Marshall JVM noise issue

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chevy Z 302
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Hey, i was told to visit here for my jvm need.

I've just got one and its very noisy. Its almost staticy as a tv would have but on od1/od2 modes 2-3 its unbearable. If you stop playing its just so loud that i just cant comprehend marshall putting one out like this.

Any thoughts? I've tried everything from switching cables, guitars, outlets, room position, turning off everything electrical and i just cant get rid of it.

thanks in advance
 
is there any particular thing i should look into when swapping them? Or does it matter where they go? Just trial and error to find where its at.

I ask because theres the one thats covered, one next to the power tubes and 3 up front.

im a bit of a noob when it comes to the technical side of tube amps. I've got a small grasp on it but i dont want to do something stupid that results in something huge going wrong.
 
:|::QBB:
chevy Z 302":4e0fc said:
is there any particular thing i should look into when swapping them? Or does it matter where they go? Just trial and error to find where its at.

I ask because theres the one thats covered, one next to the power tubes and 3 up front.

im a bit of a noob when it comes to the technical side of tube amps. I've got a small grasp on it but i dont want to do something stupid that results in something huge going wrong.
Click to expand...

Ya... just shut it down, get a NEW/GOOD 12AX7 (small) preamp tube and try it in all the sockets until the amp sounds normal. (replace - one at a time)

keith
 
thanks guys, i've swapped em with some jj's (fairly new, they work fine in the engl)

Still same problem. Which slot would the phase inverter be?

I've swapped em around, and i still have this problem. I mean the amp is new it shouldnt be having this kind of issue.
 
Try to use a JJ SP12Ax7 in your V1 slot. These preamp tubes have a special covering and they are used to help tame noise. I had issues with my MarkIV and a JJSP12AX7 took care of it.

other than that if you're using OD1 and 2 in orange or red modes and your gain up past 6 then you're going to get some noise. If you have a noise gate that will also help tame some noise.
 
Yea thats the thing, i've ran the isp with it but even with the isp at 100% threshold, ie you play but nothing comes out because of the gate, it still gets the noise.

Now i just need to get the engl back to where it was, somehow i've mixed up the tubes and now im getting some gritty gain with the clean.

:no:
 
:|::QBB:
chevy Z 302":d74c7 said:
Yea thats the thing, i've ran the isp with it but even with the isp at 100% threshold, ie you play but nothing comes out because of the gate, it still gets the noise.

Now i just need to get the engl back to where it was, somehow i've mixed up the tubes and now im getting some gritty gain with the clean.

:no:
Click to expand...

Something is wrong then. I can play my Boogie MarkIV on the lead channel with gains up on 9 and with an MI-Audio Blues Pro on up high and a Decimator set halfway kills all the noise.

If you got it from a store just return it for another one if you don't feel like swapping crap in and out.
 
Well now the powerball has some issue. I pulled the jj's from it to try in the jvm. The jvm still had the noise and now the pb has this thing where its either clean but hums or its not noisy but the clean channel gets distored if you dig into it.

I've tried all 24 tube position possibilities too.

:aww:

On the JVM, theres 5 12ax7 (ecc-83s) tubes right? If i were to buy new tubes is there any particular ones i should get or try? I just hate to buy new tubes for it already and then have the same problem. As well i hate to buy new tubes for the powerball as they were fairly new themselves.

>Try to use a JJ SP12Ax7 in your V1 slot.
is that the balanced one? How can you tell if the tube is this one? I think i put it in the wrong spot on the pb.

Do you all think i just need to buy new preamp tubes?

One last question, where is the V1 position on the JVM chassis?

thanks alot, i do appreciate it. Hopefully my questions arent to noobish.
 
Here is the deal....

The V1 tube is the one closest to the input and has the metal can on it. Looking at the back of the amp that should be the one on the left. Counting left to right from there will tell you the order of the tubes. V1 and V2 are the gain stages of the amp. Try low noise 7025's in these slots or also try 5751's...both of those tubes are very low noise and a direct swap for a 12AX7. The PI tube is the one in the back next to the power tubes. It is most likely not the cause of your noise issue. V3 and V4 control the tone controls and FX mix respectively. These are most likeley not your issue as well. V1 and V2 are what you should be concentrating on. If replacing those with low noise 12AX7's doesn't do it, send it back. :thumbsup:
 
thank you, i will see what GC has tomorrow and hopefully they'll have something in stock that i can at least buy a new 12ax7 and see what it does. Im going to mess around with the marshall tomorrow. I spent the better part of today messing with the engl.

man this weekend went from great to crap real quick.

I will try swapping the JJ's with the v1 and v2 as well tomorrow.


Is there any particular brand of 7025/5751's that you would recommend?? Or a place to order from. I assume my town wont have any in stock, i'll be lucky if GC has any tubes.
 
there are a couple of posts in jvm410.com addressing hiss/noise issues.

S.
 
I get the feeling I'm going to experience this problem since my house's wiring is total crap.
 
if you have earth connection you should be fine. If you don't, make one through your water pipes.
 
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