Members itstartsstoppin Posted May 3, 2006 Members Share Posted May 3, 2006 I have a mesa nomad 100. Tonight at pratice it just cut out. The power and everything was still on but the sound cut out then came back like 10 seconds later. It kept on doing this every 10-15 seconds or so. The Chord going from the back of the amp to the speakers seemed to be in tact. Is this a speaker or tube problem. Also i should add i am 100% sure its the amp because i tried it with just a cable into the amp and held my fingers on the tip of the cable and then the buzz would cut out. I also tried several differant cables. Link to comment Share on other sites More sharing options...
Members hbar Posted May 3, 2006 Members Share Posted May 3, 2006 Take the cord out of the tact and see if the problem persists. Link to comment Share on other sites More sharing options...
Members AmpliFIRE Posted May 3, 2006 Members Share Posted May 3, 2006 Sounds like you got a bad power amp tube... Link to comment Share on other sites More sharing options...
Members itstartsstoppin Posted May 3, 2006 Author Members Share Posted May 3, 2006 Originally posted by hbar Take the cord out of the tact and see if the problem persists. i did:( Link to comment Share on other sites More sharing options...
Members itstartsstoppin Posted May 3, 2006 Author Members Share Posted May 3, 2006 Originally posted by AmpliFIRE Sounds like you got a bad power amp tube... Sorry to ask a stupid question but the power tubes are the smaller ones right? If thats the problems about how much is it gonna cost me to replace? Link to comment Share on other sites More sharing options...
Members tigger_ferret Posted May 3, 2006 Members Share Posted May 3, 2006 no the power tubes are the bigger ones, probably four of them (if it is 100watts) and they are probably 6L6'stry www.dougstubes.com they are pretty good.Usually you should also rebias your amp after you change your power tubes so you may want to get a tech to look at it anyway. Perhaps even before you buy tubes (they should be able to tell you if you need new ones and which ones to replace)Secondly you shouldn't run your amp with no load to it (ie no speakers connected) this can be very bad for your output tranny and be expensive to replace.If you want to test if it is the speakers connect them to another amp rather than trying to test out your amp without speakers Link to comment Share on other sites More sharing options...
Members itstartsstoppin Posted May 3, 2006 Author Members Share Posted May 3, 2006 Originally posted by tigger_ferret no the power tubes are the bigger ones, probably four of them (if it is 100watts) and they are probably 6L6's yup theres 4 6l6's. So i should expect it to cost about $100 for new ones? Link to comment Share on other sites More sharing options...
Members AmpliFIRE Posted May 3, 2006 Members Share Posted May 3, 2006 your Nomad is fixed Bias (like all boogies). Just buy a new quad and swap out the old ones. Dougs tubes is a great place as is Lord Valve.... Link to comment Share on other sites More sharing options...
Members itstartsstoppin Posted May 3, 2006 Author Members Share Posted May 3, 2006 cool, thanks so much for the info guys. Which tubes would you suggest, i am very happy with the mesa ones that came in the amp, so anything close to that would be great. Link to comment Share on other sites More sharing options...
Members tigger_ferret Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by AmpliFIRE your Nomad is fixed Bias (like all boogies). Just buy a new quad and swap out the old ones. Dougs tubes is a great place as is Lord Valve.... most amps are fixed biased, isn't it just that Mesa has them biased pretty cold and doesn't put in a pot to adjust the bias easily??? I have heard storys of people adjusting the bias in boogies and having a big improvement in tone. That said I haven't actually owned a boogie and I have also heard story's that if you take it to a Mesa tech they are told not to rebias and to only replace the tube that has gone bad rather than all of them. So more than likely you will be fine just pulling the old ones and putting in a new quad. As for which tubes the JJ's always seem to get good reviews but in the past I have used Svetlanas and always like them Link to comment Share on other sites More sharing options...
Members L6Sguy Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by tigger_ferret most amps are fixed biased, isn't it just that Mesa has them biased pretty cold and doesn't put in a pot to adjust the bias easily???.... this is not at all the case. although there are many out there that are fixed bias, there are many, many more that are not. most fender & marshall stuff is not fixed bias, and their copies (sovtek, old traynors, et al) follow suit.Mesa, Carvin, & Peavey are big fans of the 'fixed bias' designs, and generally are considered to be biased (stock) a bit cold. whether thats good or bad is up to the user. Link to comment Share on other sites More sharing options...
