dust cap problem resolved

[tubenit]

This is one of the weirdest problems I've run across with an amp.  Fretting the heavy E string on the 5th fret to make an "A" note, would cause the amp to have a paper rattling type noise.  However, simply playing an open A string would NOT produce the noise.  Figure that one out.  It did the same thing on ALL 3 of my electrics so it was not a fret or guitar set up issue.

I am embarrassed to say that I thought at one point it was an electronics issue and I spent a few hrs trying to resolve it that way.  I tried changing tubes and a few caps etc ............. & added some shielded wiring from the PPIMV to the power tubes.  Nothing resolved it.

Turns out about 2 inches of the dust cap/cone  had pulled loose of a fairly new speaker for me.  I've never pushed this speaker really hard and it is an Emminence Delta-Pro 12A which I've really liked.  I used some contact cement and a small artist brush to get inside the opening and then pressed it back shut and put a little flexible glue on the outside seam.  And I "doped" the outer edge of the speaker with the same  Weldwood contact cement.

Issue resolved!  Just thought I'd pass this on.    With respect, Tubenit

[jojokeo]

I've had similar things like this and it's always a tough thing to pin down for sure. I always tend to think parasitics but like with kind of troubleshooting you cannot bypass any steps in the systematic approach process! If you do it will always bite you in the butt and many times it costs a lot of time and sometimes money too. But time is money too.
This is a definite tough one in that the only way to catch it is by unmounting the speaker. And since it's new you would never suspect it to have this kind of issue!?

[marshallguy]

This is one of the weirdest problems I've run across with an amp.  Fretting the heavy E string on the 5th fret to make an "A" note, would cause the amp to have a paper rattling type noise.  However, simply playing an open A string would NOT produce the noise.  Figure that one out.  It did the same thing on ALL 3 of my electrics so it was not a fret or guitar set up issue.

I am embarrassed to say that I thought at one point it was an electronics issue and I spent a few hrs trying to resolve it that way.  I tried changing tubes and a few caps etc ............. & added some shielded wiring from the PPIMV to the power tubes.  Nothing resolved it.

Turns out about 2 inches of the dust cap/cone  had pulled loose of a fairly new speaker for me.  I've never pushed this speaker really hard and it is an Emminence Delta-Pro 12A which I've really liked.  I used some contact cement and a small artist brush to get inside the opening and then pressed it back shut and put a little flexible glue on the outside seam.  And I "doped" the outer edge of the speaker with the same  Weldwood contact cement.

Issue resolved!  Just thought I'd pass this on.    With respect, Tubenit

Geez, I have a 2 by 12 cabinet with 2 of those. Not good. Glad you found it.

[bmccowan]

I have used fabric dope for model airplanes for doping speakers and for layering tissue paper cone repairs.
And I have had that issue where a fretted note, but not the open note, makes a buzz. I don't recall if I figured it out.

[marshallguy]

I have used fabric dope for model airplanes for doping speakers and for layering tissue paper cone repairs.
And I have had that issue where a fretted note, but not the open note, makes a buzz. I don't recall if I figured it out.

I tried the tape, tissues, torque. Nada. Exploring other possibilities. Could be resonance in that spot where I work or some sort of tinnitus from an ear infection (both) I had started in late  May. I’m hearing it now on 3 different speakers and 2 separate amps. I need another set of good ears.

[acheld]

I've had some luck tracking down weird noises with a sound analyzer on my phone.   There are many free ones out there -- I use Sonic Tools on iOS, but not saying it is better than others.

The FFT (fast Fourier transforms -- remember these from calculus days??) function allows you to zero in on the source of the sound.   If you're hearing it with multiple amps, consider the source -- or something in the room.

I hear you on the tinnitus thing -- probably 90% of forum members have this or will get it.  No fun.  I often warn young band members about using hearing protection on stage, and the looks I get are priceless.  LOL, they think I'm just an old fogey, and they'd be ... correct!

[shooter]

FFT

They haunt me at night 
my scope has an FFT feature, you can make a loop antenna and hunt down bothersome stuff.  Called it a sniffer coil in my field.