Very strange problem [more to do with JVM amp than effects]

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Drew_TNBDDrew_TNBD Frets: 22445
edited August 2013 in Amps
I hate my current flat for this reason. Regardless of guitar or cables, if I am at home and plug straight into my amp... I get a lot of noise. I mean a LOT. Basically unplayable.

Yet if I plug into my pedalboard and go through the entire chain, the noise is minimal and sounds within normal limits. So I just typically play through my pedals at home, and it's all fine. Here is my board:

image

The whole board, noise is silent. Just wah... noise is back. Just wah+tuner... noise is still there. Wah+tuner+OCD... noise is still there. Wah+tuner+OCD+phaser ... noise is there when the phaser is off, but not there when the phaser is on.

The leads me to believe it is some kind of buffering problem, because AFAIK all of these pedals prior to the Boss delays are true bypass. Pretty much all of my cables are from JohnnyShredFreak. These ones. Patch leads are exactly the same cable, and the REAN jacks. I'm not sure what the cable is. But generally I don't have problems with them... as long as I use my whole chain.

It's annoying, because I often want to put my delays and reverbs into my JVM's loop... and as soon as I do that, and go into the amp from the phaser or just straight from the guitar... noise central, and it becomes unusable. This seems limited to home, I don't get it at the practice room.

Any ideas what the hell can be causing this, and what I should do to fix it? I thought maybe about switching to a TU-3 so I get a buffer at the start of my entire chain. Not sure if that will work, but I clearly have some room.

My Zoom MS-70 CDR should be here soon, but it doesn't have a looper built into it, so I will sometimes still want to use my Boss delays in the loop... so I really wanna solve this if I can.
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Comments

  • ICBMICBM Frets: 71963
    Sounds like it could be some sort of earthing problem - if the amp isn't properly earthed the input can be more prone to picking up interference. A buffered pedal has a low-impedance output which can suppress this. Check the socket you're plugging the amp into - or just use another one and see if the noise goes away. Upstairs flats in older buildings often have problems with improper earthing though.

    Also, is it the JVM you're using? I'm pretty sure these have a 'partially lifted' ground - the audio circuit ground is not directly connected to the mains earth - to prevent ground loop problems, but in some cases this can make things worse for picking up 'static' interference.

    The simplest solution, if it cures it, is just to use a buffered pedal in front of the amp. If you're getting a TU-3 you may be best putting it last before the amp rather than first - try it both ways and see which sounds best. If you put it last just make sure the phaser isn't on while you're tuning :).

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • Drew_TNBDDrew_TNBD Frets: 22445
    Yup!! Upstairs flat here!!

    It's the Joe Satriani JVM, so probably has the partially lifted ground like you say. I think I may replace the Polytune Mini with a TU-3 in this case. Just gives me another buffer to have in the chain for when I move my other pedals to the loop, and I don't use the polyphonic tuning anyway! I'd like to save space, so it seems like just replacing the tuner would be better than getting a dedicated buffer pedal.

    Not sure what you mean by last instead of first - do you mean put the tuner as the last pedal in the chain before it hits the amp; ie.. after the reverb (or phaser when I am putting those other pedals in the loop) ??

    @Digitalscream if you want to buy my Polytune mini, let me know ;)
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  • ICBMICBM Frets: 71963
    Drew_fx said:
    Yup!! Upstairs flat here!!

    Not sure what you mean by last instead of first - do you mean put the tuner as the last pedal in the chain before it hits the amp; ie.. after the reverb (or phaser when I am putting those other pedals in the loop) ??
    Yes - guitar > wah > phaser > tuner > amp. That way you don't have a buffer in front of the wah, which can often affect its tone. It might even with the phaser, although much less likely. With the buffer at the end, you're still buffering the long cable from the board to the amp (ideal on a big stage) which is the biggest source of tone suck unless you have half-bypass pedals.

    Upstairs flats can be a problem - often the earthing is done via the water main, but many mains have been replaced below ground level with plastic pipe now, so the earthing is far less reliable than it was. For most modern purposes it really isn't an issue - not even for safety, since all new distribution units have RCD trips - but 1950s high-impedance guitar technology is an exception :).

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • digitalscreamdigitalscream Frets: 26464
    Drew_fx said:
    @Digitalscream if you want to buy my Polytune mini, let me know ;)
    ZenOvertone beat you to it, buddy ;)
    <space for hire>
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  • Drew_TNBDDrew_TNBD Frets: 22445
    ehehe. No worries. I just picked up a TU-2, once it arrives I'll make sure it solves my issue and then flog the mini in the marketplace I guess!
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  • Drew_TNBDDrew_TNBD Frets: 22445
    Hey IC,

    So I noticed tonight in the rehearsal room that if I plug into the amp directly, the sound is *very* muffled and *very* low-gain. But when I use my pedalboard it sounds fine - no muffling, and regular gain. This is regardless of cables or guitar.

