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Post by jazzguitar14 on Aug 10, 2008 9:25:24 GMT -7
I picked up some interment crackle and psudo-vibrato thing going on w/ my 28.
Is this a pre-amp / power amp / or rectifier problem?
I assume its the preamp but want to check w/ the experst first (you guys)...
Thanks
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Post by flem on Aug 10, 2008 13:24:10 GMT -7
It could be any of those.
One trick is to put a tiny bit of pressure with a glove or piece of wood or something on each tube to see if one of the tubes is rattling and causing the vibration/crackling. You can also swap out one preamp/rectifier tube at a time. Then try the power tubes in a pair. It could be a loose or worn out tube, especially the rectifier, they get noisy and intermittent when they wear out causing the entire amp to act funny. The EF86 is known to vibrate a bit especially in combos, make sure the retainer clip is secure and there are damper rings on it. If that doesn't fix it check you fuses, speaker connection, if it's a head and cab try a different speaker cable. Check you guitar patch cord, and the jack at the guitar. Are you using any pedals with other patch cords? If all else fails try a different plug on a different circuit breaker in your house.
That's my checklist for odd sounds.
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Post by bluzman on Aug 10, 2008 17:40:19 GMT -7
Keep in mind that if it IS the power tubes, and you change them then you may want to have the bias checked and calibrated.
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Post by bustertheboy on Aug 10, 2008 23:44:20 GMT -7
Then there's the common one that the Doc suggests- see that the amp chassis screws on the top of the head are tight, otherwise you get intermittent earthing/shielding and crackle. Brett
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Post by jazzguitar14 on Aug 11, 2008 6:57:34 GMT -7
Thanks Guys, I did check my signal chain and troubleshoot the simple stuff and there is no problem. Everything is fine with a different amp... Gotta work pretty heavy this week but Ill try to dig into asap and Ill let you all know how things go... Looks like its a good time to order a complete set of glass eithor for fix or backup. $$$ Grrrrrr $$$.
Thanks Again
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Post by bustertheboy on Aug 11, 2008 23:24:48 GMT -7
Do you have any other tubes handy to substitute? Brett
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Post by jazzguitar14 on Aug 21, 2008 5:46:14 GMT -7
After Much troubleshooting I found the problem was simply a loose input jack... LOL...
Oh well, Im happy now and sounding good as ever.
Thanks for the advice everyone. ended up being simple.
BTW, This amp rocks!
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