Members cdp Posted June 11, 2006 Members Share Posted June 11, 2006 Ran an 8 ohm extension cabinet along with the Shiva (combo) 12" speaker. Split the signal coming out of the Shiva (normally 16 ohm) into two 8 ohm signals. Done it exactly this way dozens of times. The problem is... The speaker jack came out of the extension cabinet, so I played a 1 hour set with unbalanced load (forgive my lack of technical expertise) and the amp shut off 45 minutes into the set. The tubes glow, but no output at all. Any ideas what burned out and how much $$$$ this will cost? I'm putting her into the shop on Monday morning. Link to comment Share on other sites More sharing options...
Members guitarded_1 Posted June 11, 2006 Members Share Posted June 11, 2006 Let's hope it's not your OT. Link to comment Share on other sites More sharing options...
Members AnomalyXT Posted June 11, 2006 Members Share Posted June 11, 2006 I'm no tech, but I'd put my money on a blown output transformer. I don't know how much it'll cost you, but I'd expect maybe the $100-$200 ballpark? Link to comment Share on other sites More sharing options...
Members cdp Posted June 11, 2006 Author Members Share Posted June 11, 2006 ouch. Thanks for the replies, BTW. Link to comment Share on other sites More sharing options...
Members Ancient Mariner Posted June 11, 2006 Members Share Posted June 11, 2006 Yup, OT most likely. Link to comment Share on other sites More sharing options...
Members Zakko Posted June 11, 2006 Members Share Posted June 11, 2006 So you basicly ran a 16 ohm out into an 8 ohm setup? You could just have to replace all the power tubes however, signs point to OT. Link to comment Share on other sites More sharing options...
Members BadHorsie Posted June 11, 2006 Members Share Posted June 11, 2006 I'm no amp tech, but in the real world I repair hoisting equipment. I deal with transformers in that capacity and when they go, it's usually due to heat- an unbalanced load can certainly induce heat, as can a voltage problem. That being said, a blown trans will usually smell or appear burnt. The casing can warp, and the insulation around the winding can get scorched. If your trans is bad, it should be pretty obvious. Link to comment Share on other sites More sharing options...
Members cdp Posted June 11, 2006 Author Members Share Posted June 11, 2006 I sense an Output Transformer in my very near future, lol. The worst thing about it was having to finish the show going from my pedalboard into a direct box. The tone SUCKED. Oddly, I know a few (electric) guitarists who go the direct box route at every show. I don;t get it. Link to comment Share on other sites More sharing options...
Members sufidancer Posted June 11, 2006 Members Share Posted June 11, 2006 Before you do anything just try another speaker to see if you get any audio signal. Chances are your O.tran is gone but you may be lucky and just fried the voice coils in the speakers. Maybe..goodluck. Cant hurt to try. Link to comment Share on other sites More sharing options...
Members BadHorsie Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by cdp I sense an Output Transformer in my very near future, lol. The worst thing about it was having to finish the show going from my pedalboard into a direct box. The tone SUCKED. Oddly, I know a few (electric) guitarists who go the direct box route at every show. I don;t get it. Look at the bright side- now you have an excuse to get one of those Mercury Trans' like the one Voodoo just put in my amp. Think of your amp as Steve Austin. "Gentlemen, we can rebuild him.":thu: Link to comment Share on other sites More sharing options...
Members cdp Posted June 11, 2006 Author Members Share Posted June 11, 2006 Originally posted by BadHorsie Look at the bright side- now you have an excuse to get one of those Mercury Trans' like the one Voodoo just put in my amp. Think of your amp as Steve Austin. "Gentlemen, we can rebuild him.":thu: Mercury Trans???? I'm intrigued - do tell us more about it! keep in mind that I like my amps clean with just a hint of gain - and get my OD and Distortion from my stomp boxes... Link to comment Share on other sites More sharing options...
Members ProjectX Posted June 11, 2006 Members Share Posted June 11, 2006 Did you check both fuses?If the HT fuse blew you would still have the tubes lit up. Link to comment Share on other sites More sharing options...
