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FDP Forum / Amp Mods, Repairs, and Projects / Mission 57 Tweed crackling sound

zeedawg Contributing Member *** USA Praise him with the strings	Feb 2nd, 2012 08:25 PM   Edit   Profile   Print Topic   Search Topic Hi all. I've posted this before, been trying to chase this one day for about 8-9 months! When the Amp warms up after playing about 5 minutes, it give a crackling sound like someone wading up a piece of paper. I looked at all solder joints, one looked weak, so retouched it. I also was a little concerned with #1 tube socket, so replaced that. The sound only happends when I strike a cord or pick a note. It stops as soon as I mute the strings. Any help would be awesome. Thanks
cisco Contributing Member **** Tucson, Arizona USA Bottom Sucker	Feb 3rd, 2012 09:13 AM   Edit   Profile   Print Topic   Search Topic Could be a bad pre-amp tube. Have you switched them out yet?
zeedawg Contributing Member *** USA Praise him with the strings	Feb 3rd, 2012 06:49 PM   Edit   Profile   Print Topic   Search Topic Switched all the tubes one at a time, 2 new complete sets. Sounds like a tube, but nope.
cisco Contributing Member **** Tucson, Arizona USA Bottom Sucker	Feb 4th, 2012 11:12 AM   Edit   Profile   Print Topic   Search Topic Could be a cracked solder joint.
SoK66 Contributing Member **** USA We had the hit but Van got the money	Feb 4th, 2012 01:02 PM   Edit   Profile   Print Topic   Search Topic Ditto. I'd try flowing all of the solder joints. Sometimes these can't be easily seen. This seems to be a consistent issue with kit builds.
amphead4 Cincinnati, USA	Feb 4th, 2012 10:33 PM   Edit   Profile   Print Topic   Search Topic Also try a different speaker. I had a pair of Jensens in a Bassman cab that had bad tinsel wires.
zeedawg Contributing Member *** USA Praise him with the strings	Feb 18th, 2012 03:03 PM   Edit   Profile   Print Topic   Search Topic cisco/SoK66, been trying to chase that one down. Long process, but getting through it (lot of solder joints :-). Amphead4, never thought about the speaker. I had changed the speaker a couple months back to a 1960 Jensen P12Q to keep with the vintage vibe of this amp. It made an amazing difference. I can't recall if thats when the noise started, but it's easy enough to put the one back in that came with the kit. Worth a try! Thanks.
SoK66 Contributing Member **** USA We had the hit but Van got the money	Feb 18th, 2012 08:08 PM   Edit   Profile   Print Topic   Search Topic Try it through a different speaker and see if the racket goes away.
zeedawg Contributing Member *** USA Praise him with the strings	Feb 19th, 2012 12:16 PM   Edit   Profile   Print Topic   Search Topic Ok, put my original DRRI C12K in it, basically a brand new speaker, and so far (fingers crossed) it's been playing great. Granted it's only been a couple hours, but usually by now the noise would have already started. Kudos to you all if this is it. I've spent months trying to track this down, tubes, wiring, solder joints, and never once thought about the speaker. I was going for the "as much vintage as I would" approach with the '60 speaker and all JAN NOS tubes. But it actually sounds pretty good with the ceramic in there. I'll play hard for a few more days before I'm convinced and will report back. -Z
jchabalk Northern California	Feb 27th, 2012 11:42 PM   Edit   Profile   Print Topic   Search Topic check the input jacks! take the rear cover off and let the amp warm up to where it's making the noise you're talking about. Put the volumes/tone at the 5-6 mark then take a chopstick and gently push on each input jack individually - where the tip of the guitar cable would contact. I'm assuming that you have the shorting input jacks here - i built a mission kit and that's the type of jack i had. check each one and see if the sound you're talking about is reproduced I had what sounds like a very similar problem a while ago and it was driving me crazy. If that ends up being a problem there are 2 ways to address it: 1) cut a piece of business card (or any sort of heavy paper-stock) into a small enough piece that it'll fit between the tip of the jack and the part that shorts it out. drag it through there a bunch of times to pick up the grease/metal dust etc. 2) if that doesn't work replace the jack
