JMP-1 noise reduction solutions ?

Discussion in 'Amps and Cabs' started by Roodboy, Dec 22, 2005.

  1. Roodboy

    Roodboy Supporting Member

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    I am having some nasty noise issues with my current rack rig which consists of
    1) JMP-1;
    2) Alesis powertrip-8 power conditioner/voltage regulator;
    3) Rocktron Xpression;
    4) Carvin TS-100 power amp.
    All cables for the rig are George L's and the guitar cable to the JMP-1 is Planet waves.
    The problem is at its worst on the high gain channel OD2 of the JMP-1. The noise fluctuates depending on where I am in the room, Its a loud buzzing differen from the single coil hum.
    I get it with a Ibanez RG-570 with Dimarzio Tone Zone/Air Norton/Blue velvet; Ibanez Jem 7DBK with breeds and a bit less 04 LP standard stock.
    I tried different outlets with no improvements.
    From reading posts it doesn't seem to be a ground loop but more like RF noise. I'm thinking if its a ground loop it would be the same noise regardless of JMP-1 channel. I hear it slightly with a Maven Peal Tusk, but nowhere near the same level of annoyingness as the JMP-1 on O-2. I have actually picked up radio stations in the past, but not with this setup.
    Anyway I guess I am asking any input on solutions before I start throwing money blindly at attempting to solve the problem. So here are my questions:
    1) I use the hush on the xpression but it does't really dent this noise so I am thinking about an ISP decimator, but this will solve RF noise, assuming thats the correct diagnosis?
    2) Does it sound like I'm describing a ground loop or RF noise?
    3) Should I get a better power conditioner/voltage regulator?
    Any other suggestions or input would be appreciated.
    Thanks for reading this lenghty post
     
  2. vrdyer

    vrdyer Silver Supporting Member

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    That preamp is a little noisey...inherently. How about an MXR noise gate?
     
  3. Roodboy

    Roodboy Supporting Member

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    I guess I'm hesitant on the noise gate because, I think it may do the same thing as the Hush on the xpression. If i go that route I'm thinking ISP decimator.
    I'ld like to play around with preamp tubes but they are mounted directly to the board in a real flimsy way with these metal guards that spell trouble to me.
     
  4. ericb

    ericb Silver Supporting Member

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    My JMP1 is no more noisy than any of my other hi-gain preamps or amps.. Actually it's pretty high quality and not bad at all. .IF you're using the od2 with other 16 on the volume and over 16 or so on the gain you'll start getting some noise. I've heard nothing but great stuff about the ISP noise reduction units.. I've used various Boss , and Hush stuff , and even hi-end rack stuff in the past and never been satisfied with any noise reduction unit, but haven't tried the ISP (will if I need to tho! ) Good luck

    ERIC
     
  5. Roodboy

    Roodboy Supporting Member

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    Eric, you are absolutley right about the gain/volume settings over 16 =noise. Is the solution isp decimator or better power conditioner?
     
  6. ericb

    ericb Silver Supporting Member

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    hEY THERE, CONTRARY to advice I've read MANY times on this forum , I've never got LESS noise from expensive power conditioners. THen again , that's based on my wiring in Vermont, and the places I've played which are all up here or in Eastern NY. Power Conditioners only seem to reduce noise, if you're use bad power supplies to begin with , or if places are wired bad. I've used up to maybe a 500.00 Tripp Lite . This one and others do keep your LINE VOLTAGE predictable and set at a certain level and that's surely good for not blowing up equipment! FOR NOISE, it's noise gates or living with it. I haven't liked Hush units at all , and haven't like the Boss pedal I owned.. I do have a Boss ns50 (I think that's the name ) 1 of their 1/2 rack series that's better than the others I've tried. I really have to believe some of the posts I've read about the Decimator though as they're from very experienced guys , and guys who use loud hi-gain . I hate spreading heresay without hearing one myself, so still take that part of my recommendation/opinion with a grain of salt

    GOOD LUCK (and if you get an ISP , let ME know if it was worth it!) ;)

    ERIC
     
  7. SteveVHT

    SteveVHT Member

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    I've been using a JMP1 in my main rig for years as well as a backup rig. I've always found the unit to be very quiet for a high gain preamp.
    I also have both ISP Decimators. The Pro rackG and the pedal.I use the Prorack in my main rig, and the pedal for all my other amps and setups. And I can honestly say that after owning just about every "great" noise suppressor, nothing even comes close to the ISP by a long shot. It does not degrade or color your sound, nor does it cut off your notes like 99% of the other units made.
    I did however find that the Rocktron Xpression was quite a noisy unit to begin with compared to other low priced multi FX units. I found the G Major to be much quieter. Not as quiet as an Eventide or G Force, but very good.
    I think what you should do is some standard troubleshooting to find the source of the noise. It could also just be dirty voltage in your house/studio wiring.
    Take the units apart, and start with just the preamp and power amp. Then continue by adding each additional unit with cables till you find the culpret.
    I've also found that if you are going to run the FX with the JMP1, do not use the loop in the JMP1 if possible. It's not the best. It's actually better to run all the units in series. JMP1--->Xpression--->power amp
    Grounding may or may not be the issue, but you will find out if it is during troubleshooting. It is only necessary to have one unit grounded in a rack system. I usually only ground the power amp in most racks I build, and lift all the others. They will all be grounded via the connector cables.
    Let me know if I can help you troubleshoot the system.
    Steve
     
