Massdrop x THX AAA 789

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by neogeosnk, Feb 26, 2018.

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  1. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    yeah me too but is that enough for such an expensive lpsu? I gotta make sure...

    I emailed drop maybe they’ll tell me in 3 weeks when they get to my email ...
     
  2. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I got my new 789 in and the hum is still there which means my old one wasn’t broken.

    So why hasn’t anyone else heard this before? Either you all have shit hearing or my house is full of EMF or nuclear fallout or something.
     
  3. Baten

    Baten Friend

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  4. Sanlitun

    Sanlitun Acquaintance

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    Resisted buying this for a very long time after being stung so many times before by buying products based on measurements and hype (Jotunheim). But the $250 on Black Friday was the correct number.

    Holy shit does this thing have power. I tried my HD800 S with the balanced cable and it far too dynamic and punchy. Constantly fiddling the volume to try and get comfortable, and no play at all with the knob on low gain. Trying it SE today and the results are better.

    I wonder if it's worth returning it or if shipping is prohibitive.
     
    Last edited: Dec 14, 2020
  5. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    God in heaven I can’t imagine using this with the HD800. Yuck. People should only buy this for BA iem use. f**k the measurements. The LCX I’m sure would be a much much much much much much better amp for the hd800.
     
  6. RenEH

    RenEH Acquaintance

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    Would this be a good value upgrade for this amp? I'm reading reports of improved sound quality elsewhere, but I'm really just curious and I'm happy with the way it is right now. I don't even really use IEM's much with it. 80% planars.
     
  7. Sonorus

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  8. Claud

    Claud Living the ORFAS dream

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    No noise from mine. DA611E1E-A418-49B5-8E7C-7448203AB9B4.jpeg
     
  9. Sonorus

    Sonorus Facebook Friend

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    Mine is dead silent with the stock power supply.
     
  10. RenEH

    RenEH Acquaintance

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  11. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I spent 375$ on a Sigma11 LPS and it fixed noise from the stock power supply and made a noticeable improvement to the sound of the amp. Not $375 better but a clear improvement.

    if you don’t hear noise I would say don’t do anything because the Sigma11 LPS is a badass linear power supply and so these other options will likely offer very subtle SQ improvements.
     
  12. RenEH

    RenEH Acquaintance

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    So, surprising I already had a similar mean well PSU from my pi2aes, GST40A24-P1J. A/B testing them I would be hard pressed to hear a difference, but if I had to lean on one with a blacker background, it would be the stock one. Money saved, hurray unless the GST60A24-P1J with more amperage would somehow improve dynamics or something.

    But.. if you have a pi2aes, I want to point out that mean well psu doesn't come with a cable to plug in to the wall. Replacing the one I salvaged from a 80's computer palette two decades ago with something from some random modern electronics did make a noticeable decrease in really high frequency noise. Not something you can hear per se, but something you would subconsouly grit your teeth to. Seriously F this hobby some times.
     
  13. RenEH

    RenEH Acquaintance

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    Was the only improvement noise? No change in anything else like dynamics or sound stage? Are you strictly using IEM's?
     
  14. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I only plug iem’s into the 789 I think it’s a terrible amp for anything else.

    basically everything improved with the Sigma11. But most noticeably a dead black background, dynamics and clarity. Dynamics really improved.

    but not $375 worth. If you are using orthos just buy a better amp.
     
  15. Sonorus

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    Mine with stock ps is dead silent.
     
  16. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    My 3 month old 789 has already developed static when adjusting the volume. What’s worse is that it is super loud through iem’s. I’d send it back but this particular 789 has great channel balance in the pot all the way down to zero. Much better than my previous unit.

    so I’m considering voiding the warranty and hiring someone to put a new pot on it. Tough decision because Drop offers no repair service. So all you get is a replacement if you’re in warranty. So the warranty is particularly important with Drop amps. With Schiit you could always pay for a repair.

    Or maybe they wouldn’t notice I replaced the pot if something terrible happened to it...
     
  17. ergopower

    ergopower Friend

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    If you replace the noisy pot with great channel balance, aren't you taking chances with channel balance still being great with the new pot? Or are you not replacing with same P/N but a higher-quality pot?
     
  18. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Oh it would be an uber pot if I went to all that trouble. Smooth like butter.
     
  19. mk801

    mk801 Almost "Made"

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    Just luck of the draw with whatever crap pot that they grabbed from the bin. My 789 developed this issue one month after its warranty expired. My 3-month old CTH similarly developed this issue too. The fix was pretty easy. Just unscrew the back panel, push out the pcb (from back to front), apply liquid deoxit onto the shaft and try to work it in there by rotating the the glued-on volume knob back and forth. It has been 8-months since I did this for these two amps and the volume pot has been noise-free.
     
  20. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    did you remove all the screws on the back to pull out the PCB? I’ve just removed the 4 corner screws and it ain’t moving. The others seem like they may be holding things in place which may fall off if I unscrew them.

    edit: I removed all the screws even the bottom screw and the back panel came off but the pcb would not budge. I gave up and pointed the deoxit straw as far in as possible aimed directly at the back of the pot and sprayed a bit. Then turned it face down and wiggled the knob for a while. We’ll see if it worked.
     
    Last edited: Mar 29, 2021

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