Members Stratotone Posted May 3, 2006 Members Share Posted May 3, 2006 Anything in your fx loop? might also want to try a guitar cable running from the send to receive if there's not anything. Amps with fx loops can have dirty/intermittent switching jacks for the fx loop and cause all sorts of grief like you're experiencing. Pete Link to comment Share on other sites More sharing options...
Members tigger_ferret Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by L6Sguy this is not at all the case. although there are many out there that are fixed bias, there are many, many more that are not. most fender & marshall stuff is not fixed bias, and their copies (sovtek, old traynors, et al) follow suit. Mesa, Carvin, & Peavey are big fans of the 'fixed bias' designs, and generally are considered to be biased (stock) a bit cold. whether thats good or bad is up to the user. Actually I'm pretty sure you will find that probably about 90% of Fenders and Marshalls are fixed biased unless you are talking about maybe a tweed deluxe or something from the 50's that is cathode biased.Fixed bias doesn't actually mean that you cannot rebias without completely changing the specific resitor.Have a look at http://www.aikenamps.com/ if you are actually interested in all the electronics tech info. Plus there are a million more helpful resources on this kinda stuff all across the netitstartsstoppin I hope we haven't confused you to much, the end pointYour probably fine just putting in a new set of tubes without checking the bias (this is how mesa designed there amps) but it is something that you can still get a GOOD tech to have a look at if you wish.On top of the checking tubes and to rebias/ not to rebias arguement, it may not even be your tubes that are causing the problem so it may still be a good idea to take it to a tech Link to comment Share on other sites More sharing options...
Members shepherdspy Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by hbar Take the cord out of the tact and see if the problem persists. That was funny but you should have spelled it "chord" like he did. Amp Faq for nontechnical dudes - Check the cables, check the fuses, check the tubes. Replace the cables with known goods, replace the fuses with proper type, replace ALL the power tubes and rectifier(s) with brand new ones, if necessary, then replace all the preamp tubes. If none of that works it is time to find an amp tech.Good luck, itstartsstoppin, Doug's Tubes will set you right. Link to comment Share on other sites More sharing options...
Members hbar Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by shepherdspy That was funny but you should have spelled it "chord" like he did. I didn't catch that until after I posted, and I thought it would have been lame to go back and edit it. Now I'm sorry I didn't. I was pretty proud of that post, if I do say so myself. And clearly I did. Link to comment Share on other sites More sharing options...
Members inscho Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by L6Sguy this is not at all the case. although there are many out there that are fixed bias, there are many, many more that are not. most fender & marshall stuff is not fixed bias, and their copies (sovtek, old traynors, et al) follow suit. Mesa, Carvin, & Peavey are big fans of the 'fixed bias' designs, and generally are considered to be biased (stock) a bit cold. whether thats good or bad is up to the user. fixed bias-you have to bias your ampcathode bias-you don't Link to comment Share on other sites More sharing options...
Members L6Sguy Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by inscho fixed bias-you have to bias your amp cathode bias-you don't oops tiger-ferret, my apologies. Link to comment Share on other sites More sharing options...
Members AmpliFIRE Posted May 3, 2006 Members Share Posted May 3, 2006 Originally posted by L6Sguy oops tiger-ferret, my apologies. +1DOH! Link to comment Share on other sites More sharing options...
Members PFLOYD Posted May 5, 2006 Members Share Posted May 5, 2006 HEY MAN, I'LL BET THAT IF YOU HAVE AN EFFECTS LOOP IN AND OUT ON THE BACK OF THE AMP, ONE OF THE JACKS MIGHT BE THE CAUSE OF THE CUT OUT. TO FIND OUT, TAKE A GUITAR CORD AND PLUG IT INTO THE OUTPUT JACK, THEN PLUG THE OTHER END INTO THE INPUT JACK. I HAVE A BOOGIE MARK III AND HAD THE SAME PROBLEM... I GOT A SHORT GUITAR CORD, PLUGGED IT IN AND FIXED THE PROBLEM... I LEAVE THE CORD IN THE JACKS. Link to comment Share on other sites More sharing options...
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