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  1. #1

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    Hello all,

    I have a Roland JC 120 that I came by used. Works great, but it has a hiss. When I turn it up to around 2 on either channel, there it is. Does not seem to get louder when I turn up higher, it's kind of an on/off thing. This amp has a Roland speaker on one side, and a Celestion G12 Vintage 30 on the other. I will state categorically that I know absolutely nothing about amps or electronics, for that matter. Just wondering if this is common, if the Celestion might be the culprit, is this something a qualified person could fix easily (cheaply), etc.
    Thanks in advance for any info.

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  3. #2

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    I've owned about five JC amps of different sizes. Everyone of them developed a hiss eventually and some had it from day one. It's almost certainly not the speaker.

  4. #3

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    I have a JC55 with a hissy chorus. One thing I noticed when playing very VERY quietly was below a certain level the chorus would actually turn off. Someone on the gear page with a service manual said that when the output voltage fell below 100mV out of the power amp the chorus would actually turn off. Kind of a noise gate just for the chorus. Take with grains of salt since I havent found a service manual yet for my 55.

  5. #4

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    i played one in a store once and the hiss was unbearable...went with a yamaha g50 instead...it hisses a little, but nothing like that jc120...

  6. #5

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    I played on the JC 120 that was sitting in the studio where I use to rehearse but did'nt notice any hiss. However, I guess this could come from the chorus but can't confim since I don't use it.
    However, the main thing I hate about the JC 120 is the cheesy volume control; it is not progressive and really tricky to adjust (especially while playing).

  7. #6

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    Quote Originally Posted by mambosun
    However, the main thing I hate about the JC 120 is the cheesy volume control; it is not progressive and really tricky to adjust (especially while playing).
    I had this problem with many amps - the volume control has 90% of the volume untill 4 and then the remaining 10% until 10. I think brands do this to make the illusion of a really loud amp on stores... And sometimes volume knobs also add bass or highs as you turn them up. I modded my jazzmaster ultralight to avoid this and I am really really happy.

    About rolands the hiss is such an old complaint that I guess it's about time for them to fix it...

  8. #7

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    Quote Originally Posted by khingdheano
    Hello all,

    I have a Roland JC 120 that I came by used. Works great, but it has a hiss. When I turn it up to around 2 on either channel, there it is. Does not seem to get louder when I turn up higher, it's kind of an on/off thing. This amp has a Roland speaker on one side, and a Celestion G12 Vintage 30 on the other. I will state categorically that I know absolutely nothing about amps or electronics, for that matter. Just wondering if this is common, if the Celestion might be the culprit, is this something a qualified person could fix easily (cheaply), etc.
    Thanks in advance for any info.
    I had a JC-77 (w/two 10" speakers), and it, too, had "the" JC hiss. To my experience, the JC-series amps all have it. I used to walk into the room and hear that I'd forgotten to turn the amp off simply by hearing that low-level hiss! Eh, when you're playing, though, nobody hears the hiss.
    Besides that noise, nice amps for the most part. Loved the chorus.

  9. #8

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    My JC-60 has always hissed a little. I try to ignore it, but it can be annoying.

    I sometimes think about swapping out the JC-60 for a Cube 60 or 80. But I can't help but feel like I'd be stepping down from semi-industrial metal frame to a plastic box. (Anybody have thoughts on how the two compare? Which would you prefer?)

    I wonder if the Jazz Chorus/JC Clean amp model on the Roland Cubes includes a bit of hiss--it might not sound authentically like a JC-120 without it!
    Last edited by Flat; 05-16-2012 at 02:29 AM.

  10. #9
    I appreciate all the responses. Sounds like a common complaint, I'll just have to get used to it. Thanks again1

  11. #10

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    I have a Cube 80XL and have heard the complaints about hiss with Cubes on this forum before, though never experienced it, myself. However, I did notice it for the first time the other night. I usually play clean (JC Clean), but the other night I was playing through one of the mod settings with chorus and delay. I noticed the hiss at that point. I played with the amp to see why it was hissing. I noticed just playing through the mod setting, there was no hiss. Playing thru the mod setting with a little delay produced a slight, almost undetectable hiss. Got rid of the delay and turned up the chorus- slightly more hiss. Turned up the delay and the chorus together and got a lot more hiss. I'm thinking that layering the effects produces more hiss with the chorus contributing most.
    Last edited by zigzag; 05-16-2012 at 11:17 AM.

