MT15 Noises

Discussion in 'Amplifiers' started by Iqpi, Dec 18, 2018.

  1. Iqpi

    Iqpi New Member

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    Hi all,

    I'm new to this forum because of the MT15 which I received just yesterday.

    First of all: unbelievably great sounds. I love the the cleans and also the high gain sounds. So much fuller and bigger than what I've heard over the last month's even at room-level. (Been through Mesa, Diezel, Laney, and some others)

    But I've discovered things I don't really want to accept. Maybe you have experience with these, maybe I'm just too picky:

    I have (as I believe also many others) noise with nothing plugged in except the cab and standby not switched on. It does not sound like what I'm used to. More like a silent ground loop. It only starts a few seconds after the power switch is flipped. I assume when the tubes get hot. The issues is not that there is something coming out of the cab in general. Also my Jet City 22 which I used until now does have some hiss/hum, but it is by far quieter. I cannot record cleans with the MT 15, as I always heard that electronical noise even while playing. I turned up the volume to around 1/3 and the input gain of the Mic down, but still it was there and too much.

    The other thing is with the fx loop: I have a Zoom G5 which i have used with my Jet City, stand-alone (before using amps) and also with the Laney and Diezel and had no issues. With the MT15 it causes a lot of noise. I assume there's a ground loop, but even with the Ground Lift engaged on the G5 unit it didn't change. I've already ordered a hum eliminator but I can't believe that this is normal. When I bridged the fx loop with just a cable it was fine. Also when I unplugged the G5 from power it was okay. But why would this amp react so different than all of the ones before?

    I've changed preamp tubes one by one without an positive effect. In the end, when I put in V5 in V1 there was even more noise. Switching them back again changed it to the known level. Weird. Explicitly changing them with non MT tubes had no effect.

    I also took out V6 which in the Archon is the Loop and tested it shortly and it seemed like the standard noise was at least less. Still not good.

    But the craziest thing was after swapping the power tubes in their positions (same tubes just left and right change). It caused a LOT of noise as if one of the tubes causes a ground issue. Swapping back brought me back to the known level.

    I've also noticed while starting up several times to test the tubes, that with nothing plugged in some weird sounds we're produced. It sounded like walking with rubber shoes on plastic floor. (Not sure if these are the right words).

    Edit: also biasing it colder reduced the overall amount of noise. I think due to the fact that the general rectification ist less.

    Has anybody had similar issues or any ideas how I could verify if everything's alright with the amp and it's just me or if it is a technical issue?

    Thanks,
    Iqpi

    Btw: it's the 230v model and sorry for any typos. That was a pretty long text to be written on my mobile ;-)
     
  2. BrianC

    BrianC more toys than talent

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    I do not have all of the issues you do. Is it the quietest amp ever - NO. It IS a high gain amp and there is always more noise with that. My gain is dialed down to 9-10 oclock and there is still plenty of gain and it quiets the amp down a bit.
    When I am playing especially with the band it goes away due to relative volume.
    Amps also have a break in period - ???

    My bottom line is that this amp kills for the money, especially with EL 34s in it.;)
     
    X-Mann likes this.
  3. Iqpi

    Iqpi New Member

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    That's what I was saying:
    Killer amp, great sounds and typical high gain waterfall noise when in red channel which is okay :)

    I think mine has issues, as the noise starts in standby. And if I remember correctly, when I first fired this amp up the clean channel was nearly dead silent - now it's unusable. Maybe it's the power tubes. But I'm not really willing to pay 65€ for new ones as it's brand new...
     
  4. Solteroblues

    Solteroblues New Member

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    you need to return it, I believe. Mine is very quiet on the clean channel. The only noise I get is when I turn it to the dirt channel. Also, no loop issues for me.
     
  5. Iqpi

    Iqpi New Member

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    Ah that's a pity!

    Hopefully the next one is better...
     