jchabalk Northern California	Feb 27th, 2012 11:51 PM   Edit   Profile   Print Topic   Search Topic one other question, was your speaker wire soldered in place on the previous speaker or attached with speaker clips?
rfrakes331K Contributing Member USA RonHalen Jokingly He Says	Feb 28th, 2012 03:27 PM   Edit   Profile   Print Topic   Search Topic What about sockets tha need cleaned or retension? Dirty socket contacts can cause crackling and frying noises. Too bad it wasn't bacon frying!
zeedawg Contributing Member *** USA Praise him with the strings	Mar 1st, 2012 09:27 PM   Edit   Profile   Print Topic   Search Topic The speaker is soldered on. I did clean and retention the sockets, actually replaced one that just felt too loose. I've pulled the board out and re-soldered all the contacts. Driving me nut. Before the cracking starts, it's a great sounding amp and I want to play it so bad! I'll try the warm jack chopstick method.
zeedawg Contributing Member *** USA Praise him with the strings	Mar 17th, 2012 07:22 PM   Edit   Profile   Print Topic   Search Topic No luck! One thing I did try when it started to make the noise is tap on all the tubes, even though they've been replace Except the rectifier. When I tap that one it goes silent?? I'll try replacing and see if it's that simple
zeedawg Contributing Member *** USA Praise him with the strings	Mar 26th, 2012 09:55 PM   Edit   Profile   Print Topic   Search Topic Nope, not that either. Tubes all seem fine. Jacks seem fine. I've re-melted all the solder joints just in case a cold or cracked one. Nada. It must be one of the cap's I guess. Not sure how to check those, might be time to bring it in :-( I live close to Fritz, maybe I can get him to do his magic. Just frustrated, "I" want to fix it, ME, I built it ;-)
Mike62Jazz Contributing Member ****** USA/Colorado Mike	Mar 28th, 2012 07:32 AM   Edit   Profile   Print Topic   Search Topic Just curious! Have you contacted Bruce?
zeedawg Contributing Member *** USA Praise him with the strings	Apr 21st, 2012 04:24 PM   Edit   Profile   Print Topic   Search Topic Mike62Jazz. Yes I've contacted Mike. It was real hard for him to diagnose given the info I gave him. It's been about a month now that I've written, and now it's even worse. As soon as I power up the amp it starts making the sound, bad! At a loss. How do I check the caps, ohm meter? I'm determined!!! Thanks -Z
MarkJ61 USA	Apr 30th, 2012 05:43 AM   Edit   Profile   Print Topic   Search Topic I just noticed your thread, after searching for some speaker suggestion for my Clark Beaufort. Anyway FWIW, I had a similar issue with the same type of noise years back with a Fender that ended up being a bad power tube socket that was shorting across contacts. I could also see a small hairline crack in the phenolic. I think I discovered it by actually seeing a small arcing spark at the socket (leads side) when I had the chassis pulled. Maybe try doing the same in a dark-ish room. It's worth a shot. (This message was last edited by MarkJ61 at 09:04 AM, Apr 30th, 2012)
pdf64 UK	May 2nd, 2012 06:54 AM   Edit   Profile   Print Topic   Search Topic If the amp chassis is physically seperated from the speaker cab, does that help (eg a vibration induced bad connection)? If not, another possibility is parasitic oscillation. The 'crackles' may be blips of oscillation, though it's less likely than a bad contact / dry joint. It's not usually a problem with 5E3, as the gain is fairly low, but it's certainly possible. Post links to some build photos if possible. Consider wire runs, especially the OT wires to the output tube plates - keep them tucked well away from anything else, also the wire from the vol controls to V2 grid; maybe replace it with screened cable. Pete.

FDP Forum / Amp Mods, Repairs, and Projects / Mission 57 Tweed crackling sound

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