MP2 weird noise...

[rnolan]

Hey Kim, see my earlier post re my MP2 values, e.g. MP2 #3 had noise mod but not R913 and measured 194.8 and was noisy.  I replaced R913 and it measured 189.9 and noise reduced.  Seems you want to be as close to 190 as you can but not more and slightly less is better ?

[vansinn]

@MJMP: Do you think a thin film [R913] resistor would created less noise?
Those do produce less spot noise, but whether this will matter in a HT plate regulator circuitry is :dunno: to me..

[Kim]

Ok, I should just go ahead and replace that R913 then, correct? 

[MarshallJMP]

As for noise don't think it will matter a lot.

@Kim,well maybe best you replace it.

[Kim]

Now we're getting somewhere. 

Tonight I did some more troubleshooting at rehearsal.  It's not the guitar, or cables.  Not even the preamp or fx processor for that matter.
The one thing in my rack that I couldn't check at home....the MT200.   :facepalm:   So I found that if I lowered the Presence on the MT200 to 0, the strange noise following a palm mute went away.  And raising that Presence all the way up resulted in that strange noise becoming a real squeal.   Must be bad tube(s) in the MT200, so I'll swap them out next rehearsal. 

[Kim]

Update:   different tubes swapped in the MT200 changed nothing.  More troubleshooting......So I checked my pedals (that I didn't bring home with me last time)  ::)  and there it was. Taking one pedal out of the equation cleared it up.  I'll deal with that over this weekend.

Really glad it's not the ADA stuff, but I will still change out that resistor that went a bit out of spec anyway.   Thanks for the help!  :wave: 

[rnolan]

Hey Kim, cool, glad you found the issue, which pedal was it ?

[Kim]

Hey Kim, cool, glad you found the issue, which pedal was it ?

Well, when I took the Mel9 out of the chain at rehearsal the funny business stopped.  But....here I am trying to replicate the problem at home again and coming up empty.  This is starting to really get on my tits here.   I brought all the pedals home and ran into both the QuadTube and the Crate G60XL with no problems.  FFS I can't keep dragging ALL my gear home and back to rehearsal, rinse and repeat twice a week.

Maybe some kind of electrical loop?  I have the Crate, Mel9 adaptor, and the Quadtube all plugged into the same power strip here at home.
At rehearsal the Mel9 adaptor is plugged into a power strip that is not shared with my rack gear.
Stan video'd the problem; if he'd send that to me or upload it somewhere I could show you guys what's going on.   

[Kim]

Here's the vid.
https://www.dropbox.com/s/b5xwhznxqnnbziv/VIDEO0082.mp4?dl=0

You can hear that noise just before the Reverb tails. 

[MarshallJMP]

I wanted to open it and I had to ask permission to look at it?? Is this normal?

[Kim]

I wanted to open it and I had to ask permission to look at it?? Is this normal?

Sorry I posted wrong link.  Try it now.    :)

[MarshallJMP]

Ok got permission so ...  :lol:

[Kim]

What do you make of that?  Could be just that resistor out of spec?  I'm ordering some new ones this weekend...

[MarshallJMP]

It's hard to hear ,I hear something but it's very short.So go ahead and replace the resistor and see what happends. It will go in value anyway so at some point you will have to change it.

[Kim]

New resistors arrived today.   :whoohoo!:

Funny though...the 240k ohm 1/2 watt ones are the same physical size as the 3Mohm 1/4 watt ones. The package says they are 1/2 watt though.

I'll bring my rack home tomorrow night so sometime this weekend I'll get on that.