#1
So in the last few weeks my Blues Jr. has developed a crackling noise. There isn't any hum or oscillation or anything like that. I'm not sure how to describe it...

You know how sometimes when you move around long runs of cable it is audible through the amp as crackling or thumping noises? Well it sounds like that except without the thumping, and I'm not moving anything at all. The noise comes and goes.

A few times I thought that I was able to trigger the sound by moving a power chord for a PP2+ around. The chord was near the amp but wasn't even plugged into the PP2+ unit. I think it was plugged into the same power strip that the amp is running on though. So I'm wondering if this could be a power thing. It seems like noise issues with pedals and amps often turn out to be power related. I did unplug everything but just the amp and plugged the guitar straight in and still got the noise. I did not move all of my pedals and chords and power supplies away from the amp, but everything was definitely unplugged.

I'm not certain about this, but I believe it is also worse when I have the Master Volume cranked up. I will check tomorrow as it's 1 AM here now. But yeah I think it is worse when I have the Master at 12 (not o'clock) than if I roll the Master back to like 4 and turn the Gain up to increase volume.

So any ideas? Any procedures I need to go through to try to isolate the problem? Thanks!
#2
ummm, crackles. did you try wiggling the input jack?

also check for a loose/lifted solder pad on the tube socket. i've heard those things crack sometimes. and the filter caps. fender has bad reputation with their filter caps, i think illinois caps, they start to blow some goop from the + side of the cap. it's pretty ugly looking. haha
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#3
a cracking noise cab be something with the input jack (as mentioned), the supply caps (as mentioned), or the tubes, whether it be the connection (as mentioned) or the tubes themselves.

typically interference will be in the form of a detectable hum mot an actual crackling.
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#5
Thanks for the responses. I will see if I can isolate the problem to the input jack or tube sockets. I'll also check for leaky caps.

I'm also wondering if I do just need to replace the tubes. Can anybody else confirm that failing preamp tubes can cause crackling noises? Or power amp tubes. I believe the amp still has the original preamp tubes. The power tubes have been replaced with JJs but I don't know how long ago. I'm not sure how old the amp is so I have no idea how old those original preamp tubes are.

I checked the caps when I bought the amp used. I had read somewhere about these amps being notorious for leaky caps. They were fine when I bought it, but I'll have another look!
Last edited by jimtaka at May 21, 2010,
#6
It's definitely something to do with the preamp tubes. On my DeVille I would sometimes get this problem when they came loose after rough travel but usually they needed to be replaced.
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#7
OK so if I decide that I need to replace the tubes, I'm just going to go ahead and replace them all so that I will at least know how old they are. I'm looking at the Eurotubes page. Do the gold pin tubes really make a difference? Are they worth the extra coin?
#9
It depends on the brand. Some brands test their gold pin tubes to higher tolerance but most tube stores do that anyway so the difference is largely negated.
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#10
So have you guys tried gold pins and found there is no difference or slight difference, or are we speculating?

I'm looking at JJ tubes from Eurotubes. It doesn't say anything about the gold pin tubes being tested any harder. It say that the gold pins are "a little richer and smoother sounding."
Last edited by jimtaka at May 21, 2010,
#12
if ur looking for richer and smoother in a 12AX7 position, check out JAN Phillips NOS 5751 for like $25 at tubedepot.com
Call me "Shot".

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#13
have you moved the amp much? maybe just try re-seating them. that may fix the issue straight away.
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#14
Quote by jimtaka
So have you guys tried gold pins and found there is no difference or slight difference, or are we speculating?

I'm looking at JJ tubes from Eurotubes. It doesn't say anything about the gold pin tubes being tested any harder. It say that the gold pins are "a little richer and smoother sounding."


No there's no difference like that. I ordered a set to try them out 2 years back and they sounded the same as the regular JJs I already had in my DeVille. Skip em.
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