crackling noise with my used mark IV

[blazerok]

Hello everyone! i am new in this forum, and i am a proud new mesa boogie user!
i recently purchased a used mark IV short head and a recto cab 2x12. everything seems fine, except for the fact that i hear some pretty loud cracking noise when playing.

-it does that on all channel, no matter if loop or reverb is on or off.
-it is louder on the lead channel, probably because it has more gain.
-the crackling do come from the preamp, since it go through the effects loop(i hear it being processed by delay).
-when i gently knock on the side of the amp, i hear the same crackling noise.
-i tried changing preamp tubes, but i only had 3 new 12ax7 that i could swap in the amp, so i tried them in different sockets, but i couldn't solve the crackling.

I hope someone could help me out. im not sur if the problem come from the tubes
thank you

 

[GD_NC]

Welcome to the Forum. Sorry about your troubles.

Make sure your tubes are seated well and making good connections with the sockets. Take them in and out a couple of times to clean the contacts and/or use some contact cleaner.

Could be a bad switch somewhere, loose connection, dirty sockets or about a million other things. If you have a good amp tech nearby I'd take it in for a checkup and cleaning.

 

[bryan_kilco]

I've had power tubes that were going bad that made a "Crackling" type sound along with noticeable power loss while playing.

I'd say it's most likely a tube issue. Replace all tubes if you got the dough. You never know how old they are when buying a used amp!

 

[blazerok]

thank you for both answers!

i moved the whole setup yesterday to get enough space to look around for the problem while its on, but when i moved it, the crackling stopped! and it has not started over since yesterday. i guess the crackling is gone for now... although i will have to be careful if i have to transport it, since its probably a dirty or bad connection somewhere.

anyway, it is great to get useful info from forum like this!

 

[emperor_black]

Welcome to the forum!

I bought mine about a month or two ago. :mrgreen: Until I read your post, I had forgotten that I used to have the same crackling noise a couple o' weeks ago. Now its gone. I also moved my amp quite a few times (but not when it was turned on). I think the problem was in my guitar cable or jack. I just remembered that I have set a cable for the amp permanently and since then I have not heard the noise. I'm pretty sure its a bad input jack. use a contact cleaner and clean out your input jack.

Sam

 

[blazerok]

thank you for the answer, i will try it if it happens again!

 

[bryan_kilco]

yes, definitely rule out all possible cases of bad cables/jacks before going and taking the amp to a tech. I've experienced many a-problem with this scenario.

 

[MarkIV94]

Guys - I've been running into this same problem for the past year. I've replaced all the tubes, had the amp serviced & cleaned, and still, on a very intermittent basis, I'll get an extreme drop in power, with crackling. All channels, tweed & full power, with guitar plugged directly to amp - no effects loop. Oddly, I've found that switching the amp briefly to standby mode can help solve the problem. Any advice? I'm not that comfortable relying on "flipping the amp on and off to stand by mode" as a long term or permanent solution. Thanks for any help!

 

[jace]

I had the crackling issue before on my mark iv and i tried everything to fix it before taking it to a tech. I had tried new tubes, cleaning sockets, new cables and nothing fixed it. The crackling wasnt always there all the time, sometimes it would be just fine other times it crackled the whole time. The tech ended up finding a broken tube socket, ever since then my amp has had no issues. Not sure if its whats wrong with your amp but it was the issue with mine.