    I also noticed that my clean channel needs to be set absurdly loud - literally cranking the channel volume and the master volume. It doesn't sound "bad" as such, but it worries me that I need that much gain on the amp to even out the levels between clean and distortion.

    Crucially, the distortion (when I am going through the buffers in my pedals) does not seem quiet or under-gained at all, but the clean channel does seem under-gained and quiet - even when everything is cranked. This has been like this (AFAIK) since I retubed around the 20th of July. But I've only just cottoned onto the problem.

    I bought a matched quad of Winged C Svetlana tubes and a range of Golden Dragon ECC83T's, and a couple of EHX 12AX7's. I tried a variety of combinations of tubes in the day today, and they made no difference. The amp is biased to 63mV per-side, which is the same value it was set to from the factory.

    In short - wtf is going on!?!
    :((
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  • Drew_TNBDDrew_TNBD Frets: 22445
    And yeah, it's the Satriani JVM.
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  • photekphotek Frets: 1462
    edited August 2013
    I had the exact problem with my YJM, plug in directly and it was muffled as fook, go in via my pedalboard and it was fine. Marshall said it was a faulty noise gate and repaired it. A week later it happened again which is why I now have a blackstar lol. 

    As for the buzzing noise at your flat, do you have any energy saving lightbulbs? I had some and it caused a nasty interference.
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  • Drew_TNBDDrew_TNBD Frets: 22445
    Hmmm. I'm more worried about the lack of clean volume to be honest. As long as the amp isn't going to kill me, I don't care about plugging in direct.
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  • photekphotek Frets: 1462
    I had another problem associated with this noise gate thing, when i kicked in the boost circuit the volume dropped to a whisper, does the Satch have a boost at all?
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  • Drew_TNBDDrew_TNBD Frets: 22445
    It doesn't no.
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  • Drew_TNBDDrew_TNBD Frets: 22445
    I really hate this shit with valve amps. It's enough to almost make me go digital. But the Satch is literally the best amp I've ever used! Does every sound I want, and is just brutal.

    I'll take it to my tech and get him to check the bias and preamp tubes. If that doesn't sort it, I'll take it up to Marshall and get them to tinker.
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  • ICBMICBM Frets: 71963
    If it sounds muffled straight in and OK with a buffer in front, it sounds like there may be some sort of leakage or partial short in the input section of the amp. That would have to be either the first valve stage - although swapping the preamp valves round should have eliminated that since it's unlikely more than one would have failed in exactly the same way - or the input buffer for the noise gate, which is an IC and is directly coupled to the input.

    That could also produce low volume on the clean channel - it would actually give low gain on the distortion channels too, but it might be less noticeable.

    "Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski

    "Just because I don't care, doesn't mean I don't understand." - Homer Simpson

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  • Drew_TNBDDrew_TNBD Frets: 22445
    I wonder if when opening up the amp I caused this somehow. But I was very careful (making sure I didn't torch my own face off!!) so I'd be surprised. Might just be a basic component failure, but if that is the case... looks like I'm gonna be ampless for a week!
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  • Adam_MDAdam_MD Frets: 3420
    Fingers crossed it's only a week!
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  • digitalscreamdigitalscream Frets: 26464
    Drew_fx said:
    I wonder if when opening up the amp I caused this somehow. But I was very careful (making sure I didn't torch my own face off!!) so I'd be surprised. Might just be a basic component failure, but if that is the case... looks like I'm gonna be ampless for a week!
    If you take a drive up to MK, Marshall might be able to fix it while you wait. There've been a couple of stories of people doing that, and getting a tour while they're there...
    <space for hire>
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  • Drew_TNBDDrew_TNBD Frets: 22445
    Can't drive dude!

    I got in touch with Marshall and they said to get it repaired under warranty it has to go back to the shop I bought it from. Suckage.
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  • Drew_TNBDDrew_TNBD Frets: 22445
    So my tech friend looked at the amp today. He reckons it is quite possibly a dry joint or a leaking/blown coupling capacitor just before the 1st drive stage. The soldering joint on it looked quite suspect. Unfortunately he didn't want to take the amp apart and preferred that I get Marshall to do it via the warranty, which is fair enough I suppose.

    So it's going back to Marshall next week!
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  • I'd get a new amp.

     

    Maybe a Sig X? :))
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  • Drew_TNBDDrew_TNBD Frets: 22445

    =))

    I spoke to Marshall and booked an appointment for the 19th. So gonna cart the amp there on the train! *gulp*
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