somethinng buzzing in my jcm 800

[PelliX]

i dont want to brag but amp was setup with bias by a guy here that fixes all major guitar bands....

[raises eyebrow]

but the moron has such a small room where everything wibrates....

[lowers it again] So the guy is the guitar tech of "all the major bands", but does not have a decent room to test equipment in? He's getting the raw end of the deal there, me thinks. "Hey, Eric, I *think* I've fixed your amp... but I'm not sure. Just take it out for the next gig and lemme know how it went, alright? Ta!"...

i tested the box several times set it to stereo, mono, checked the coil for rubbing, nothing could be detected at all

OK. Have you ordered, bought, crafted, borrowed or stolen a longer speaker cable yet?

 

[paul-e-mann]

i dont want to brag but amp was setup with bias by a guy here that fixes all major guitar bands....but the moron has such a small room where everything wibrates.....and you cant ask him, hey tell me where the buzz is coming from dude...

If you cant figure it out take somewhere else...

 

[bobbyvasco]

Is this a recent issue, did this amp ever not do this? Can you dial this buzz out with your presence and EQ? Open the amp and with a wooden chopstick poke around to see if wires are touching something else and causing vibration. While youre in there check the bias. Also might want try swapping out one tube at a time to see if its a bad tube, use your JVM tubes for the test. Thats all I got Hitler!

so it could be preamp tube or the big one?

 

[paul-e-mann]

so it could be preamp tube or the big one?

At this point in your hands its a process of elimination, rule things out...

 

[PelliX]

so it could be preamp tube or the big one?

Yes.

 

[fitz]

 

[bobbyvasco]

ok so i started the process of elimination.....i took off the jcm 800 head from the 1960 cAB and the buzzing stopped so I guess it is the head...and when I put the head back on, it starts buzzing again
I used a wooden stick to tap on tubes and one sounded little weird soI replaced it and still the buzz is there.....
it seems it si coming from inside the jcm 800

 

[XTRXTR]

Before taking out the chassis make sure all mounting bolts for the chassis are tight, if loose tighten, check for buzz, same goes for any back cover plate screws. Still buzzing? Then take chassis out of cabinet. in the normal sitting upright position test for buzz again. Still buzzing? make sure all knobs and pots are snug/tight to the chassis, take care not to scratch, all jacks are tight? If you find the nut or bolt buzzing then consider using a mild loctite. I still use tooth paste for this kind of thing but its not the best against corrosion.

Cap can clamp bolts, tube holder bolts...

 

[bobbyvasco]

Before taking out the chassis make sure all mounting bolts for the chassis are tight, if loose tighten, check for buzz, same goes for any back cover plate screws. Still buzzing? Then take chassis out of cabinet. in the normal sitting upright position test for buzz again. Still buzzing? make sure all knobs and pots are snug/tight to the chassis, take care not to scratch, all jacks are tight? If you find the nut or bolt buzzing then consider using a mild loctite. I still use tooth paste for this kind of thing but its not the best against corrosion.

i made a mistake...it is in fact 1960 speaker. i separated the head and speaker and the speaker was buzzing a lot still......and I had the speaker send back to thomann...and they found nothing wrong with it....i already checked all the bolts, handles, I opened up the box and I cant see where the buzz comes from

 

[XTRXTR]

Speaker mount bolts, baffle, speaker cab back cover screws, caster mounts, cab input recessed cone mount rivets, cab input jack nut, cab corner protectors rivets, back plate loose?

 

[XTRXTR]

Marshall logo buzzing against the screen

 

[Ronquest]

Post a video of this buzz!

 

[Tatzmann]

My money is on broken speaker if it vibrates a bassnote, heard mainly while playing in lower registers on the guitar, like a G on the sixth string.

Bad speakers do this when the voicecoil is misaligned. I repaired a couple of Celestions with this problem, mainly G12M25.

Press slightly from the back onto the speaker cones, if you feel a rub then you found the problem.

I know you sent it out to Thomann already, but them saying its fine means jackshit.

It is weird that its not occuring with the JVM, i know, but i still say voicecoil-rub.

Yeah, i know my speakerbuzz.

 

[Chris-in-LA]

Isn’t this the same cabinet that was buzzing a year ago?

 

[bobbyvasco]

Isn’t this the same cabinet that was buzzing a year ago?

i sold my vintage one because it was buzzing and bought brand new thinking it will not buzz and it was fine for few months and now it is buzzing and making me nuts....

 

[bobbyvasco]

Post a video of this buzz!

i will do it during weekend....but i don't know if I can capture the exact sound on mobile phone....I will try...

 

[bobbyvasco]

i took apart the amp, took out the reverb tank....no more buzzing lol...so I need to wait for the rubber mounts lol to get it back together

 

[bobbyvasco]

ok seems to me that the reverb is mounted only by 3 screws in other amps too...here is one from reverb 2210 master jcm 800

 

[bobbyvasco]

i finally installed grommets under the screws where the reverb is mounted and the buzz stopped....mucho happy....
tomorrow I will put the amp back together and test it all put together....for now I installed reverb with grommets and it feathering the whole thing so there is no buz contact with wooden housing...

 

[bobbyvasco]

ok here is missing screw