Muzishare X7 - an affordable hand-wired KT88 integrated made at the Line Magnetic factory

Discussion in 'Audio Hardware' started by action pact, Dec 10, 2020.

  1. Andy Saunders

    Andy Saunders Forum Resident

    Location:
    England

    Was it the JJ E83CC by any chance- it is a superb sounding valve.:)
     
    rischa likes this.
  2. rischa

    rischa Where'd Dizzy go?

    Location:
    Madison, WI
    Yep! It sounds great -- in fact, so far I'm preferring it to the RCA 7025 "super 12ax7" I posted a pic of yesterday, which is a bit of a surprise.
     
    Andy Saunders likes this.
  3. h1pst3r88

    h1pst3r88 Forum Resident

    Location:
    Boston, USA
    JJs are great -- been using them in my '63 Vibroverb for years. Not surprised they sound just as good in our hifi tube gear!
     
    rischa likes this.
  4. Andy Saunders

    Andy Saunders Forum Resident

    Location:
    England
    :edthumbs: Have the in my Hybrid amp and phono stage, preferred them to Gold Lions and quite a few other valves, glad it has worked out for you.
     
    rischa likes this.
  5. h1pst3r88

    h1pst3r88 Forum Resident

    Location:
    Boston, USA
    ...now you are making me want to grab the pair I have in my guitar amp and put them in my SET amp!

    Rainy Sunday in Boston... I'll probably do it :edthumbs:
     
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  6. rischa

    rischa Where'd Dizzy go?

    Location:
    Madison, WI
    Been listening to the Gold Lion 12ax7 for the last week. Pretty disappointing so far. Kind of flat and a little harsh. It actually sounded pretty good for the first day or two but then it fell apart. Maybe a case of burn-in for the worse.

    So far the best 12au7's have been the cheapo JJ and the RCA 7025. The 7025 is relatively neutral with good frequency extension and depth, but the JJ adds a little bounce and zip that I quite enjoy.

    I also got some Gold Lion and JJ 12au7's, but haven't had much time to evaluate them on their own.
     
    5-String likes this.
  7. glrydays

    glrydays Active Member

    Location:
    Ottawa, Canada
    My X7 came with the original coupling capacitors (not the new "upgraded" version in the newer builds). I decided to upgrade mine. Based on a recommendation, I went with K40Y-9 0.22uF 1000V Russian Military PIO Capacitors, Purchased from Ebay. (Link below), I was not expecting much..but WOW! For $30 and a little soldering - probably the best bang for buck tweak ever. The bass extension and clarity is quite noticeable. My wife even noticed...! Here is the link:
    Lot of 4 pcs K40Y-9 0.22uF 1000V Russian Military PIO Capacitors New | eBay
     
    Andy Saunders, h1pst3r88 and rischa like this.
  8. Grandpa

    Grandpa Member

    I have received similar positive feedback about these caps in the X7. I'm researching options, sure would like some VCAP ODAMs in there. Love the X7. Tube rolling is a scary addiction that I've recovered from. I have several combos that I like and rotate from time to time. The real improvements are now to be found internally. Cheers.
     
  9. mwmw

    mwmw Well-Known Member

    Location:
    Netherlands
    Hi everyone! New to the forum and tube amps. I've been enjoyed this thread while waiting on my amp from AliExpress to arrive. Just received my x7 and burning it in while sipping some Nikka from the Barrel :) Love the sound so far on my Klipsch rp600m, coming from a 90's Pioneer solid state.

    But not all is sunshine. My right channel is noticably louder than my left one. A decibel meter on my phone confirmed this.
    I switched speakers and tried phono versus DAC input. Both the same result. So it's definitely the amp output.

    Any idea what this can be? Again I'm new to tubes, and quite a noob.

    I biased them all to 40. I did notice that V3 had a higher minimum value when turned all the way down compared to the other tubes. Does that matter? Also, while playing music, when I turn the left knob to V1 or V2, it just jumps to 40. When I turn the right knob, it jumps to max first before stabilizing at 40. Just fyi.

    Hope someone can help me out to balance my outputs!

    Cheers,
    Martijn
     
  10. mwmw

    mwmw Well-Known Member

    Location:
    Netherlands
    Nevermind, rookie mistake :)
    Apparently I switched the 12ax7 with the 12au7. They look identical apart from the print on the glass. Problem solved and it sounds amazing now. Can't imagine what it will sound like after burning in!

    Still, the right meter jumps way more aggressive before leveling out on the bias value, compared to the left meter. But I assume that can do no harm?
     
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  11. rischa

    rischa Where'd Dizzy go?

    Location:
    Madison, WI
    Have you tried switching the KT88's around? If that causes the meter to jump on the other side then you'd know it's probably a bum tube. Just a thought. Good luck solving the issue.
     
  12. rischa

    rischa Where'd Dizzy go?

    Location:
    Madison, WI
    With my Omegas, I've found the X7 bests my Torii Jr above 60 dB or so, but below about 55 dB the Torii takes the edge. 60 db is pretty much the top of my listening range, so that's good news for the Torri. But like I've mentioned, I bought the X7 to drive less efficient speakers, so I think this bodes well.
     
  13. boleiro

    boleiro Member

    Location:
    Salt Lake City
    hey Progrocker, will you please confirm your statement above was that you were running the KT77s on the Muzishare X7??? I see that some people have been using EL34s by biasing them at 30-35ma. Will you please share what you’re biasing the KT77s at? Thank you!!

    I have had my X7 for a year now and have done a lot of tube rolling with the driver tubes and have settled on RCA Black Plate 12AU7s and I go back and forth between an IEC mullard and a Fisher Amperex 12ax7 depending on the music I’m listening to. The sound through my LA Scalas is very awesome. Have only recently started to think about adding EL34s or KT77s to the power section and have different flavors like I do now with the preamp tubes.
     
  14. mwmw

    mwmw Well-Known Member

    Location:
    Netherlands
    Switched them around, 1 with 3, 2 with 4, and it seems like the right meter jumps a bit less aggressively now. But that might be in my head. I should record a video one day and compare.
    Thanks for the suggestion!
     
    rischa likes this.
  15. glrydays

    glrydays Active Member

    Location:
    Ottawa, Canada
    What funtion do the 12AU7's perform compared to the 12ax7? Which impacts sound most?
     
  16. Andy Saunders

    Andy Saunders Forum Resident

    Location:
    England
    Did you try the JJ's Sir?
     

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