  8. Roodboy

    Roodboy Supporting Member

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    Ok Steve, you convinced me to take it apart and start from square one. I'll do it later tonight. Is the rack decimator worth the extra $ over the pedal version?
    I'm using the Xpression in the loop because I thought this completely eliminates the Xpression from the signal path for dry sound. When I use the Xpression on a preset which completely bypasses the units processing but still physically goes through the unit (#128, I have set to analogue path no Hush no effects), I still hear major tone suck. When I run presets with no effects level from the JMP-1 it sounds so much better to me. When I use the effects I run the effects level on 12 which I think = serial loop.
    Anyway, the noise is really only an issue on the OD2 setting like Eric mentioned with gain/OD over 16. I can tolerate the noise on the clean 1 & 2 and OD1 its much quieter.
    I'll check back in later tonight after I dissassemble/reassemble the rack.
    Sounds like a G-major and/or decimator pedal are in my future.
    Thanks for the suggestions I really aprreciate it.
     
  9. SteveVHT

    SteveVHT Member

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    You may want to invest in a decent mixer to run your effects in parallel.
    Since I did this with my main rig, I'd never go back. You never loose the preampamp to power amp dry sound, and just blend effects in via the mixer.
    Then you can just program a blank patch in the processor for true dry sound.
    I'd suggest the DMC System Mix or similar...
    As for the ISP rack, it is absolutely amazing. The ISP guys are the original guys who invented the Hush units...But now it has what they call Time Vector Processing.
    You run one side of the Prorack into the input of the amp, and the second half in the loop.
    Dead silent with absolutely no tone suckage or cut offs.
    It is controlled by your guitars output and not different presets etc..
    So unlike any other noise gate, you don't have to worry about going from super high gain to quiet clean sounds.... it works perfect for both with no adjustments.
    Over the years I've heard so many inexperienced people saying that racks never sound as good as a head or similar amp. These people are meerly fools that have never played through a properly set up rack.
    I'd also suggest that you get a JJ high gain ECC83(12ax7) and a regular JJ for the preamp. It really wakes up the gain and quiets it down. I'm usually not a fan of JJ tubes, but these seem to work wonders in the JMP1. I put the high gain in V1 and the other in V2 with amazing results.
    Let me know how it goes.
    Steve
     
  10. Roodboy

    Roodboy Supporting Member

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    I dissassembled everyhting and get the buzz even with just the preamp and power amp. I guess that eliminates the Xpression from the equation I even unplugged my refrigerator.
    The preamp has JJ ecc83's I would swap tubes but they are mounted in the flimsiest way I have ever seen directly to the board and with a metal protector.
    I guess I'm looking at the ISP decimator as a solution and its a question of if the $400 rackmount is $300 better than the pedal.
     
  11. Roodboy

    Roodboy Supporting Member

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    I took the plunge on the ISP Prorack G, I'll report back in this thread when it arrives.
     
  12. Roodboy

    Roodboy Supporting Member

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    I got the prorackg yesterday and it swallows noise in the effects loop the problem is I get noise when the Xpressions is bypassed:

    The signal chain runs like this:
    1) Signal path: Guitar >ISP input channel one; ISP output one into JMP-1; JMP-1 effects send > ISP channel 2 input,ISP channel two output > Rocktron Xpression right (mono) input; Xpression R & L output > effects return R & L of JMP-1; JMP-1 R&L output into channel one & two of Carvin TS-100 power amp; Carvin power amp channel 1 & 2 outputs into GFlex 2x12 in stereo. All pow from Alesis powertrip 8.
    2) I get no noise at all running through the JMP-1 effects loop into the Xpression, its so quiet its scary. But if I run dry with no signal into the Xpression I still get a buzz which varies as I move around mainly on hi gain od2 patches.
    I spoke with Buck at ISP, who really understands customer service. he walked me through lifting the ground on the guitar cable.
    It turns out that he thinks there is an issue with the input jack on the JMP-1 because the buzz is present even when the volume of the guitar is rolled off and through the headphone jack of the JMP-1.
    I'll post back after I have it checked out.
     
  13. electronpirate

    electronpirate Member

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    I have NO problems with my Xpression.

    If you're getting single-coil hum, then shield the guitar. Also if you practice in a smallish room, gonna get hum.

    Not sure I buy the 'input jack' thing, since you keep saying you only have problems on od1/2.

    Have you moved/changed tubes in the preamp?

    EP
     
  14. Roodboy

    Roodboy Supporting Member

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    ?

    I just went on a tube swapping binge I tried JJ ecc83s, JJecc803, Tungsram, Mullards and old chinese.
    The single coil hum is absolutely gone.
    It wouldn't bother me if it wasn't dead silent through the loop and the preamp just sounds better to me dry wothout going through a dummy patch in the loop.
    I am going to take the JMP-1 to my tech for a once over, the function knob is a bit twitchy anyway, but I can see myself getting frustrated and going preamp hunting again if it doesn't work out.
     
  15. Roodboy

    Roodboy Supporting Member

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    Problem solved! Channel two of the ISP was only running post preamp through thr Xpression. The noise was preamp generated, and once i ran the ISP post preamp w/o the Xpression it is gone.
    This is one of the best gear purchases I have ever made.
    :dude
     

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