Members Chrisjd Posted March 17, 2008 Members Share Posted March 17, 2008 My friend has a amp with 4, 8, and 16 ohm selectores and 8 ohm cab, he had the amp set to 16 ohms going into the 8 ohm setting of the cab. he said the amp didnt sound quite right. I put it into the proper setting, 8 ohm selector from head into the 8ohm mono jack on the cab. would this have damaged his output transformer? the amp works fine but he is worried that he might have prematurely damaged it and is afraid it might break early on him or have problems. anything to worry about? Link to comment Share on other sites More sharing options...
Members knucklefux Posted March 17, 2008 Members Share Posted March 17, 2008 it's fine. Link to comment Share on other sites More sharing options...
Members Chrisjd Posted March 17, 2008 Author Members Share Posted March 17, 2008 it's fine. thanks.... Any other opinions??? Link to comment Share on other sites More sharing options...
Members guitarman967 Posted March 17, 2008 Members Share Posted March 17, 2008 My friend has a amp with 4, 8, and 16 ohm selectores and 8 ohm cab, he had the amp set to 16 ohms going into the 8 ohm setting of the cab. he said the amp didnt sound quite right. I put it into the proper setting, 8 ohm selector from head into the 8ohm mono jack on the cab. would this have damaged his output transformer? the amp works fine but he is worried that he might have prematurely damaged it and is afraid it might break early on him or have problems. anything to worry about? There's not too much in between with this stuff man, either it blew up or it's fine. Tube amps are not really as susceptible to damage by impedience mismatches as some will have you believe..As long as he doesnt make a habit of it, the amp will be fine Link to comment Share on other sites More sharing options...
Members lackingimpact Posted March 17, 2008 Members Share Posted March 17, 2008 it's a safe mismatch Link to comment Share on other sites More sharing options...
Members Chrisjd Posted March 17, 2008 Author Members Share Posted March 17, 2008 There's not too much in between with this stuff man, either it blew up or it's fine. Tube amps are not really as susceptible to damage by impedience mismatches as some will have you believe.. As long as he doesnt make a habit of it, the amp will be fine thank you wise one. Link to comment Share on other sites More sharing options...
Members Chrisjd Posted March 17, 2008 Author Members Share Posted March 17, 2008 it's a safe mismatch good. Link to comment Share on other sites More sharing options...
Members knucklefux Posted March 17, 2008 Members Share Posted March 17, 2008 it's a safe mismatch actually no, but it's still OK. amp on 8 ohms into a 16 ohm cab is OK. Link to comment Share on other sites More sharing options...
Members guitarman967 Posted March 17, 2008 Members Share Posted March 17, 2008 thank you wise one. Anytime my man:wave: Link to comment Share on other sites More sharing options...
Members guitarman967 Posted March 17, 2008 Members Share Posted March 17, 2008 it's a safe mismatch Do you run your amp 16 into 8? Link to comment Share on other sites More sharing options...
Members redeye5 Posted March 17, 2008 Members Share Posted March 17, 2008 bad Link to comment Share on other sites More sharing options...
Members Weathered Posted March 17, 2008 Members Share Posted March 17, 2008 actually no, but it's still OK. amp on 8 ohms into a 16 ohm cab is OK. Either way is usually OK as long as it's within one setting (16 into 8, 8 into 4, etc), but there is no hard/fast rule on what is and is not OK. It depends on the OT. Link to comment Share on other sites More sharing options...
Members Phade21 Posted March 17, 2008 Members Share Posted March 17, 2008 If the output transformer was destroyed there wouldn't be any sound coming out at all...and as said before...it's a safe mismatch. Link to comment Share on other sites More sharing options...
Members Chrisjd Posted March 17, 2008 Author Members Share Posted March 17, 2008 thanks dudes. Link to comment Share on other sites More sharing options...
Members Erock503 Posted March 17, 2008 Members Share Posted March 17, 2008 so are Mesa amps different from all other amps? Every Mesa manual lists using a higher impedance cab with a lower amp setting as a safe mismatch, while running a smaller impedance cab than the head setting is an unsafe mismatch. It explains that the OT pushes less current with a safe mismatch, and as a result, the tranny runs cooler which darkens the tone slightly. It works out mathematically too, power loss in either direction with a matching OT, but less current with a higher impedance cab. Why is the general consensus around here that running a lower impedance cab than the amp is set at is a "safe mismatch?" Are Mesa amp circuits just built different than everything else? Link to comment Share on other sites More sharing options...
Members Weathered Posted March 17, 2008 Members Share Posted March 17, 2008 Lower impedence cab = tubes work harder. Higher impedence cab = potentially no issues, but possiblity of "flyback" voltages on the OT. Link to comment Share on other sites More sharing options...
Members JerryP Posted March 17, 2008 Members Share Posted March 17, 2008 Run the amp and cab matched or you risk damage, period end. Nobody can predict if or when you will have a problem or how extensive the damage will be, but the likelyhood is very real if you choose to run it any other way than it was designed. Running one way or the other doesn't matter, both are bad. An output transformer can arc inside and still work. It doesn't have to have no output to be damaged. Flyback voltages will cause the B+ voltage to climb extremely high and many times will cause the OT to arc inside and cause power tubes to short between pins 2 & 3. Once the OT arcs inside it will usually work at low levels, but when pushed it will blow fuses and arc over tubes.Jerry Link to comment Share on other sites More sharing options...
Members Chrisjd Posted March 17, 2008 Author Members Share Posted March 17, 2008 Run the amp and cab matched or you risk damage, period end. Nobody can predict if or when you will have a problem or how extensive the damage will be, but the likelyhood is very real if you choose to run it any other way than it was designed. Running one way or the other doesn't matter, both are bad.An output transformer can arc inside and still work. It doesn't have to have no output to be damaged. Flyback voltages will cause the B+ voltage to climb extremely high and many times will cause the OT to arc inside and cause power tubes to short between pins 2 & 3. Once the OT arcs inside it will usually work at low levels, but when pushed it will blow fuses and arc over tubes.Jerry Will the amp sound different if the OT arcs? and way of telling whether or not this happened? Link to comment Share on other sites More sharing options...
Members Lucius Posted March 17, 2008 Members Share Posted March 17, 2008 Will the amp sound different if the OT arcs? and way of telling whether or not this happened? It will sound like this --------------------------------------------. Cheers, Lucius:lol: Link to comment Share on other sites More sharing options...
Members JerryP Posted March 17, 2008 Members Share Posted March 17, 2008 Will the amp sound different if the OT arcs? and way of telling whether or not this happened? If the amp isn't blowing fuses at high volumes or having low output and sounding like a fuzz box I would say you're OK.Jerry Link to comment Share on other sites More sharing options...
Members Erock503 Posted March 17, 2008 Members Share Posted March 17, 2008 Run the amp and cab matched or you risk damage, period end. Nobody can predict if or when you will have a problem or how extensive the damage will be, but the likelyhood is very real if you choose to run it any other way than it was designed. Running one way or the other doesn't matter, both are bad. An output transformer can arc inside and still work. It doesn't have to have no output to be damaged. Flyback voltages will cause the B+ voltage to climb extremely high and many times will cause the OT to arc inside and cause power tubes to short between pins 2 & 3. Once the OT arcs inside it will usually work at low levels, but when pushed it will blow fuses and arc over tubes. Jerry thanks Jerry, I've been wondering about this for a while too. Link to comment Share on other sites More sharing options...
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