  6. bodia

    bodia Authorities said.....best leave it.....unsolved

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    I'd say this, as well. I've had mine since the end of June, and it is silent. No issues with noise on the Clean channel at all. I did have HUGE noise when I first got it. Turned out to be a bad patch cable on my pedal board. I know that does not apply here, though.
     
    X-Mann likes this.
  7. LSchefman

    LSchefman Hears Tones

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    You should trade it for the amp in another thread that the OP can’t get a sound out of.
     
  8. X-Mann

    X-Mann New Member

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    I have 2 of these amps & while it’s not a silent amp or a low volume practice amp, it behaves in a way that all of my High Gain tube amps do. My MT15 amp(s) has a small amount of noise that’s now gone in my live rig set-up. There’s an entire thread w/ pictures & video too.

    I run an Ebtech Hum-X on the power cord and have always done this ever since I bought a Carvin Legacy-3 amp. The all metal chassis on the Legacy-3 amp actually created a ground loop w/ the FX unit I was using in the loop. I think there may be a similar thing going on here, but I have no noise in my MT15 set-up.

    I also run a Fractal FX8 in 4CM & use the input noise gate & a post (after the FX Loop) noise gate block. This gives me zero noise at all & I only hear the sweet burning of the Red channels fire Breathing dragon come out.

    Are you pluging-in all your power cords into the same wall socket or plug? If not, this can immediately create a ground loop. Have you moved the amp to other outlets, turned on/off overhead lights & moved computers away? Are you using a noise gate at all? Are you running in 4cm? These are all things to easily check out or look into & can make a big difference.

    Yours may have an issue or your amp might not be responding well to what you’re putting in the loop or possibly your guitar Pickups. The one major thing that I see/hear in a lot of these cases (but maybe not yours), is people trying to play at low volumes with the MT15 amp. In my eyes, it’s not good in this area as it’s a crazy loud amp & in that context, I could see people saying that there’s some white noise.

    There could be a tube issue or maybe a wire cane loose inside......

    Again, I have 2 of these amps and the 2nd one was a demo unit. They are identical, but both were bought new from Sweetwater Sound.

    Where did you get your MT15 amp at? Was it brand new or a demo/used unit?

    Send it back & try another one out & see what happens. I think that’s all you can do here & if the next one acts the same.....then it’s not for you or the gear your using it with......

    I do wish you luck here.

    Peace! X
     
    #8 X-Mann, Dec 20, 2018
    Last edited: Dec 20, 2018
    bodia and goat-n-gitter like this.
  9. Iqpi

    Iqpi New Member

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    Thanks for your replies.

    I found out that the topic is more complex. My G5 actually does have a problem:

    I bought a hum eliminimator. Somehow toegether with that and the Zoom G5 also the electronical noise which blended in the clean channel was gone or less at least. After some recabeling there was a new noise. I cross checked it with my Jet City and the noise was still there: the power adapter of my Zoom G5 is broken and i couldn't fix it. I now ordered a Delay and a Noise Gate which I will try once they arrive (most probably after Christmas).

    Independent of that: The clean-noise level is less than yesterday but still there.

    I also have tried different other things: i connected only the amp to the power outlet: a particular one causes some noise which sounds like connecting and lifting ground very fast. It's on red channel, when the gain ist on a very low level. In another power outlet it's less but not gone. This disappears in the gain-noise when i dial in my preferred level of gain - but still weird to me. Could be the 50hz hum of german electricity. And the cables in this house are from about 1970, which could be part of the issue.

    And yes: it might not be the perfect amp for a low level recording environment. But especially the clean channel noise is also increasing with the volume knob.

    It's really driving me nuts. I want to love this amp and I have waited for it since Feb (2 cancelled preorders, 6 amps ordered in between which i didn't like). And now this might either be a bad one or which would be even worse: it is unusable for my setup.
     
  10. Iqpi

    Iqpi New Member

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    Today i could try another MT15 (different location) and it's the same 50/100hz hum caused by transformers feeding noises into the signal. Found on the internat that this might be caused by bad shielding...
     

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