  12. #11

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    usually hiss comes with sound effects or noise gate...

  13. #12

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    I don't think I've ever heard anything with an analog chorus engaged that didn't have some hiss.

  14. #13

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    I used to own a Fender Princeton Chorus ss amp. I never heard it hiss with any settings. That being the case, I still much prefer my Cube.

  15. #14

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    Funny thing.. just reread Jim's response.. wonder about the "eventually"
    Does that mean there are some that dont hiss?

  16. #15

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    Quote Originally Posted by SamBooka
    Funny thing.. just reread Jim's response.. wonder about the "eventually"
    Does that mean there are some that dont hiss?
    Yes, there are some that don't hiss, and quite a few more that may or may not, but the owner hasn't noticed anything.
    To some, any tiny niggle becomes out of proportion. To others, it's what comes out of the amp when you're playing that matters more. How many older amps had 'hum' problems..? Anyone ever had a tele that would hum..? Is any of that a problem..? To some; yes, to others; not. JC's have been known for this right from the start; it hasn't the same importance to all.

  17. #16

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    I had amps that hummed but my tech was able to eliminate the hum in all cases. The main complaint about the hiss is it seems to be "not repairable". Of course the hiss itself will mean more for some than others.

  18. #17

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    I had a JC-77 which was pretty hissy as well. I ended up replacing it with a Fender 65 Deluxe RI which amazingly had much less hiss.

    Ken

  19. #18

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    Never heard a JC120 that wasn't hissy. Keep playing and you won't hear it.

  20. #19

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    Quote Originally Posted by zigzag
    I have a Cube 80XL and have heard the complaints about hiss with Cubes on this forum before, though never experienced it, myself. However, I did notice it for the first time the other night. I usually play clean (JC Clean), but the other night I was playing through one of the mod settings with chorus and delay. I noticed the hiss at that point. I played with the amp to see why it was hissing. I noticed just playing through the mod setting, there was no hiss. Playing thru the mod setting with a little delay produced a slight, almost undetectable hiss. Got rid of the delay and turned up the chorus- slightly more hiss. Turned up the delay and the chorus together and got a lot more hiss. I'm thinking that layering the effects produces more hiss with the chorus contributing most.
    I think there is a built in noise gate on the 80x. I can hear the hiss for just a moment then it stops after a note has been muted. It is very quickly gone.

  21. #20

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    Quote Originally Posted by barrymclark
    Never heard a JC120 that wasn't hissy. Keep playing and you won't hear it.
    I have one as my main amp for 25 years, and agree. When played at volume you can't hear it and it is more noticeable with the chorus on. That big "cha-chunk when you turn it on bothered me more. But, that's life with a big amp. My little Peavey 40 watt practice amp doesn't do it, but it doesn't have the power either.

  22. #21

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    Quote Originally Posted by lschofield
    I have one as my main amp for 25 years, and agree. When played at volume you can't hear it and it is more noticeable with the chorus on. That big "cha-chunk when you turn it on bothered me more. But, that's life with a big amp. My little Peavey 40 watt practice amp doesn't do it, but it doesn't have the power either.
    I know exactly that cha-chunk. haha.

    I have seen this complaint about JC's on other forums and I was telling a guy at Atlanta Vintage Guitars about what I was seeing because he had a customer complain about the hiss. I told him that every JC I have ever played all did the same thing when powered on: "THUMP.... SHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH......"

    Everybody's sensitivity as to what too loud is varies, but the hiss has never bothered me.
    Last edited by barrymclark; 06-12-2012 at 01:42 PM.

  23. #22

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    Hi all,

    I know this post is old, however there may still be some out there having the hiss issue from the JC-120.

    Please, take a look at how I solved it with great success (hardware modification).




  24. #23

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    Just play louder.

    What they don't tell anyone is that no jc series amp is really a play at home amp.

    The hiss is pretty easy to remove while recording if you have a decent plug in.

  25. #24

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    Agree, however this mod will make the amp significantly more quiet at no cost in sound quality, in my opinion.

    So if this amp is used at home, or in more quiet passages of your playing, I think some people will be more happy with this amp after the mod.

    For me, the hiss drives me crazy, otherwise I find it a very nice amp

  26. #25

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    I’d like to solve the hiss, would you know if this mod of jazzfrogs would work on the JC55?