Members Cibyl Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by ProjectX Did you check both fuses?If the HT fuse blew you would still have the tubes lit up. +1 That's what I was gonna suggest,...check that first before jumping to the "worst" conclusion. Link to comment Share on other sites More sharing options...
Members cap'n'crunch Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by cdp Ran an 8 ohm extension cabinet along with the Shiva (combo) 12" speaker. Split the signal coming out of the Shiva (normally 16 ohm) into two 8 ohm signals. Done it exactly this way dozens of times. Are you saying that the amp is set to 16 ohms and you are using 2 - 8 ohm loads? Link to comment Share on other sites More sharing options...
Members LoudMarshalls Posted June 11, 2006 Members Share Posted June 11, 2006 Check the fuse as was stated earlier. Its designed to protect your OT and more than likely its either that or tubes and not the OT. Link to comment Share on other sites More sharing options...
Members ProjectX Posted June 11, 2006 Members Share Posted June 11, 2006 He's saying he was running the internal 16 ohm combo speaker and an 8 ohm extension cab.That's a mismatch right there.What's not clear is what he had the impedance on the amp set at. Link to comment Share on other sites More sharing options...
Members NiCkMiLnE Posted June 11, 2006 Members Share Posted June 11, 2006 ^exactyl, blown OT Link to comment Share on other sites More sharing options...
Members PhilBelanger Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by ProjectX Did you check both fuses?If the HT fuse blew you would still have the tubes lit up. +2 Link to comment Share on other sites More sharing options...
Members JamesPeters Posted June 11, 2006 Members Share Posted June 11, 2006 I doubt it's a blown OT, although it's possible. It's more likely the output tubes failed (and, never just look at them and assume they're ok because they're "lit"). So try new output tubes, bias the amp, replace whatever fuses you need to, and see how that goes. Check for carbon on the sockets when you change the tubes too. You'll need to completely remove it from above and below the socket if any exists, and replacing the sockets is the best idea in this case. Good luck. Link to comment Share on other sites More sharing options...
Members JerryP Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by JamesPeters I doubt it's a blown OT, although it's possible. It's more likely the output tubes failed (and, never just look at them and assume they're ok because they're "lit"). So try new output tubes, bias the amp, replace whatever fuses you need to, and see how that goes. Check for carbon on the sockets when you change the tubes too. You'll need to completely remove it from above and below the socket if any exists, and replacing the sockets is the best idea in this case.Good luck. +1Jerry Link to comment Share on other sites More sharing options...
Members potaetoes Posted June 11, 2006 Members Share Posted June 11, 2006 you've been running the 16-ohm output into a 4-ohm total load "dozens of times"... that's bad. Link to comment Share on other sites More sharing options...
Members cap'n'crunch Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by potaetoes you've been running the 16-ohm output into a 4-ohm total load "dozens of times"...that's bad. +1 Thats what I thought he was saying.2 - 8 ohms in parallel = 4 ohms. Link to comment Share on other sites More sharing options...
Members potaetoes Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by cap'n'crunch +1 Thats what I thought he was saying.2 - 8 ohms in parallel = 4 ohms. it's mainly bad for power tubes though, which is probably what fried, possibly taking out some other parts with them. Link to comment Share on other sites More sharing options...
Members ProjectX Posted June 11, 2006 Members Share Posted June 11, 2006 Yup,if the screed grid resistors go,the HT will keep blowing. Link to comment Share on other sites More sharing options...
Members Variable Posted June 11, 2006 Members Share Posted June 11, 2006 Originally posted by cdp Ran an 8 ohm extension cabinet along with the Shiva (combo) 12" speaker. Split the signal coming out of the Shiva (normally 16 ohm) into two 8 ohm signals. Done it exactly this way dozens of times. The problem is... The speaker jack came out of the extension cabinet, so I played a 1 hour set with unbalanced load (forgive my lack of technical expertise) and the amp shut off 45 minutes into the set. The tubes glow, but no output at all. Any ideas what burned out and how much $$$$ this will cost? I'm putting her into the shop on Monday morning. I've blown the OT on a Rivera. You cannot miss the smell. It's like burning nasty Elmer's glue. That said, I agree with those who say you may have just blown a fuse or wrecked your power tubes. Link to comment Share on other sites More sharing options...
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