StratPaulBoogie Posted October 3, 2008 Share Posted October 3, 2008 Hello! I have a Mesa Boogie tube amp with 3 channels. It's a 55-watt w/5 12AX-7 preamp tubes, and 2 6L6 output tubes. I have a problem with crackling noises & lower volume when I turn the master up past 3 o'clock on channels 1, 3, and master output. I bought some contact cleaner and cleaned the pots, and got the same results. Any thoughts on if any of the tubes could be the culprit? Any input is appreciated. Thanks! Insert witty pop culture quote or reference here "_________ Link to comment Share on other sites More sharing options...
picker Posted October 3, 2008 Share Posted October 3, 2008 Contact boogie. They are really helpful with stuff like that. Always remember that you are unique. Just like everyone else. Link to comment Share on other sites More sharing options...
StratPaulBoogie Posted October 3, 2008 Author Share Posted October 3, 2008 That was my next move. Thanks Picker! Insert witty pop culture quote or reference here "_________ Link to comment Share on other sites More sharing options...
Caevan O’Shite Posted October 5, 2008 Share Posted October 5, 2008 Just so you know, contact cleaner can be bad for pots- it cleans without leaving any residual lubricant behind, as tuner-cleaner will. It can actually make them MORE prone to scratchiness. So, it might be a good idea to repeat the pot-cleaning, but with tuner-cleaner (the "regular", "black and white" tuner-cleaner spray is perfectly fine, you don't need to spend any more for the "color tuner-cleaner" spray). Use tuner-cleaner for pots and switches, and use contact-cleaner for circuit-boards and tube-sockets, where you DON'T want the lubricant left behind. I'm gonna guess that your initial problem is due to either component issues or maybe a tube issue; but I recommend that you post your question on the "Feel free to ask Myles"-thread near the top of the forum 'page, and also that you contact Mesa-Boogie like Picker suggested. And please, post back here with what you find out and how things work out for you there! And, best of luck! Ask yourself- What Would Ren and Stimpy Do? ~ Caevan James-Michael Miller-O'Shite ~ _ ___ _ Leprechaun, Esquire _ ___ _ Link to comment Share on other sites More sharing options...
soggybomb Posted October 5, 2008 Share Posted October 5, 2008 have you consulted the manual for your nomad? it probably has info about crackling tubes. Link to comment Share on other sites More sharing options...
Larryz Posted October 6, 2008 Share Posted October 6, 2008 It won't hurt to have the tubes tested...if one of the 6L6's are bad you'll have to buy a matched pair..if any of the 12ax7's are bad you can replace one at a time (or all of them and keep the good ones as spares depending on your pocket book)...if the power tubes (6L6's)are replaced have your amp man check your bias and clean the pots while he's at it...your amp man should be able to find the problem(ie. bad pot,loose wires,trouble shoot electronic parts,clean up circut board,etc.)even if all the tubes are good..this works for me & I hope this proves helpful for you... Take care, Larryz Link to comment Share on other sites More sharing options...
picker Posted October 6, 2008 Share Posted October 6, 2008 That was my next move. Thanks Picker! Let us know how it comes out, dude. Always remember that you are unique. Just like everyone else. Link to comment Share on other sites More sharing options...
Strategery Posted October 6, 2008 Share Posted October 6, 2008 Dewd...bummer. I'd suggest drinking mass quatities. I had a Peavey stereo chorus 400 way back many years ago. At the time, I loved that little combo. Then the chorus went on the fritz. I took it in and had it repaired...but it had this little "tick" based on the chorus timing set. This "tick" could be heard even when the chorus was turned off and would annoy the hell out of you. The amp finally went back to Peavey and 4 months later, even THEY couldn't fix it. They gave me a new amp. Good luck on the repair. Randy "Just play!" Link to comment Share on other sites More sharing options...
miroslav Posted October 6, 2008 Share Posted October 6, 2008 Try removing and cleaning all of the pins on each of your tubes with some contact cleaner...and as you clean each tube...work it in/out of the socket a few times to clean the socket pin holders too. (Don't spray the contact cleaner into the sockets...you'll just end up with a mess inside the chassis.) If that doesn't help...it's deeper...and you need to take it to a tech to check out all your components. miroslav - miroslavmusic.com "Just because it happened to you, it doesn't mean it's important." Link to comment Share on other sites More sharing options...
Caevan O’Shite Posted October 6, 2008 Share Posted October 6, 2008 Good point on not spraying cleaners into sockets, etc., on amps, miro'... Ask yourself- What Would Ren and Stimpy Do? ~ Caevan James-Michael Miller-O'Shite ~ _ ___ _ Leprechaun, Esquire _ ___ _ Link to comment Share on other sites More sharing options...
miroslav Posted October 6, 2008 Share Posted October 6, 2008 I was also wondering...did you actually open the amp and spray inside the pots, StratPaulBoogie...? Some pots are very well sealed...and often there is only a tiny hole where you can get the tip of the long spraying straw into that hole. If you just spray 'em kinda' all over...on the outside...it will do little to clean the actual contacts. miroslav - miroslavmusic.com "Just because it happened to you, it doesn't mean it's important." Link to comment Share on other sites More sharing options...
StratPaulBoogie Posted October 6, 2008 Author Share Posted October 6, 2008 Thanks everyone for the great tips. So far, here's what I have done. I replaced all of the pre-amp tubes (12AX7's) and swapped out the 2 power tubes (6L6's) w/2 known matched tubes of the same model. I cleaned all the pots w/contact cleaner with a mineral oil lubricant from the outside of the amp. I basically sprayed into the small space where the shaft meets the metal casing. In following "Miro's" lead, I may open the amp and spray inside the pots. I'm also gonna contact Boogie. I'm thinkin' at this point if the pots don't solve the problem it's probably on the component/wiring level. Thanks again all for your suggestions. I'll let you know how this turns out. Besides the issues I've listed, this amp is still very usable, and ROCKS!!!! Insert witty pop culture quote or reference here "_________ Link to comment Share on other sites More sharing options...
Shoes Posted October 6, 2008 Share Posted October 6, 2008 1 & 3 must share a single tube, socket and associated circuitry. A schematic would be great right about now. You could, if comfortable with an iron, touch up all the connections. Good luck with that. I still think guitars are like shoes, but louder. Link to comment Share on other sites More sharing options...
Caevan O’Shite Posted October 6, 2008 Share Posted October 6, 2008 I still think that you aughtta run this by Myles (on the "Feel free to ask Myles"-thread), as he probably has a very good idea what few sources would cause these exact symptoms... Ask yourself- What Would Ren and Stimpy Do? ~ Caevan James-Michael Miller-O'Shite ~ _ ___ _ Leprechaun, Esquire _ ___ _ Link to comment Share on other sites More sharing options...
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