distort, and I checked the tubes, and one was burned out, so I changed one out with a different kind, and it sounded much better. The distortion of the high end and low end distortion was gone, but I still did not have any of the bass output as before. There still was no punding like before. The lower bass notes were not present.

    Could it be the speakers are blown? Could it be the amp? I bought the subwoofer around the same time I had the issues, so could that be why?

    Also, I changed the tubes in my integrated amp to GE 5751 TRIPLE MICA Black Plates, and it sounded so harsh. No detail and grainy. NOS. I want to buy the same kind I have already, but I cannot find the exact ones. I see multiple kinds of the GE 5751 Triple Mica Greyplates, but not the ones I am using. There is only one picture online and I cannot find anybody selling it or any info on it other than "Holo Getter", and that it is from the 1960s. If the are the same as the other varients, or if anybody else knows let me know, thank you!

    Sorry that was very long :p
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  2. HotBluePlates

    HotBluePlates Member

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    Mar 27, 2017
    The burned out tube was in what? Phono preamp or power amp?

    And are you sure it was "burned out" and not simply not lighting up because it was not fully seated in the socket? I've not had a tube burn open its filament in nearly 30 years of using tube amps. That said, it's always possible there is some problem with the heater power in whichever item had this burned out tube.
     
  3. SubtiltyCypress

    SubtiltyCypress Member

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    Sep 14, 2018
    Sorry, i meant the preamp stage of my integrated amp. The tube's pins were rusted, it was a bit rusted looking inside, and the tube socket was rusted too. Maybe burned out wasnt the right word, but it looked burned in comparison to the other which had none of those attributes.
     
  4. SubtiltyCypress

    SubtiltyCypress Member

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    Sep 14, 2018
    I did not describe it right, I meant it looked rusted. Very brown. Both the tube pins and socket. The right one experienced it a little bit inside too. And preamp tube, the integrated amp has an SS amp stage.
     

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